Seeking suggestions for sound improvement for the rear speakers mounting divider frame on a Cutlass Convertible. The speakers face the rear into the well for the convertible top. They are mounted facing to the rear on the rear metal divider that is not solid (there are open areas). (See image.) The image shows the divider where the 6" x 9" speakers are mounted, and the other open areas of the divider that reduce the sound quality. The sound will be much improved if that speaker mounting frame divider is a solid, one-piece structure.

I've considered using a Dynamat product or possibly wood cut to fit. It can't be too thick since the clearance for the convertible folding top to fit into the well isn't much (1/4" or so). What material is used by the custom audio shops to seal the speaker mounting board for better sound? Once installed, it won't be seen from the trunk since the top well liner covers it up.

Thanks in advance.

Edit: I also intend to install similar sound dampening / sound improving material to the rear seat back metal frame divider (the other side of the speakers) which will essentially create a speaker enclosure behind the rear seat and the convertible top well.

 

Well the factory speaker location on convertibles is terrible. The sound is damped no matter what, but it is horribly damped with the top down.

I chose to use 6x9 speaker boxes that I can put on the back seat facing forwards (best sound quality), the rear floor boards facing upwards, in the top well ( sounds great with the top up as the well amplifies the sound and the rear glass reflects it forward), or remove them (using quick connects on the boxes) and stow them in the trunk.

 

Thanks Dennis. Yes, no thought (let alone engineering) was put into sound for these ol' ragtops. And convertibles are especially difficult to produce decent sound with the top down due to the open cabin ... like trying to produce sound on a boat.

I've considered all of the options (speakers in doors, speakers in front footwells, speakers in rear arm rests and top piston covers, box speakers, speakers under the front seats, etc., etc.). I want to keep it as stock appearing as possible. I have a dual voice coil hi-efficiency 4" x 10" speaker under the dash and it sounds remarkably decent, with Kicker 6" x 9"s hi-efficiency in the rear. (I have the AAR classic radio too that allows bluetooth streaming which improves the full-range of sound quality immensely.) I will add a small powered subwoofer as well, and will try 4" cube speakers tucked under the dash on brackets where they'll hardly be seen. The rear speakers do get muffled with the top down, especially too if you add the boot over the top. I know the sound (mostly bass) will be improved by closing the open rear speaker mount/divider. (The rear speakers on a convertible are inside a small triangle with open holes.)

 

Yeah, speaker locations on the convertibles is a disaster. I chose the arduous time consuming option. I removed the original panels and customized the installation.

 

I’ve learned a lot about stereo sound in a convertible over the past 30 years. Dunno what GM was thinking with the factory speaker placement.

I have the aforementioned 6x9 coaxials in boxes for the rear and 6” coaxials in the front kick panels, all driven by an amplifier wired in parallel. This drives a 2 Ohm total load and allows the rear boxes to be disconnected and keep the fronts amplified at 4 Ohms without the rears.

 

Just to fill in. I’ve had a ‘66 98 convertible for just about 40 years. Best I can recommend is what Norm did above in the rear quarters. I did the same and have a had a 6x9 in there.

Mine are mounted behind the cylinder covers and much less visible, but it’s the same placement more or less.

Sound is good to great, particularly if the speakers are backed by those foam boxes which push sound into the the cabin instead of the window voids. Also if you have a good strong amp like 50-70 watts per channel X 4.

The big downside of putting them there is that, depending on speaker size & depth, they can interfere with the top cylinders. My cylinders scrape the magnets, but haven’t worn through in 15 years or so. I figure the hydraulic seals will die first and I’ll replace the cylinders then. Until then, I have good sound.

Maybe suboptimal, but it works and sounds good.

Hope that helps
Chris

 

Yeh, those factory locations firing into the back seat was a total afterthought compromise. Best you might hope for is a little extra bass, mostly mid-bass. I get it though. In 1967, hifi audio wasn’t even really a thing yet.
It was inspiring to see that Vintage Chief put speakers in the rear panels. I figured if you did that, then you would be publicly hung by some on this forum. But why not? My panels are all cardboard repro’s from Legendary. If a hypothetical future owner doesn’t like it, then it’s easily remedied with new panels. However, if I go that route, I’m going to paint the grills to match the parchment interior. Less conspicuous that way.

 

I put SEVERAL sound systems in my 67 4-4-2 (1969-1973) and my 1972 4-4-2 (1976-1982). Factory systems were simply - blah.

 

Oops. I just looked at my rear panels. The only cardboard is on that small panel piece where the window crank is located. No room behind that for a speaker housing. Could probably put a tweeter there though. Maybe.
Even up through the 90’s most factory systems were crap. If I bought a new car, I’d always forgo the sound system “upgrade” and put that money towards an aftermarket system.

 

I'm wondering what size speaker you squeezed into the rear armrest, 4" or 6"? I'm willing to cut into the panel for the sake of good sound.

Steve

 

The rear panel speakers measure 5" (diameter) for the actual speaker itself. Total diameter is 5.25" with mounting enclosure.
The front kick panel speakers measure 6" (diameter) for the actual speaker itself. Total diameter is 6.5" with mounting enclosure.

 

I’ll date myself. My convertible’s sound system began with a Clarion cassette deck in the glove box in the 80’s. Anyone remember those?

I’ve surely done irreversible changes to the car. And I’m 100% comfortable with that.

These days I’m using 5.75” mid/tweeters in the front doors - 2 way speakers, if I remember what they’re called. Plus 2” tweeters cut into the metal dash long ago when the windshield was out. They fire upwards and help a lot, but its not worth pulling the windshield for sound. To normal people. I did it when I replaced the windshield after a crack or some other kind of damage.

I cut the inner door metal right at the base of the front corners and used cut a circular hole in the cardboard which sits behind the carpeting. Then used a soldering iron to poke a nice pattern of circular holes in the carpet cleanly, In an Abody you’re going to be a bit more space constrained, highly efficient 5” or 5.5” would work.

In the back there’s a 6x9 on each side in the arm rest. I cut oval holes fairly far forward in the metal, drilled a couple of mounting holes and the last time I redid the upholstery, my guy punched a nice oval circular patten in the covering to let the sound through the fabric.

I’ve got no problem with surface mount, but I like hiding the gear for the look & a little security. This 1 time, big cars have this one advantage over the A-bodies, one time, of being, well, bigger. Most of the time for restoration A bodies win the do-ability war.

One 10” subwoofer sits in the driver’s side of the trunk powered by it’s own amp for some bass response which is better when the top is up. The sub amp and separate 4 channel amp are on the opposite site outboard of the spare tire mounted to the replacement inner lining I made from construction grade floor protection cardboard covered with $2.00/yard car felt.

The big recent leaps were adding the foam sound directional boxes from Crutchfield ( I think…) plus speakers / amps that were good quality. Head unit in the glovebox so when I close it, the car looks like 1966, but sounds good. I mention the foam backing boxes because they were cheap and really helped. Good amps and speakers are less cheap.

Probably more detail than anyone wants to know. There’s more under my sign-in somewhere from back along the way, including a few pictures.

Chris

 

I love audio threads. If Vintage Chief ran into clearance issues, consider downsizing to the 4”. Or just check the mounting depth specs that are noted on every speaker sold. Back in the 90’s I caught onto the idea of keeping the sound stage in front of you. Properly imaged it’s like having the band on stage in front of you with the vocals pinned right in the center. Rear speakers were considered less important and usually there for “rear fill.” Gives you more adjustment with a fader and a little something for the occasional rear passenger. Bottom line…..you don’t need big speakers with big heavy magnets in the rear.

My 2 cents.

 

My Mom & Dad spun cylinders & danced to Big Band music on a Edison Victrola Phonograph in our finished basement. We also had a RCA Victor Standup Radio Console. I recall the first time they purchased a television - black & white, of course. Dad & I (sometimes w/ one of my brothers) were always heading to the Rexall Drug Store down the street with tubes in hand - plugging them into one of those big gnarly tube testers. My first record player was a single platter 45rpm phonograph. I thought I'd gone to heaven when I received a multi-platter automatic record player for Christmas one year - what an invention! By the time I purchased my first automobile (1967 4-4-2) in 1969, 8-track players had just come onto the scene. I'll bet I went threw six 8-track Beatles White Albums and at least four or five different 8-track players in that 4-4-2. The tape players would eat tapes like a kid eating Cheerios. Cassette players - well, another nuisance, IMO. Although, I do own ~1,200 hours of 1st/2nd generation soundboard cassettes from the likes of Frank Zappa, Grateful Dead, Jim Morrison, Hot Tuna, Jefferson Airplane, etc., etc. I used to trade shows. It made my purchase of a Nakamichi 680 cassette deck worth its money when I got to college. Now I can load 1,000 songs on a FAB & plug it into my 1971 CS convertible stereo.

 

Good walk down memory lane there Norm. Only thing I missed out on were the Victrola needles. I was born in 67 about 1 month after my car came off the assembly line. But I was the youngest of five and my oldest sister was 12 years ahead of me. I used to play her 45’s from the 1960’s on our massive TV/Stereo console. You know, the ones which looked like furniture with a TV in the middle, big speaker cabinets, and a recessed turntable on the top. Somebody bought me the theme to the TV show Batman (with Adam West) on a 45. I danced like crazy to that. I was 4 years old! Later she started getting 33’s and I can remember looking at her album covers when I was 5 or 6. Simon and Garfunkel “Bridge Over Troubled Water” was definitely in her collection. After she went off to college, my older brother picked up where she left off. He had so many awesome albums from the 70’s…..Van Halen, ELO, Journey, Foreigner, Kansas. If I could only keep one decade of music, I think I’d have to pick the 70’s.
“Eating tapes” made me laugh. Oh I remember those damn tapes getting eaten…8 tracks and cassettes. Cleaning the tape heads with alcohol on a q-tip and demagnetizing the heads with those special cassettes. The alcohol worked, but the demagnetizing never made a difference as far as I could tell.

 

Vintage Chief, I'm looking to do an install like yours. The speaker I'm looking at has a depth of 3" will that fit? How deep and what brand are yours? Are you happy with them?

Steve,

 

Steve - I don't recall the depth of the speakers. The front speakers are deeper than the rear speakers. I might venture a guess to suggest the rear speakers are ~3.5" to 4.0" in depth while the front speakers are ~4.00" to 4.25" inches in depth. I am very pleased with the sound quality - no issues and they take everything the stereo has to put out. Memphis makes some decent quality car audio speakers. I installed mine several years ago, I'm not certain if the exact model is still available but they have a decent selection to choose from.

Memphis Car Audio

 

Steve,

Note that Norm's speakers are nowhere near the lift cylinders, so there should be a lot of space behind them. Just measure the top of the arm rests to see approximately how deep a speaker you could install in that location.

 

Correct - I placed my speakers as far forward as possible from the lift cylinders. I will note there is a slight backward pitch to those cylinders when they're retracting; IOW, they don't simply move in & out. I think I also needed to remain below the depth of the armrest ashtrays. In any case, you should have plenty of room - take good measurements when you remove the panels and do a couple of dry fits - you'll be fine.

 

You can safely mount up to 5.25" shallow-depth speakers in the top portion of the rear piston covers and they sound great if you install a higher end speaker - I have Morel coaxials in mine.with 1" spacers to ensure complete piston clearance.

For a divider, I simply used a sheet of sound insulation behind the seat. All works well.

 

Thank you all for the feedback. One more thing to tackle.

Steve

 

It's worth pointing out that a lot of things we take as foundations of cars, power locks, power windows, A/C, decent stereo, were all getting started in the 60s and early 70s. Stereo was just coming into the A bodies in 70. Chevrolet made the radical decision to put stereo Left and Right and a fader for front to back. The Chevelle, etc, had speakers in the dash, off the windshield, and the itty bitty speakers did some freaking contortions to get in between the pad and the panel. Olds, however, never had to move those speakers if the AC showed up (unlike a Chevelle that needed the space where the center duct went for the speaker) so it had one speaker in front, which means one speaker in the back. That's ok for a hardtop, but they put the rear speaker in the ragtop in the only place it could go. I think it was decent engineering when you look at everything in the picture. Sure, it sounds bad with the top down, but who cares, the top is down!

 

that's why at least for the ragtops, upper rear piston mount speakers make the most sense - no loss of sound path with top up or down. Combine them with a set of front kick panel speakers and you're set for sound!

Aftermarket actually makes a dash- mount stereo replacement speaker, though it's only two tiny speakers mounted side by side to a flake-board base shaped to fit the factory opening. Problem is the speakers are horrible, under-dash maneuvering room is basically non-existent for purposes of removing the old for install of the new unless you remove many other things to make room. And if you elect to install an aftermarket AC (like Vintage Air), the dash speaker would have to be permanently removed anyway to make room for the system install.

 

I spent a royal fortune on the sound system for my '69 442 convertible. It's a modified 400 big block with a fantastic sounding exhaust note.

OK, not productive to the conversation.

 

Those exhaust note(s) - treble or bass clef?

 

Flowmaster

 

I have a 72 Cutlass Supreme droptop and though I have the 6x9's mounted behind the rear seat. I put in kickpanel speakers along with the center dash speaker. But then I also added stealth base/tweeter speakers under the bucket seats. These worked great increasing the base and overall cabin sound. You do have to slightly file or grind a small portion of the seat track but it does not effect the seat slide operation. They are supplied by Custom Autosound and run about $220.00
WARNING ! Due to the base vibration under the seats, your Wife or Girlfriend might want to ride around with you more often ! LOL!

 

RE: WARNING - Years ago I had a Lotus Esprit and took my girlfriend for a 1 1/2 hour ride. She said she was feeling a vibration in her seat that was that it was driving her crazy. It turned out the PS rear wheel was slightly bent a bit. Fortunately I was able to resolve the situation when we got home. Should I have sent the wheel out to be repaired or not was the question.

Steve

 

Question is was it driving here crazy in a good way, or bad way ? !!!!

 

She wasn't pleased that she could not "scratch the itch" at the moment. A solvable problem for sure.