Simple upgraded stereo with OEM stealthiness

[ky650]

Hi All,

I was recently inspired by a post Turbo2go had started to finally redo my sound sysystem. Like him I wanted to keep a stock appearance and was intrigued by what he had to say about using smaller drivers that were a better fit for the OEM enclosures. I took his findings as a starting point and ordered a bunch of different 4" drivers and tweeters off parts express ranging in price and frequency response to get an idea of what the gamut was like. The goal was to stick to a single woofer in each door, oem enclosure, use the existing wiring and head unit, and replace the oem subwoofer with a compact class d amplifier that would run cool enough to be tucked away in an unventilated area. Cutting up my dash/doors for tweeters or having the amplifier visibile behind the driver seat just didn't really appeal to me.

I started out by removing the bose driver, cutting out the grille, and making a simple MDF spacer like turbo had done. Just to keep things fast and simple I hooked the speakers up to my home amplifier/dac setup so I wouldn't have to deal with the more awkward positioning, wiring, and what not. After a bit over an hour of listening I felt I had a clear winner.


From left to right

OEM Bose driver
eek this thing sounds bad

Dayton MD105-4 4" mid-bass driver
http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=290-212
I believe this is the same driver turbo2go was using, it has a lot of excursion and as a result puts out some solid bass for its size. The people I've shown it too really can't believe that this much bass is coming from a 4" driver, it sounds similar to my Dad's 6.5" Dynaudio setup in a Boxster bass-wise which is quite a feat IMO

Tang Band w4-105SDF 4" full range driver
http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=264-913
I was wondering if it'd be worth sacrificing the bottom end 10 hz (60-70hz) for an additional 7,000 hz extension on the high end to get away without a tweeter but unfortunately the mids and highs were just too harsh I immediately abandoned that idea

Tang Band w4-1720 4" mid-bass driver
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-872
This driver had the bass of the Dayton but with far more clarity and imaging, definitely the best of the bunch by a good margin IMO

The Tang Band 1720 was a far larger driver than the Bose (and it weighs a ton) so I needed a 1/2" spacer to even make it fit within the stock enclosure and give something for the front mounting frame to rest on. I ended up CADing up something and 3d printing it to save time and it worked out pretty well.




Next up I mounted it in the car


After a quick listen I was pretty bummed to find they sounded so different than they had in the house. The highs were gone along with the sound stage but that made sense considering the drivers were by my feet pointed in the wrong direction and I was now using a $150 amp with an iphone instead to drive them. I figured I'd have to pull out some of the tweeters and see what could be done and much to my dismay they solved everything, the soundstage was back front and center and so were the highs. The only place I could think to hide a (single) tweeter was in the center HVAC duct; the central location seemed optimal and only a cheap blowmolded duct had to be modified to make it happen (where nobody would ever see). Luckily it was a pretty decent location being centrally positioned and at about the right height and the vents themselves didn't hurt the sound appreciably.



Just another 3d printed mount with 2 screws on the bottom along with a wire exit hole and another screw on top - its incredibly secure and there's no potential for rattling. Airflow is obviously blocked a bit but it seemed fine considering, I'd probably have to do a back to back comparison to notice.


Here it is installed, and once the vent goes on over it you can't see anything at all thanks to the black unless you shine a flashlight in there

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=264-1002
This is the tweeter I ended up using, nice and compact and not too bright

Next up was the amplifier. I ended up making an aluminum bracket that mounted to the OEM subwoofer mounting locations that would allow me to then mount my Alpine amplifier (and it weighs less than the factory steel one score!). Everything is nice and secure, theres a bit of breathing room in front of the amp (in between the amp heatsinks and the factory aluminum footrest plate), and it *just* fits in snugly. The best part of it all was how easy it was to wire everything from the factory head unit and tap into the OEM speaker signal wires to power the new drivers.





Alpine MRP F300
http://www.alpine-usa.com/product/view/mrp-f300/
Here's the amplifier I'm using. There isn't really any room in the footwell for anything larger unfortunately but I can easily turn this up to volumes louder than I'd care to ever hear and without distortion. I measured them drawing ~9.3 watts with a bass heavy song on the multimeter which means there's ample headroom. According to my EE friend ~50W is about all the OEM signal wires can handle safely at the current length so I'd rather not push my luck (I've lit a pair of bose speakers on fire by over powering them before so I know it's definitely a possibility :biggrin.

I haven't gotten too much listening time in yet but so far I'm quite happy with the results considering how little I spent. Everything looks stock, weight gain is probably negligible considering I traded the subwoofer for the amp, the bass is low enough in the 60hz range that I don't feel like I'm missing a subwoofer (not that going down to 20hz wouldn't be nice), the sound is clean and non fatiguing and all for not much more than the price of repairing the factory bose amps.

Random Details:
-Amplifier power comes from the engine bay fuse box and is routed through the stock grommet the CD changer cable used to use, I preferred this method because I wasn't sure how to discreetly get the (blue arg) power cable across the engine bay where as it was quite easy to do this inside the cabin alongside the other cable harnesses
-SOS wiring harness used for getting the signal/remote and tapping back into the factory signal cables to the doors and repurposed for powering the drivers with the alpine amp
-amplifier grounding is done with one of the several available bolt mounts right above the amp/factory sub
-amplifier is configured in 4 channel mode with channels 1 and 2 driving the door woofers and channel 3 driving the single tweeter
-Grom audio bluetooth unit is the source (this thing is awesome!)

Anyways I just wanted to share since there was a lot of interest in Turbo's findings, this guy is definitely onto something :biggrin:

 

[Nefarious]

Very nice setup thus far! I bet having access to a 3D printer makes life so much easier now. I would love to get one for home as the prices continue to come down. Once you have the car finished and buttoned up, post some more pictures.

 

[blue_myriddn]

I bet having access to a 3D printer makes life so much easier now. I would love to get one for home as the prices continue to come down.

+1 3D printing is massive cool and has enormous impacts for auto customization - will be interested to see that flourish

 

[bngl3rt]

Still have your CAD files? I wonder if you'd be willing to share those or maybe have some of your bose-speaker-adapter brackets printed to sell.

 

[ky650]

Very nice setup thus far! I bet having access to a 3D printer makes life so much easier now. I would love to get one for home as the prices continue to come down. Once you have the car finished and buttoned up, post some more pictures.

Thanks! It definitely has its moments; I had originally milled MDF mounts but they didn't fit and so I fired up the printer around midnight and popped out the new design. Couldn't go to sleep knowing my NSX business was incomplete! 3d printing is awesome for testing ideas quickly and not having to worry about the realities of milling but it's rarely useful for the end product where a cosmetic finish is likely important. My printer is an FDM which prints ABS plastic (same material as the Bose enclosures if I'm not mistaken) but there's a textured finish from the printing tool path not the smooth surface you'd get from a milled or SLA part.

Everything's all back together in the interior and I'd take more shots but all you'd see is a stock interior with a few wrinkles in the center console trim paint :biggrin:

+1 3D printing is massive cool and has enormous impacts for auto customization - will be interested to see that flourish

Me too, it's great seeing so many Prime members cooking up stuff themselves!

Still have your CAD files? I wonder if you'd be willing to share those or maybe have some of your bose-speaker-adapter brackets printed to sell.

Of course, anything for the community :smile:
Here's a link to the file: https://dl.dropboxusercontent.com/u/5511614/Speaker Mount v2.STL



Random design notes:
-front face is basically as large as possible (upper portion is constricted by the enclosure port), the flanges at the bottom provide a mounting spot for drivers with 4 mounting screws
-back face of the mount has an odd shape to clear the triangular circle thing of the Bose enclosure
-I drilled through the wall of the Bose enclosure so that I could use the existing mounting bosses (reinforced part of the enclosure around the screws) that originally held the OEM driver, the mounting holes on this adapter line directly up with those bosses but allow you to screw the adapter on from the outside. You can use the same type of screw that held the driver in but you'll need a longer one (#8 sheet metal screw of ~1" if I remember correctly)
-driver mounting holes aren't in the CAD because I noticed that some drivers weren't truely concentric with the hole (offset slightly downward) and it was easier to simply drill the holes in by hand afterwards
-the Tang Band driver I went with was definitely the maximum size the enclosure/mount would allow (both in depth and bezel diameter) so if you're unsure if what you're thinking of fits be sure to check the orthographic drawing provided by Parts Express and make sure your choice is smaller
-the mount was designed knowing I'd be printing it out of ABS so it wasn't really optimized for other materials/fabrication processes, just a heads up

I wouldn't mind making some for others if there's interest but if that becomes a reality I'll need to do some digging to see what the Prime rules are for that first though.

Hope this helps some, feel free to let me know if you've got any other questions

 

[TURBO2GO]

This is very interesting, I think you've done a great job although I see a few issues. How did you cross over the single tweeter? I'm not quite sure how you are getting both stereo channels output from that tweeter. Are you using the amp's internal crossover and just one side? This is the biggest flaw in your design and where I think the most improvement can be made. Also, did you think about angling the drivers up and in like I did? The factory points them straight. This is an issue especially with these drivers.

 

[Valhalla]

ky650 - Very nice job. I wish you lived closer as I'd have you build this system for my car. For the price, it looks very good.

Dave - no offense. I followed your big stereo build too. But it seemed like a lot more work/money and effort. I'm just looking for something better than the stock Bose setup without emptying my pockets completely.

 

[TURBO2GO]

Why would I take offended man? We are all here to help each other. KY650 has done a great job, I'm just saying it can be improved. You can run 2 tweeters in stereo in the doors with a passive xover and get a lot better sound than one tweeter in the vent. That's acoustically just not very good for a number of reasons. One it's mono, two it's far from the woofer, three in center you lose imaging.

Ky650 I will pm you later today, maybe we can both work on a few things and you can help me make some plates.

 

[Caroline-NSX]

Clean and simple that's for sure! I like how you mounted tweeter in the AC vent but would that block the air in the left side vent? Anyways, looking good Ky650 :wink:

 

[ky650]

This is very interesting, I think you've done a great job although I see a few issues. How did you cross over the single tweeter? I'm not quite sure how you are getting both stereo channels output from that tweeter. Are you using the amp's internal crossover and just one side? This is the biggest flaw in your design and where I think the most improvement can be made. Also, did you think about angling the drivers up and in like I did? The factory points them straight. This is an issue especially with these drivers.

I'm afraid you're right on all counts. The tweeter isn't really crossed over per se, it's fed the entire channel's frequency response range which is obviously less than ideal (the amp has a high pass filter but it doesn't have the proper range to cut off at the right point) and yes, it's only receiving one channel rather than the ideal combined L+R. I agree that there would be an improvement on paper if this were done the right way but there's just so much ambient noise in the cabin I don't believe I'd realistically be able to tell the difference. I'm pretty into home stereo setups and initially was really excited to what I thought might be possible in the car but once the engine/road noise entered the picture (this is actually my first time with a working stereo in the NSX) I felt that the point of diminishing returns hit hard and fast for me; imaging, sound stage size, and all of the usual stuff simply took a back seat to just having non fatiguing, clean sound with some noticeable bass and highs. I'm all for doing things the right way, I just didn't see a way of accomplishing that here without a more complex and expensive system. For ~$250 I believe this was in the ballpark of repairing the OEM bose setup price wise but with the clean sound of a custom system, the catch being IMO it doesn't go the extra mile with a tuning for that last 25% if that makes any sense. I suppose you could say I was aiming for the the value of the spec miata as opposed to the 911 of sound systems here :redface:

Regarding the driver tilt that's a good point, I didn't test how much a difference the angle would make but you're right that would be a good freebee. The drivers I chose wouldn't really allow for much if any angle from what I recall but most others should.

ky650 - Very nice job. I wish you lived closer as I'd have you build this system for my car. For the price, it looks very good.

Dave - no offense. I followed your big stereo build too. But it seemed like a lot more work/money and effort. I'm just looking for something better than the stock Bose setup without emptying my pockets completely.

Thanks! This is my first time installing a car stereo and I'd say the hardest part was the awkward contorted positioning needed to unbolt things from the passenger footwell and digging up the wiring info needed from Prime; Mounting the tweeter and woofers within the car was the easy part. If you've got the time I'd definitely be more than glad to help walk you through it.

Why would I take offended man? We are all here to help each other. KY650 has done a great job, I'm just saying it can be improved. You can run 2 tweeters in stereo in the doors with a passive xover and get a lot better sound than one tweeter in the vent. That's acoustically just not very good for a number of reasons. One it's mono, two it's far from the woofer, three in center you lose imaging.

Ky650 I will pm you later today, maybe we can both work on a few things and you can help me make some plates.

Cool, it'd be great hearing your feedback. I know we have different takes on what level we're after for our respective systems but I'm sure your knowledge could easily help push things further. I had originally considered a crossover and two tweeters but wasn't able to find one I could buy off the shelf except for larger home speaker variants that wouldn't fit within the Bose enclosure (the rest of the door had space but more mounting would have to be created and the factory wiring further adapted). Wouldn't putting the tweeter with the woofer be rather far downwards to get much out of it?

Clean and simple that's for sure! I like how you mounted tweeter in the AC vent but would that block the air in the left side vent? Anyways, looking good Ky650 :wink:

The picture might be a bit misleading but the tweeter blocks about half of the drivers side of the vent. At lower fan speed settings the blockage isn't really noticeable but at max it's about half of the passenger's air flow. I always have both vents pointed at me anyways so I guess that mitigates the issue slightly. I think you've just issued a challenge, I may need to redesign the mount with thinner walls and an aggressive pointed cap in the back to lower the tweeter's drag coefficient :biggrin:

 

[dablackgoku1234]

Would there be any improvement in sound quality if one were to just replace the OEM Bose Driver to something like a Dayton Audio ND105-4 and keep everything else the same?

Edit: Also wondering if there is anything that can be done to the center speaker between the seats...I don't think I've actually heard anything from there...

 

[ky650]

Perhaps someone like Turbo can better comment on this since I haven't even heard the stock system in working order before but I'm inclined to say yes. I compared the Bose driver to the others with my home amplifier and thought it sounded terrible; I'd assume this would all translate to the car with the Bose amp as well. Perhaps my Bose drivers sounded especially bad because they were aged coming from a 91 (cosmetically they were fine and the rubber surround was undamaged and flexible though). I haven't been able to find the stats on the Bose amplifier but believe I saw somewhere at the driver was 1 ohm which is far lower than most drivers which if I'm not mistaken means the amplifier could be putting out a good deal less power with a 4 ohm driver like the Dayton. A quick test did show it was able to power the Tang Band driver fine at high volumes so the idea seems feasible (this was my original intent except I wasn't able to repair my amplifiers).

You could I suppose, there's certainly room back there. I didn't in fear it'd just mess with the soundstage, when I held a tweeter in that position with my hand while listening it just sounded odd having sound coming from that direction so I didn't pursue it.

- - - Updated - - -

Removal of the OEM mobile phone and cd changer, the 10 miles of cabling, and some unused Bose bits. :biggrin:

 

[TURBO2GO]

Would there be any improvement in sound quality if one were to just replace the OEM Bose Driver to something like a Dayton Audio ND105-4 and keep everything else the same?

Edit: Also wondering if there is anything that can be done to the center speaker between the seats...I don't think I've actually heard anything from there...

The center just provides ambience, you're not going to hear much out of it. The short answer to your question is no. The Bose amps are heavily equalized to match the characteristics of the Bose driver in that enclosure. Sticking that random equalization on a driver that is vastly different in response is going to have bad affects. Yes, it is 1 ohm, and showing the Bose amp a 4 ohm load also severely cuts down dynamic range and overall volume.

- - - Updated - - -

Anything under 6" starts to get extremely directional. 4" drivers certainly are. As I pointed out in my thread the factory speakers are at a poor angle. I had corrected thus with my baffle. If you're going to make one, may as well make it at the right angle.

 

[Valhalla]

You guys keep going. I like the OEM look and the low price tag. Perhaps there are even smaller tweeters that would do the job that could be placed in the vent area so that you could have two facing the occupants and still have some air blowing around.

A question for you both is, with ky650's brackets and drivers, could they be angled like Dave's and still fit?

 

[TURBO2GO]

No, the driver he has picked cannot be angled.

I am all for inexpensive and OEM... but there has to be some reasonable logic. This system he has, and again.... I admire and appreciate his work... May be better in some aspects but is actually much worse in other aspects than the OEM system. He has picked up slightly better frequency response but essentially created a semi-mono system. Drivers, enclosures, cabin volume, and equalization work in harmony together. If you just try to replace one part of the chain with something random, you are going to get something really weird. I certainly am not interested in creating something that at least in some ways is significantly worse than the OEM system. Not much point in that. Tweeters don't belong in the center vent... Unless you are ok with "mono". It's unnecessary anyway.... There is plenty of space behind the door panel for tweeters next to the woofer. The problem is the wire. I am looking into some solutions for that.

KY, if I send you my MDF mould can you make more of it from ABS? Or can we create one? I have absolutely maximized the possible angle. The bottom of my baffle is literally touching the door panel. It took a lot of trial and error.

I wouldn't waste any more time working on a tweeter solution in the center vent. Even a generic 4 ohm crossover at around 3Khz with a pair of cheap tweeters next to them will produce vastly superior results. If you want, I can send you some Xovers and tweeters to try in the door.

- - - Updated - - -

KY, is your car manual steering? Where is the EPS?

 

[ky650]

You guys keep going. I like the OEM look and the low price tag. Perhaps there are even smaller tweeters that would do the job that could be placed in the vent area so that you could have two facing the occupants and still have some air blowing around.

A question for you both is, with ky650's brackets and drivers, could they be angled like Dave's and still fit?

The tweeters I chose are already 3/4" and basically the smallest I found on parts express. I'm sure you could find something smaller but it'd probably be only a few millimeters, so not enough to make a difference. Perhaps the best way to go about it would be to reprint the entire duct so you could redesign it in a way where those divider walls in the center of it are holding the tweeter as well. This way you'd minimize space taken up by the tweeter by regaining that ~8mm per divider.

No, the driver he has picked cannot be angled.

I am all for inexpensive and OEM... but there has to be some reasonable logic. This system he has, and again.... I admire and appreciate his work... May be better in some aspects but is actually much worse in other aspects than the OEM system. He has picked up slightly better frequency response but essentially created a semi-mono system. Drivers, enclosures, cabin volume, and equalization work in harmony together. If you just try to replace one part of the chain with something random, you are going to get something really weird. I certainly am not interested in creating something that at least in some ways is significantly worse than the OEM system. Not much point in that. Tweeters don't belong in the center vent... Unless you are ok with "mono". It's unnecessary anyway.... There is plenty of space behind the door panel for tweeters next to the woofer. The problem is the wire. I am looking into some solutions for that.

KY, if I send you my MDF mould can you make more of it from ABS? Or can we create one? I have absolutely maximized the possible angle. The bottom of my baffle is literally touching the door panel. It took a lot of trial and error.

I wouldn't waste any more time working on a tweeter solution in the center vent. Even a generic 4 ohm crossover at around 3Khz with a pair of cheap tweeters next to them will produce vastly superior results. If you want, I can send you some Xovers and tweeters to try in the door.

- - - Updated - - -

KY, is your car manual steering? Where is the EPS?

Just for the record Turbo I really appreciate the criticisms and take no offense. You're spot on about the compromises I've opted to make based on my criteria, the question is can things be pushed further and still be within the envelope of constraints I've set. :smile:

I could be *really* off base here which is why I'm curious to try some of your suggestions but some of what you said sounds more theoretical than practical in regards to the NSX (and my constraints). I completely understand what you're saying and where you're coming from in relation to the home audio world where you have a low noise floor, high quality sources, and 100% of your mental energy to dissect every nuance during a listening session but my divergence from the audio ideals so far have come from the mind set of what's "good enough" to appreciate in a more practical sense when driving the NSX. With that said that doesn't mean I want to sloppily put together a system, say that's good enough, and call it a day, but if it comes down to parts becoming visible, costs shooting up, and all of that I'd definitely draw the line. So I wonder...
- Does angling the driver a few degrees get them back on axis enough to make up for the fact that a lower quality driver would have to be used in order to do it (this is the case with the 3 drivers I had chosen but perhaps you know of one that's compact enough to allow this without making SQ compromises)?
- Placing the tweeter next to other drivers is definitely ideal normally, but when that position is down low by your legs and being potentially blocked is it not preferable to separate the tweeter to another location instead so it's on axis?
- Having a mono channel tweeter setup degrades stereo imaging but with the vocalist often in the center anyways and your attention focused on the road, is it not better to have the frequency response fully represented (as opposed to no highs)? Personally I noticed during a quick drive that without a tweeter (~3000-20000hz) that my system sounded terrible where as I likely wouldn't spot out that the lead vocalist is slightly to the left with a guitar coming from the distant right while driving. For a car my audio preferences seem to be something like no sibilance (especially because I need higher volumes to overcome the engine)>relatively well represented frequency response (60-20k seems decent)>sound stage>imaging

I was definitely stumped on the wiring for the tweeter. My friend told me that the stock signal cable wiring was already at its limits power handling wise at its current length so I was hesitant to add another pair of drivers and put further power demands on them. This site is the reference used: http://www.powerstream.com/Wire_Size.htm with the assumption that the signal wires were 18 gauge and to get the current = square root (50WPC / 4 ohms) or 3.125. The max current is supposed to be 2.3 for 18 gauge and I can potentially push 3.125 (if I'm using the full 50WPC) which would really need 16 gauge to handle safely. Like I said before though when I measured things I was only drawing 9.3 watts so there's still headroom to spare. The original thought had been to try the tweeters down there as well with a crossover (which I wasn't able to find) and run the amplifier in bridged mode. As for the wiring solution you're looking into, do you mean tapping into the stock power cables that also run into the doors that were originally supplying the bose amplifiers?

Sure, I should be able to do that, just pass along any dimensions if you've got them already as well (if not I'll just do my best to replicate from measurements). I'm definitely willing to do a one off set for you and once I'm more familiar with your design we can perhaps optimize it for producing multiples; I just want to make sure I'm familiar with the part first before making a commitment I can't keep.

Okay okay, you're so adamant that this solution is better I'd be stupid not to take you up on this offer. It looks like it's time for a showdown! :biggrin:
I'd really appreciate it though, I think if we work at it we may find some great solutions. Let me know what you've found out with tweeter positioning in relation to the woofer as well. Depending on what you're thinking we could create a single mount that holds both the woofer and tweeter in place for a really simple install.

My car is a 91 without power steering. I'll send you a PM.

 

[Stephen@NCAutoUSA]

I like this idea. But why go through the trial and error when there's proven affordable solutions already put together that work? From everything with keeping things stock looking to keeping the cabin space and tweeter placement. It seems that you people are trying to reinvent the wheel.

 

[TURBO2GO]

Just for the record Turbo I really appreciate the criticisms and take no offense.

Thanks for being understanding and not taking things personally. That's how progress is made. I too appreciate your hard work on this.

Does angling the driver a few degrees get them back on axis enough to make up for the fact that a lower quality driver would have to be used in order to do it (this is the case with the 3 drivers I had chosen but perhaps you know of one that's compact enough to allow this without making SQ compromises)?

The driver you want in there is the one that produces the best response in the lower bass region, not overall sound through the spectrum. While you tested the 3 drivers and the TB sounded best to you, as you said yourself it wasn't the one with the best bass response. I have taken actual measurements, and although the driver I used was an Aura, it is the same as the Dayton which rebrands it. You were using them without a tweeter... and if we just add a tweeter and crossover, then I wouldn't call the Tang Band the better driver. It is also much less capable in terms of overall output... necessary in an NSX cabin especially with the targa off.

And yes, angling it make a HUGE difference in sound. You even saw this yourself as the speaker went low, and off axis, you lost most of the response you had in the room.

Placing the tweeter next to other drivers is definitely ideal normally, but when that position is down low by your legs and being potentially blocked is it not preferable to separate the tweeter to another location instead so it's on axis?

What is more important is stereo separation and equalizing path lengths. When you move the tweeters in, essentially for the driver the left tweeter where a majority of the image comes from, is now closer to the right ear. The opposite wrong thing holds true for the passenger. The right tweeter is now to their LEFT! This isn't "nuance", this is like a MAJOR flaw. Second thing is path lengths. While it is down low, you've increased the distance from yourself, and made the left and right tweeters more equidistant. That very much is like your ears moving to the center of the car, and makes the sound much more pleasing. Third benefit of course is that when the drivers are close, you don't wind up with all sorts of what is called "phase distortion", which I won't get into technically. So while you slightly lose on one count, you gain on three. You can also angle the tweeters up and into the center of the car. So although you are closer as the driver to the left speaker, its energy and angle is slightly away from you and more towards the passenger. Same with them. In short, I think you are worrying about a non-issue so long as the tweeter is mounted in a way that has a clear shot into the cabin. Here is a photo of the speaker system I first installed now owned by Nero Tenebre. With the door grille off, you can see how much room is actually there. I don't think too many have seen this.





So as you can see, the tweeter is to the side of the 6.5" woofer. It is angled up. I then moved it further up and to the side of the woofer so it had a very clear shot into the cabin, and angled in perfectly.

- Having a mono channel tweeter setup degrades stereo imaging but with the vocalist often in the center anyways

LOL... I'm laughing because Mr. "I want it simple and cheap and I don't hear nuances" is suddenly selling me on the fact that the vocalist is center.

You have a mono tweeter in the center of the car. That is not a center channel and your left and rights are missing their highs. It's just so wrong...

is it not better to have the frequency response fully represented (as opposed to no highs)?

Who said "don't have highs"? This is a compromise we just don't need to make.

As for the wiring solution you're looking into, do you mean tapping into the stock power cables that also run into the doors that were originally supplying the bose amplifiers?

No I am looking at an easy solution to get new wiring into the door. The problem with what you are trying to do is that you are buying random parts, woofers and tweeters, some of which are 4 ohm drivers but designed for home use, and trying to match them up together. What you have now for example, is quite random. If your woofer or tweeter is more sensitive by just 3db, it is going to play too way too loud or way too quiet compared to the other driver. Having separate amplifiers on the tweeters and woofers allows you to adjust for that sensitivity. You can do it passively as well if you are really good at designing crossovers. Which is part science and part art. This is why I elected to use the factory wiring on the woofers, and keep the tweeters out of the doors and on the dash (which is the spot with best angle, and with the most equidistant pathlengths).... but judging by the criticism I received because the tweeters were visible, I am going to look at moving them back to the door location with a properly designed passive crossover. Plug and play which is how most seem to like it. For myself, I will go active and keep the high end tweeters on my dash. You can barely see them. No one notices until I point them out.

Sure, I should be able to do that, just pass along any dimensions if you've got them already as well (if not I'll just do my best to replicate from measurements). I'm definitely willing to do a one off set for you and once I'm more familiar with your design we can perhaps optimize it for producing multiples; I just want to make sure I'm familiar with the part first before making a commitment I can't keep.

Great. PM me your address and I will mail it to you. It was done by hand. I didn't produce off of measurements. Can you get it back to me though? I only have my two prototypes.

- - - Updated - - -

I like this idea. But why go through the trial and error when there's proven affordable solutions already put together that work? From everything with keeping things stock looking to keeping the cabin space and tweeter placement. It seems that you people are trying to reinvent the wheel.

The current solutions are not so great to me. They are heavy, are not very OEM, and have compromises in sound quality because of faults in design, not because of limitations of cost. We are improving in every area.

 

[Stephen@NCAutoUSA]

Yeah but really how much weight compared to the tradition setup vs this other set up is the real question. And another would be what's considered not oem? I've and plenty others have run a stock head unit with aftermarket components/sub and amp. Would not oem be things that are seen and unseen or just things that are seen.

I haven't followed every page of the threads but of I were to keep things pretty much oem with weight in mind I'd have done this

1. Oem headunit or a stereo delete plate to save weight.
2. Some lightweight sub box which would probably need to be custom. You could probably make one out of carbon fiber weighting less than 2 pounds.
3. Slim sub.
4. Lightweight speaker baffles
5. Components
6. Sub
7. Amp.
8. Line output driver

I'll have to reread the thread and your posts when I revisit my setup later in the year. But that's probably what I'll be doing when I have time. The main components though are really both the same for all setups. Heavy source, heavy amp, heavy components.

 

[ky650]

I like this idea. But why go through the trial and error when there's proven affordable solutions already put together that work? From everything with keeping things stock looking to keeping the cabin space and tweeter placement. It seems that you people are trying to reinvent the wheel.

I can't say I'm terribly familiar with every solution out there, but I wasn't that excited about what I did happen to see for various reasons:

First would be amp placement, I believe most people either put them in the trunk or behind the seats. The trunk means running a lot of wires back and forth through the engine bay which I just didn't want to deal with in an installation sense and if you're hardcore about performance you could argue it has less preferable weight balance and higher CG haha. Behind the seats meant it'd be visible and someone could run the back of the seat into the amplifiers sharp heatsinks which I definitely wasn't a fan of. Turbo convinced me to try out these drivers which in turn showed me I was fine with this level of bass and therefore no longer needed the factory sub. The footwell location was great in the sense that it was completely hidden and very easy to wire to.

As for the drivers, the installs I have seen tend to center around a 6.5" woofer which means an entirely new mounting plate and enclosure or a lot of dynamat and this inevitably means more money and time for the install. The only reason to go with a 6.5" is to get better bass and going back to Turbo's findings, a 4" can actually do quite well. Obviously "quite well" is just my personal take on it but the bass response compares well to the one far more expensive 6.5" setup I've heard so I'm content. I suppose I'm thinking of it as doing more with less, kinda like the v6 in a certain lightweight sports car we love :smile:

Perhaps there's a bit of reinventing going on but hopefully some refinement comes out in the end, if not I'll be happy that I managed to replace the entire sound system for less than having the OEM bose amps repaired.

Regarding OEM, changing anything to an aftermarket part is deviating from OEM but the part that people only seem to care about is keeping an OEM look and possibly keeping things fully reversible.

 

[Hrant]

^ I like your philosophy of how you are going about this and prioritizing with common sense - especially regarding the engine noise and road noise for those who have deviated from totally stock configuration.

I am not a techie but I do agree with Dave regarding the tweeter - as far as the visual is concerned. If that can be incorporated in the door with the speaker/woofer then it would be an ideal for many.

 

[ky650]

Thanks for being understanding and not taking things personally. That's how progress is made. I too appreciate your hard work on this.

Completely agree, good discussion gives further opportunity to understand the project and refine it.

The driver you want in there is the one that produces the best response in the lower bass region, not overall sound through the spectrum. While you tested the 3 drivers and the TB sounded best to you, as you said yourself it wasn't the one with the best bass response. I have taken actual measurements, and although the driver I used was an Aura, it is the same as the Dayton which rebrands it. You were using them without a tweeter... and if we just add a tweeter and crossover, then I wouldn't call the Tang Band the better driver. It is also much less capable in terms of overall output... necessary in an NSX cabin especially with the targa off.

And yes, angling it make a HUGE difference in sound. You even saw this yourself as the speaker went low, and off axis, you lost most of the response you had in the room.

You're right, I was originally hoping one driver could take care of the entire frequency range negating the need for a tweeter and while happy with the on axis response in my home, off axis in the car completely killed the already borderline highs the driver produced (the lows were a lot stronger thanks to the NSX's small cabin). Since I then added a tweeter in after to make up for that I should only be considering the mid/bass performance of the driver but I did feel the Tang Band 1720 was better in that department as well. What I haven't heard is how it stacks up against the Aura/Dayton with that driver angled in the right direction, which you're suggesting is a worthwhile tradeoff that I'll be trying. Regarding output I may be missing something but both the Dayton/Aura and the TB 1720 have the same power handling with the TB actually having higher sensitivity, wouldn't that make it better (at least on paper)?

What is more important is stereo separation and equalizing path lengths. When you move the tweeters in, essentially for the driver the left tweeter where a majority of the image comes from, is now closer to the right ear. The opposite wrong thing holds true for the passenger. The right tweeter is now to their LEFT! This isn't "nuance", this is like a MAJOR flaw. Second thing is path lengths. While it is down low, you've increased the distance from yourself, and made the left and right tweeters more equidistant. That very much is like your ears moving to the center of the car, and makes the sound much more pleasing. Third benefit of course is that when the drivers are close, you don't wind up with all sorts of what is called "phase distortion", which I won't get into technically. So while you slightly lose on one count, you gain on three. You can also angle the tweeters up and into the center of the car. So although you are closer as the driver to the left speaker, its energy and angle is slightly away from you and more towards the passenger. Same with them. In short, I think you are worrying about a non-issue so long as the tweeter is mounted in a way that has a clear shot into the cabin. Here is a photo of the speaker system I first installed now owned by Nero Tenebre. With the door grille off, you can see how much room is actually there. I don't think too many have seen this.

So as you can see, the tweeter is to the side of the 6.5" woofer. It is angled up. I then moved it further up and to the side of the woofer so it had a very clear shot into the cabin, and angled in perfectly.

I'm imagining right now awkwardly holding out a tape measure from my ear to each driver in the car so I can say to you they are equidistant :tongue:
I hear you on the theory and look forward to hearing the difference in sound. Like all things sound related it's hard to understand these nuances when explained versus when heard. I will say that the biggest issue with SQ I have with the current setup is that the highs are detached within the sound stage, they're clearly front and center where they should be where as the mids/bass are more ambiguous. Sounds like your feedback could be the key to fixing this.

LOL... I'm laughing because Mr. "I want it simple and cheap and I don't hear nuances" is suddenly selling me on the fact that the vocalist is center.

You have a mono tweeter in the center of the car. That is not a center channel and your left and rights are missing their highs. It's just so wrong...

Are you really going to talk Mr. I want to save weight on a seat bracket but am putting a massive amplifier in the car? No wonder you needed that CTSC... Bose put in a center channel and they clearly know what they're doing, I just moved it to the front where it belongs :biggrin:

Technically the Left isn't missing it's highs... just saying haha

Who said "don't have highs"? This is a compromise we just don't need to make.

That was in reference to having the current setup or removing the tweeters and not having any highs, you're solution might obviously be the silver bullet here.

No I am looking at an easy solution to get new wiring into the door. The problem with what you are trying to do is that you are buying random parts, woofers and tweeters, some of which are 4 ohm drivers but designed for home use, and trying to match them up together. What you have now for example, is quite random. If your woofer or tweeter is more sensitive by just 3db, it is going to play too way too loud or way too quiet compared to the other driver. Having separate amplifiers on the tweeters and woofers allows you to adjust for that sensitivity. You can do it passively as well if you are really good at designing crossovers. Which is part science and part art. This is why I elected to use the factory wiring on the woofers, and keep the tweeters out of the doors and on the dash (which is the spot with best angle, and with the most equidistant pathlengths).... but judging by the criticism I received because the tweeters were visible, I am going to look at moving them back to the door location with a properly designed passive crossover. Plug and play which is how most seem to like it. For myself, I will go active and keep the high end tweeters on my dash. You can barely see them. No one notices until I point them out.

It's definitely random but looking at many home DIY speaker builds that isn't necessarily a bad thing, it's all about implementation (not saying I've necessarily hit the mark there). The tweeter is on a separate channel so I was able to adjust it's volume until it felt balanced to my ears, what I unfortunately wasn't able to do was cut out the lower frequencies passed to it for less distortion in the range I do care about. Unless I can get a new set of wires into the door a crossover for this round is going to be a must.

Great. PM me your address and I will mail it to you. It was done by hand. I didn't produce off of measurements. Can you get it back to me though? I only have my two prototypes.

Sure thing, now if you send some of those other mods on your car for me to try out I won't be able to make the same promise...

 

[racer-ex]

Updates...

 

[TURBO2GO]

Ky sensitivity measured at 1W/1M and peak power handling ratings will not always correlate to amplitude. Your assumption in this case that the TB will have greater output is not true.

You need to install a passive filter on that tweeter or you will damage it.

I forgot to send you my prototype baffles. How fast can you get them back to me? Seems like others are waiting to see what happens with all of this.

 

[ky650]

Updates... Turbo is too busy playing with his track goodies and I got side tracked with suspension :smile:

Do you happen to know of any good starter reading I could learn more about this stuff? Could you elaborate on the passive filter? When it comes to crossovers and any of that other stuff (or speaker building in general) I'm completely clueless. I can build enclosures, solder electronics, but completely lack any knowledge of what to do when it comes to this department.

I'd need a week minimum to do things, 2 would be nice but I can work around your schedule. I just sent back my Dayton drivers along with all of the other extra stuff. Would it be possible for you to send over your Auras as well so I can really work on getting things fit nicely? Have you chosen a specific tweeter and figured out the crossover as well? I'd love to make one nice bracket that holds everything together as cleanly as possible.