Rear seat wall speakers

[White Lincoln]

Has anyone used 5 1/4" bass speakers hooked to an amp and then to the receiver bass pre-out instead of putting a boom box in the trunk for bass? I was thinking of freeing up the room in the truck and using 5 1/4" bass speakers mounted on a 6x8 convertor plate in the rear side walls.

 

[AnthraxBird]

Honestly it would be a better option to put 6x9 or 8' woofers in the deck under the rear glass, otherwise you will lose the rear speakers.

 

[Kenz]

The location for the rear speakers under the windows is not enclosed, so very little bass can be made in that spot. When I first got my Cougar I put a pair of high end 6x8s powered by an amp. All it ended up doing is causing the trim to rattle in that area.
I ended up installing a factory sub box with an aftermarket subwoofer, it's fine for me. It provides good mid bass

Agree with @AnthraxBird about putting speakers in the rear deck behind the seats. That would require cutting and quite a bit of work but could result in good bass with the trunk as the enclosure

 

[theterminator93]

+1 for the factory sub box. While they are rare, if you can find a factory XR7 box, you can replace the factory 6.5" driver or even retrofit an 8" into it. It mounts under the decklid and doesn't sacrifice a ton of trunk space - way less than most sub boxes - and can fill the spectrum enough to give the door speakers a break.

https://forum.birdcats.com/threads/factory-jbl-sub-rebuild.177/ documents my journey.

 

[Irv]

I did the same thing Kenz did in my early years of ownership. You're not going to get anything resembling acceptable bass output from the factory rear speaker locations, and stepping down from 6x8" to 5 1/4" is only going to make it worse.

 

[Grog6]

I did car audio for years.
Get some good jbl 6x8 speakers for the factory spots, and a 12" sub for the trunk, and a good 5 channel amp.
You can't get bass out of 6x9's; I've destroyed many sets trying. I started car audio in '79.
Find some decent co-axial speakers with bass to ~200 hz, Add a jbl 12", and a beefy amp. It will sound much better.
I didn't want to fill the trunk with a heavy box, so I found a jbl 1214d speaker that only needs a 1.5 cu ft box. It's in a piece of 12" dia sonotube concrete form, less than 2 feet long.

 

[Kenz]

Baffles for the rear speakers could probably improve the bass response. I was going to try some but last I checked they wouldn't fit because of the limited depth of that location.

 

[Grog6]

Those speakers are all too small to produce bass. You end up smoking the voicecoil.

 

[Grog6]

Neat Fact: Our buddy Nick from MHS invented the copp,er former design, that helps this problem. RIP, Nick!

 

[White Lincoln]

Honestly it would be a better option to put 6x9 or 8' woofers in the deck under the rear glass, otherwise you will lose the rear speakers.

I already have 4x6 2-ways in the deck.

 

[White Lincoln]

The location for the rear speakers under the windows is not enclosed, so very little bass can be made in that spot. When I first got my Cougar I put a pair of high end 6x8s powered by an amp. All it ended up doing is causing the trim to rattle in that area.
I ended up installing a factory sub box with an aftermarket subwoofer, it's fine for me. It provides good mid bass

Agree with @AnthraxBird about putting speakers in the rear deck behind the seats. That would require cutting and quite a bit of work but could result in good bass with the trunk as the enclosure

I wish I could find an OEM box. The prices I saw where rather ridiculous due to the damage I saw in the pictures. That is preforable to me, but as mentioned, cannot find one. The ones I did find... "out of stock".

My Town Car has the OEM 6" sub under the deck and it is awesome. I could try to recreate that by fabricating a wood box... naaaa....

 

[White Lincoln]

I did car audio for years.
Get some good jbl 6x8 speakers for the factory spots, and a 12" sub for the trunk, and a good 5 channel amp.
You can't get bass out of 6x9's; I've destroyed many sets trying. I started car audio in '79.
Find some decent co-axial speakers with bass to ~200 hz, Add a jbl 12", and a beefy amp. It will sound much better.
I didn't want to fill the trunk with a heavy box, so I found a jbl 1214d speaker that only needs a 1.5 cu ft box. It's in a piece of 12" dia sonotube concrete form, less than 2 feet long.

So I found out some fun facts I never realized with my current system: (and why it sounds like shit)
The JVC head unit is only front / rear-sub pre-outs. My Town Car JVC has front / Rear / sub.
The head unit is NOT surround sound, the Town Car is.
The speakers are for the most part, okay - JVC 3-ways in the door / panel and 2-way in the deck.
The speaker sub is on JVC 4x50 AB... heck, the head unit puts that much power out on its own.
The woofer sub is a JVC 750x2

Geez.. what am I missing here? (other than its an old system.)

So I have been looking over some new equipment,
JVC 3 pre-outs, 5.2 surround (JVC KD-T925BTS)
JVC 1800 x 4 amp (BLAUPUNKT BPA-E604 4-Channel Class AB)
I will keep the current JVC speakers until I blow them up. I am not that wealthy..... and I can't hear anymore anyway.

 

[Big Scott]

I did a set of free air subs in the rear deck of my Turbo coupe. System sounded great and was well balanced enough that the lead guitarist of Anthrax would listen to their tracks they were working on in it. I'm finishing up the revamp of the system in the Cougar right now and also gearing up to do the one in the Focus. Cougie got a set of Rockford Fosgate Power T1682's for the rear sides and an impressive little Sound Ordinance M100-2 amp to drive them. I was getting everything removed in the non-back set area so the tint guy could replace the old peeling tint. Not an easy job with the cage but they managed to get it done properly and it looks great. I also removed the custom door panels to make things easier for them and went to town on adding the layers of sound deadening I failed to do before on the doors. I also sound deadened the crap out of the rear side inner and outer panels and stuffed moving blankets in the open spaces.

​

Finishing up a deep pour on the amp cover thing.

-Scott

 

[Kenz]

I already have 4x6 2-ways in the deck.

Did you install them? If you can post a picture I would be interested in seeing that. Do you think 6x9s would fit there? Even though they aren't that much different in size, 6x9s seem to make way more bass and have a better selection.

 

[Grog6]

Guys, if you want a sub box, the hardest part is getting the specs on a sub. Then you plug those numbers into a program, like this: https://subbox.pro/en/ (random web program).
That tells you how big to make the box.
Measuring a given speaker is possible, but a lot of work. Crutchfeld sells jbl subs.

 

[White Lincoln]

Cougie got a set of Rockford Fosgate Power T1682's for the rear sides and a......

-Scott

When I was researching speakers, the Rockford Fosgate Power T1682's came up the most in the "best car audio speakers". I ran through about 10 sites for best speaker and the RF speakers seemed to be the most suggested (that I would buy). Good choice. But I would not want to go as far as you did with a car stereo...

 

[White Lincoln]

Did you install them? If you can post a picture I would be interested in seeing that. Do you think 6x9s would fit there? Even though they aren't that much different in size, 6x9s seem to make way more bass and have a better selection.

I do not believe I ended up using the pegboard mounting plate. I used the 4x6 because it fit best of the speakers I was looking at. One down fall to the 4x6's I used, they don't put out a log of sound, as you mentioned AND they are 2-way coaxial.

 

[Big Scott]

I installed a set of passive radiators in the rear deck of Linky to help the subs pass gas... and a cone. The tweeter horns were never hooked up.




Audio Frogs for the win.

 

[White Lincoln]

Somebody is serious about their car stereo enjoyment...

Thanks Scott, I now have a complex about the "size" of my stereo system....

 

[Grog6]

I have some of that blue/black kevlar/cf material, also some red/bk I was going to do a hood with, but a me convinced me it wouldn't stick to steel in the sun.
You can buy thick kevlar honeycomb as radiator shields for flattrack cars.

 

[Trunk Monkey]

Nice work Scott!

What do you power all those speakers with? Let’s see you amps and wiring!

 

[Trunk Monkey]

Has anyone used 5 1/4" bass speakers hooked to an amp and then to the receiver bass pre-out instead of putting a boom box in the trunk for bass? I was thinking of freeing up the room in the truck and using 5 1/4" bass speakers mounted on a 6x8 convertor plate in the rear side walls.

5 1/4” speakers are not bass speakers. They’re mid-range at best. You want serious bass put a box in the trunk. I went with two 10’s in a sealed box, which make really tight bass. I wish I’d have gone with 12’s, but I’m ok with the 10’s.

 

[Grog6]

Guys, this is the sub I used:https://www.crutchfield.com/S-KYn6TJ9R74f/p_109GT1214D/JBL-GTO1214D.html


If you look at the specs, you see it only needs a small box, and doesn't fill your trunk. My sonotube 'box' weighs less than the speaker. I listen to everything, so a sealed box is a necessity; ported boxes are boomy, and it really only helps some rap.
Sinatra at the sands is a favorite.

 

[White Lincoln]

5 1/4” speakers are not bass speakers. They’re mid-range at best. You want serious bass put a box in the trunk. I went with two 10’s in a sealed box, which make really tight bass. I wish I’d have gone with 12’s, but I’m ok with the 10’s.

Oh geez... more complexes to deal with... "your sub is not big enough!"

If you trying to rattle the dishes in the china cabinet of your neighbors, 10 / 12' will do it but even 5 1/4 mid-bass will do an adequate job at getting a thump in your seat. Dayton has some nice 5 - 6" woofers.

It's like the headlight thing, you want bright headlights but who really suffers if you get them to your liking?

 

[Grog6]

I have a 12" sub on both the lr and mbr tv systems,lol.
You need to move air for bass. to get 5Hz, the lower limit on a cd, takes a 15" sub, or bigger, unless you waste a bunch of power.
I built speaker boxes for people in the 80's. I helped a mechanic buddy build a system for an escort, with a 15, 2 8's, and 5" mids, with tweeters on the a pillars. Garth Brooks never sounded better,lol.
All of my cars have had decent stereos, even the '63.
First sub I did was a 10" pyle,in a plywood box, and a 36w amp, with two jensen6x9's.
Speakers come down to physics. moving air makes sound waves,lower frequencies take more air, louder takes more power, the speaker compresses air higher by moving further harder. Boxes are more than resonance chambers; they also acoustically support the speaker cone. If you lose the support, it usually smokes the voicecoil. The AC impedance the amp sees depends on the box keeping the speaker from bottoming out. Ported boxes are known to do this below the port tuning frequency.
After 20 years of destroying cheap speakers, I finally found what works well, and lasts.

 

[Irv]

Oh geez... more complexes to deal with... "your sub is not big enough!"

If you trying to rattle the dishes in the china cabinet of your neighbors, 10 / 12' will do it but even 5 1/4 mid-bass will do an adequate job at getting a thump in your seat. Dayton has some nice 5 - 6" woofers.

It's like the headlight thing, you want bright headlights but who really suffers if you get them to your liking?

The mid-bass output from 5-1/4" speakers is not overcoming road noise inside an MN12 cabin at 50 MPH. If the output from four 6x8" speakers can't get the job done as far as bass is concerned, why would speakers with a smaller surface area defy the laws of physics and suffice? A 5-1/4" speaker isn't dipping below 45 Hz (which is already a huge stretch based on some manufacturers' dubious testing methodologies), and that 45 Hz output won't be strong because it's at the extreme limit of the speaker's physical abilities. More honest ratings would put the lower frequency limit at around 65-70 Hz. They're not going to thump anything, at least not until they get driven to the point of blowing up.

Also, sorry to say, a single 10" or 12" being driven at appropriate power levels isn't going to be audible beyond a couple of feet outside the car while it's running, at best. Nobody's china cabinets are getting rattled by that. You need orders of magnitude more displacement and surface area to achieve what you're describing.

 

[Grog6]

Mine was a pinto in a square box,lol.
I told dude with the 15 and 8's box to seal them, so they didn't share air. He forgot, so when the lighting hit in " thunder rolls", It blew both 8" woofers inside out! He was able to return them as bad, lol. That car had 3 120W Phoenix golds, 2 sets of 6x9's, 2 8's, and a 15.

 

[White Lincoln]

The mid-bass output from 5-1/4" speakers is not overcoming road noise inside an MN12 cabin at 50 MPH. If the output from four 6x8" speakers can't get the job done as far as bass is concerned, why would speakers with a smaller surface area defy the laws of physics and suffice? A 5-1/4" speaker isn't dipping below 45 Hz (which is already a huge stretch based on some manufacturers' dubious testing methodologies), and that 45 Hz output won't be strong because it's at the extreme limit of the speaker's physical abilities. More honest ratings would put the lower frequency limit at around 65-70 Hz. They're not going to thump anything, at least not until they get driven to the point of blowing up.

Also, sorry to say, a single 10" or 12" being driven at appropriate power levels isn't going to be audible beyond a couple of feet outside the car while it's running, at best. Nobody's china cabinets are getting rattled by that. You need orders of magnitude more displacement and surface area to achieve what you're describing.

Exceptional evolution. But here is my thinking and why I asked about subs in the side walls of the back seat. Ever since I have had the car, even with the OEM head unit / speakers, the rear speakers never put out that good of sound because they face each other and the sound does not seem to balance where you hear the difference in left / right, front rear and it sounds like one speaker. Even with the 5x7" I put in there on an amp did not make much diff. So I put the 4x7's in the deck and that helped a lot to bring out the sound differences. Recently, I tried using just the fronts and rear desk speakers and removed the side wall speakers... that is when I found out how crappy the fronts sounded and the rears put out most of the sound. Then I remembered I never hooked up the fronts to an amp because I only had two pre-outs, one for bass and one for the rear sides. No matter how I messed with combos this last weekend, I could not get a rich descent sound. That is when I found out the head unit did not have suround sound and putting all the amp to the rear really sucked. My new head unit came in today and I am waiting on the new amp. I have 2 - 10" in a box for the trunk, but was looking for an alternative to taking up all that room in the trunk. I may end up moving the amps to the back wall, and put in a 6" sub under the rear deck in a small box. Maybe I can weld together a box...

So Inv, you are very correct, but I was just looking for an alternative for the bass and since I am not looking to rattle the metal in my car when I drive down my neighborhood, the 4 5x7's and two 10" bass will work fine, just need to find a better way for the bass speakers.

And yes, I was exaggerating about the 10" bass out of frustration of the jerks that think I want to listen to their music while driving down my street. But an excellent eval none-the-less Irv.

 

[Irv]

The setup with the least amount of hardware that still produces respectable bass would be a 5-channel amp and one sub. It will still take up space in the trunk, but less than having a speaker amp, a sub amp, and two subs.

If I hadn't found the Alpine 10" loaded enclosure to wedge under my RSTB, I was going to build two small sealed 10" enclosures to put at the corners of the trunk behind the rear seat and in front of the RSTB.

The factory JBL sub box that Brandon modified is about the only readily available solution I see for having a suspended subwoofer enclosure. Otherwise, it's probably going on the trunk floor. What you can control from there though is the enclosure size. A number of companies make thin loaded enclosures which are typically designed to go behind the seat in a standard cab truck. Even if you don't get one of those, they can at least give you an idea of how you can construct one of your own if you use a shallow-mount sub.