In search for a better sound quality

General conversations about BMW E28s and the people who own them.
sixseries
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Re: In search for a better sound quality

Post by sixseries »

Agreed. If you're not doing a sub, there's probably not really a need for an true amplifier.
DariusPri
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Re: In search for a better sound quality

Post by DariusPri »

Funny thing is while doing all the harnesses I was left with solid white and red wires. Maybe someone knows what are they used for?
The Truth
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Re: In search for a better sound quality

Post by The Truth »

Hey all, I just started nosing around to see if anyone offers any under seat subs for e28, as I make them for the 2002. We just got our first e28 and I was eyeballing the back seat yesterday at a stop light and just thought to look around today.
I have gone so far as to pre build full harnesses for customers and they have flown me to their home to install the systems..
I may cast the cavity under the seat this summer and make a plug for laying up glass enclosures, but I need to see the space to gauge if its got enough volume... We just use a 6.5" or 8" for the 2002 as it is really just a mid-bass to fill in the thin audio of a two or four speaker system, amp under the one side enclosure on the other. You can run speaker wire to the high input of the amp, or use a modern deck with RCA outs.. it works very nicely in the 2002.

www.boltonbliss.com/products
Philo
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Re: In search for a better sound quality

Post by Philo »

this begs a question. If you're running external power amps should the head's internal amp be shut off ?
topher800
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Re: In search for a better sound quality

Post by topher800 »

The Truth wrote: Jan 13, 2021 1:08 PM I have gone so far as to pre build full harnesses for customers and they have flown me to their home to install the systems..
I may cast the cavity under the seat this summer and make a plug for laying up glass enclosures, but I need to see the space to gauge if its got enough volume...
There are several threads that include subwoofers under the rear seat, you can see a picture of the one I had made here (scroll about 2/3 - 3/4 of the way down):

viewtopic.php?f=2&t=69254&start=5000
SlickDizzy
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Re: In search for a better sound quality

Post by SlickDizzy »

In regards to the main topic of this thread, I'm running a Kenwood head unit with Polk 4x6s up front and 6.5s in the rear shelf, with an NVX QBUS8v2 powered compact sub under the rear seat. No pillar tweeters, though I've considered adding them for better front imaging. I'm generally quite happy with the sound.

One interesting observation I made is that the OEM front 4x6 grilles are absolutely horrid for sound quality. I replaced them with an aftermarket set of mesh grilles and the sound quality/imaging from the front 4x6s increased by an order of magnitude. So that may be something to look at if you feel that your stereo has good components but still kind of sucks.
Philo wrote: Jan 13, 2021 1:13 PM this begs a question. If you're running external power amps should the head's internal amp be shut off ?
There is not really any way to do so on typical head units, but it wouldn't be necessary anyway. If there are no speakers connected to the internal amp, it doesn't have any significant load, so it's essentially an inert signal.

RCA connections on head units bypass the internal amp by design and utilize only preamp voltage so that's not a concern either.
cyclist
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Re: In search for a better sound quality

Post by cyclist »

I have one of the truth/boltonbliss under seat 02 sub boxes for the 6" jl series subs and he did a great job on the box. Would be great if he starts making them for the e28. I am in the mist of building a system for my e28. I am using a alpine cda-9887 for a source unit going to a Mcintosh mc420 that will be powering focal es100k in the front and es130k in the factory performance pods on the rear deck. I have a 6.5" bass pump that I plan on installing unless I can get a sub under the rear seat (tried a focal all in one sub and it sounded ok)
Last edited by cyclist on Feb 06, 2021 12:04 PM, edited 1 time in total.
Mike W.
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Re: In search for a better sound quality

Post by Mike W. »

SlickDizzy wrote: Jan 14, 2021 10:03 AM

One interesting observation I made is that the OEM front 4x6 grilles are absolutely horrid for sound quality. I replaced them with an aftermarket set of mesh grilles and the sound quality/imaging from the front 4x6s increased by an order of magnitude. So that may be something to look at if you feel that your stereo has good components but still kind of sucks.
I'm not the audiophile I once was, and cars are noisy enough I mostly want good functionality, absolute sound quality is really no big deal. But your observation above makes so much sense just looking at it I can't believe I never saw that potential before. Duh, you mean a solid piece of plastic with some holes punched in it isn't acoustically transparent? :shock: I can't believe nobody has voiced that before, at least not that I've seen. :up:
BillW in StL
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Re: In search for a better sound quality

Post by BillW in StL »

I have been messing with e28 sound systems on a budget for decades, and have some observations:
  • The speaker grill issue never occurred to me.
  • I have had luck concentrating on good speakers in the front run off the headunit amp, and clean bass running through a separate amp.
  • Component front speakers with a real crossover.
  • Bazooka tubes under the rear seat were common back in the day.
kirkandorules
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Re: In search for a better sound quality

Post by kirkandorules »

I just installed a pair of Infinity Kappa 4x6 plate speakers in the front, normally $200 but I found a pair for $97 on Amazon. Plate speaker with a real crossover. I'm no audiophile, but I also get very annoyed by bad sound - I think these are pretty solid, especially for the price. Driver side had to be mounted upside down, but otherwise fit fine. Be aware that they're 2.5Ω, which is a little odd.

Anybody retrofit premium speaker pods to a non-premium parcel shelf? Think that might be my next step. Seems like it would be straight forward, but curious if there is anything weird to look out for.
Philo
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Re: In search for a better sound quality

Post by Philo »

Is the plate steel or plastic ? I bought a set of speakers recently and they have a plastic backing plate that bends when you screw them in. I don't think I'm getting a good seal and front sound isn't the best.
vinceg101
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Re: In search for a better sound quality

Post by vinceg101 »

Philo wrote: Feb 04, 2021 2:17 PM Is the plate steel or plastic ? I bought a set of speakers recently and they have a plastic backing plate that bends when you screw them in. I don't think I'm getting a good seal and front sound isn't the best.
I worked this out when I put in my lower fronts (a/d/s/344is):
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I too was concerned about sealing up the footwells and came up with this:
-1/4" MDF backplate with foam around the back side to fill up (most) of the holes (you have to leave one at the bottom for the wires)
-1/2" spacer blocks top and bottom to hold the OEM speaker grille off the actual speaker
-Foam gasket ring around between the back of the speaker and the backplate
-Whole assembly is screwed into the footwell sheetmetal, the carpet piece covers the all of it (sorry I can't seem to find a final shot of it)

As you can here the issue is the hood release handle which barely clears the grille (it actually requires a little jiggle and light touch to get it past). This ties into another thread where Ben is designing an aluminum release handle; I requested it be designed to clear the speaker grille (but that's another subject).
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I will be refining this design as I roll through my current interior remodel (likely slimming the backplates and/or fabricating metal plates).

The 344is' are great speakers in this location and matched with the other a/d/s/ components, really fill out the system.
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vinceg101
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Re: In search for a better sound quality

Post by vinceg101 »

Speaking to subject of this thread:
I seem to gravitate to the vintage ('Old School' if you will) approach; it may not have been completely available in 1985 but it would have been something a past previous owner could have upgraded to a few years later. I have always had an a/d/s/ system of some sort in all my E28's, but this probably represents the pinnacle. This current system is in its' third or fourth iteration as I keep working out the kinks, but the present configuration is:
-Head Unit: Blaupunkt SQR88 Woodstock (cassette with front panel factory AUX input)
-Amps: (2) a/d/s/ PH15's (6 channel system split L/R)
-Processor: a/d/s/ 642iX
-DIN Assignment Module (DIN Splitter): a/d/s/ AC206
-Front Speakers: Low: a/d/s/ 344is, Highs: Orion PX concept.2 (crossovers are under the rear seats)
-Rear Speakers: a/d/s/ 300is (Bass & Tweeters with built-in crossovers)
-Subwoofer: Coustic Basspump 328 (the speakers were replaced with two 8" MTX's before I got them), with an a/d/s/ AC501 Bass Control Knob
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Each amp has conservatively 300watts, so that's a lot of power coursing through each speaker which is great since the a/d/s/'s live to be driven hard, even the small ones. The clarity and depth both the 344is' and Orion's create is pretty remarkable; I hear things in some songs I didn't know was there in the recordings (even analog recordings). The downside is it a very complicated system especially to balance; I have been working on adjustments ever since I put the first version of this system in.

I had a Kenwood Excelon X895 HU in at first when I had the single amp system (same PH15 and a 642CSi) and found the interface maddening; just way to complicated for driving not to mention the glossy screen was impossible in daylight.
I settled on the vintage Blaupunkt after doing some research as I wanted to return the HU to the cars' technological roots. Big upside was the AUX input which was perfect for an MP3 player and the 4 channel signal output. The Woodstock was in an elite group of HU's sold mostly in EU and was found mostly in Porsches of the day. (I have the SQR44 Nashville also which is identical only it's a 2 channel output, but it needs to find a new home).
I have been chasing some channel issues since this went in and I can't seem to figure out if it's internal to the HU or if it's rooted in the DIN-RCA adapter. I have one last test which is to try the high signal speaker signal wires again to see if it doesn't solve the issues. It's likely the HU itself, after all it's over 30 years old and has been knocked around a lot. I have a new Continental TR4512-UBA HU to try out in case the issue is the Blaupunkt. I hope not because I really like the style and cache of the old Blaupunkt, not to mention it's a cassette deck!

The whole system is getting dismantled (again) as I remodel the interior but will go back in much the same configuration. I am designing both a battery cut-off switch for the amp board (I believe it is the root of a rather persistent battery drain gremlin) and a cooling fan system for the amps. They tend to overheat and thermal lock after being run most of the day on long road trips (well, it is July and rolling through the CA Central Valley and Oregon with the outside temps around 100).

[I would be remiss if I didn't credit another board member Jay3 (Elguappo) for his tireless enabling/assistance in putting this madness together.]
kirkandorules
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Re: In search for a better sound quality

Post by kirkandorules »

Philo wrote: Feb 04, 2021 2:17 PM Is the plate steel or plastic ? I bought a set of speakers recently and they have a plastic backing plate that bends when you screw them in. I don't think I'm getting a good seal and front sound isn't the best.
It's a plastic plate, but it's fairly rigid and I did not notice any bending. I have some older Polk plate speakers in my 924 that have the same problem you describe, but these are a step up in terms of build quality. Granted, they're also brand new.
garageboy
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Re: In search for a better sound quality

Post by garageboy »

Wow. a/d/s... that's what my home audio is. Small world. :)
Mdreamer
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Re: In search for a better sound quality

Post by Mdreamer »

I know this is an old thread, but I have a question for those of you who have installed a subwoofer and an amplifier under the backseat, and I didn't really know where to post it.

For any of you who fall into this category, have you ever had issues with excessive heat being produced from having this set up? I'm intent on taking some long drives with passengers in my backseat. Would they complain due to this set up based on your experience? Also, does your equipment ever overheat due to the tight confines of the space?

Thanks,

Mdreamer
sixseries
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Re: In search for a better sound quality

Post by sixseries »

You could do a powered sub/amp combo, which I have, but I was underwhelmed by its power unfortunately and in retrospect would have paid someone to professionally install a separate sub and amp under my rear seat. I did the rest of the wiring myself
Mdreamer
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Re: In search for a better sound quality

Post by Mdreamer »

sixseries wrote: Nov 23, 2021 9:46 PM You could do a powered sub/amp combo, which I have, but I was underwhelmed by its power unfortunately and in retrospect would have paid someone to professionally install a separate sub and amp under my rear seat. I did the rest of the wiring myself
Thanks for your reply. I wasn't planning on going with a sub/amp combo because I've had experiences like the one you describe with those things in the past. I should have clarified that my question was for folks who have a subwoofer and an amplifier mounted separately.
sixseries
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Re: In search for a better sound quality

Post by sixseries »

You could put an amp that is just for a sub back there, which should be smaller. I used a special receiver that had a ‘mini amp’ built into it to power my 4 speakers so I didn’t have to use a separate amp for them, and I’m very pleased about that. I mean I’m running 4x6s so it’s not like a large amp for the speakers would be very useful
Blue Shadow
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Re: In search for a better sound quality

Post by Blue Shadow »

Put the sub amp on the rear firewall in the trunk next to the main amp. Put just the thump under your passenger's derrières.
Mdreamer
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Re: In search for a better sound quality

Post by Mdreamer »

Thanks, six series and Blue Shadow.

Putting the amp in the trunk sounds like it makes more sense, but i've been sorting through pictures of other's installs, and there are more than a handful with amps under the rear seat.

Are there any drawbacks to putting the sub(s) under the rear seat?
sixseries
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Re: In search for a better sound quality

Post by sixseries »

I think the main drawback would the size you are able to fit. There should be plenty of air and overheating is not really an issue since the amp is not under the seats anymore. Again, I would look to get the subs professionally installed due to the weirdness of the space and the bars that run across on the underside of the rear seat cushion
Mdreamer
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Re: In search for a better sound quality

Post by Mdreamer »

sixseries wrote: Nov 24, 2021 6:04 PM I think the main drawback would the size you are able to fit. There should be plenty of air and overheating is not really an issue since the amp is not under the seats anymore. Again, I would look to get the subs professionally installed due to the weirdness of the space and the bars that run across on the underside of the rear seat cushion
Excellent. Thanks again!
topher800
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Re: In search for a better sound quality

Post by topher800 »

fwiw. Here is a picture of my rear seat setup.

https://www.mye28.com/viewtopic.php?f=2 ... 2#p1475942
sixseries
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Re: In search for a better sound quality

Post by sixseries »

Looks great. Here's my set up. Was yours done yourself or professionally?

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