1967 Radio & Speakers

[Big_John]

I'm assuming that custom audio's DVC speakers are a way to get stereo audio from a single speaker - a speaker with separate connections for a left and right driver.

Or maybe it's their "Dual Speaker" - "Custom Autosound's dual dash speakers provide great stereo sound from your classic car or truck's factory mono speaker location."

That's it exactly. It let's you put a 2 channel speaker in the stock location. Each voice coil is fed separately from left and right channels and the woofer is fed (I believe) from both channels.

Sound wise, it's a great alternative to cutting up door panels or whatever in a convertible where there isn't a good spot for 2 rear speakers. The channel separation argument goes away when you are driving a noisy convertible. An alternative is mounting 2 smaller speakers on a 6x9 plate. I did this with the front of my '70 vert. (4x10" stock speaker size)

That works OK, but bass is lacking. I've had to add filters to block the lower frequencies to these speakers otherwise they distort a bit on bass notes.

The 6x9 dual coil speaker in the rear doesn't have that issue, although I did add low frequency filters to that too as I have a powered sub woofer under the rear seat that takes care of bass.

Honestly, all of this is kind of subjective. You take an old car with rattles, minimal sound deadening, noisy exhaust etc. and then worry about the fidelity of the sound system. Unless you are really concerned about how it sounds sitting still, most of the improvements have minimal results once you hit a certain level. Put some old ears in the mix (like mine) that have been abused over the years from racing, shooting, loud music, and factory noise (again like mine on all counts) and even more diminishing returns on high end stereo equipment.

"Dual Voice Coil" = Co-Axial speaker.

No, that is not a "co-axial" speaker. Different animal.

Co-axial or tri-axial speakers do have different voice coils for different frequencies, but have no provision for separate left/right channel. Dual voice coil has one voice coil for each channel. The dual voice coil isn't meant to be used with one channel factory radios. But, used with the stereo conversions or aftermarket stereo radios, they work great for installation in stock locations where you don't want to cut or add more speakers.

 

[Big_John]

I don't believe you are understanding the situation. The front dash speaker is not a "stereo speaker", although having multiple speakers in one assy. All are on the "same channel" from the same input source.. The pictured 6x9 speaker, for illustration purposes, is what used to be termed "tri-axial" speaker. Usually sold in pairs for the rear deck.

I think you are thinking "stock" while the rest of us are thinking "aftermarket stereo" in one form or another.

 

[CBODY67]

I think you are thinking "stock" while the rest of us are thinking "aftermarket stereo" in one form or another.

Actually, I'm thinking "both", and how they can inter-mingle.

When I was researching how to get a "stereo" 4-speaker upgrade on my '77 Camaro, from the factory "sub-standard" stereo, with one channel in the rear and the other one in the front, the possibility of the aftermarket 2 speakers in one location appeared as an allegedly viable option. I immediately saw that as "not what I wanted", desiring more physical speaker separation than that, although it would be easy to add a 2nd rear speaker. Some just added an additional rear speaker and forgot about the front speaker, but I didn't want that either. So, when I finally installed a Blaupunkt 4-speaker radio, I put some 6x9, rolled suspension dual-cone rear speakers in the back and two Pioneer 3.5" rolled-suspension speakers in the front. Putting the front speakers facing down from the lower outside edges of the instrument panel structure. Not ideal, but speakers physically far enough apart to get some degree of separation. With the front speakers being unbaffled, in open air, it was tricky to get the f/r balance good, so the front speakers weren't over-driven to match the rear speakers volume level. Not great, but decent for me. I did not and do not subscribe to the over-powering bass notes, so that is a short-coming of my speaker placement.

In 1979, Firebirds went with a 4-speaker system, with two 3.5" front outboard speakers in the front. I later found out that such a system was scheduled for the 1970 Camaros, too, but deleted prior to the start of production. Pioneer also had some satellite speakers which could be placed on the top of the instrument panel, but I opted not to do that.

Prior to this, I changed the radio in my '70 Monaco Brougham from an AM w/rear speaker to a factory-from-Chrysler OEM AM/FM Multiplex w/2 rear speaker set-up. As if a miracle at that time, I had all of the parts within ONE week from Chrysler! Only thing I had to build was the wiring harness going to the rear speakers, but that was no issue, using the better speaker wire of the times. For the front outboard speakers, I hung them off of the lower outboard edges of the instrument panel. With the center speaker in the mix, that worked pretty good and had a stereo separation that was good. Such that I could image the sound off of the windshield.

To me, the "magic" of stereophonic sound is the separation of the recording microphones and the separation of the later sound reproduction mechanisms. Getting the "ambience" of the lh channel sound in the rh channel sound, and vice versa. What some termed "concert hall realism", back then.

For the side-by-side 3.5" front speakers to work, they need to be angled away from each other, to spread the resultant sound, then letting it bounce off of the curved and slanted windshield to better mimic the OEM speaker separation situation. I considered doing that, using a 4x10 speaker shell, but didn't have the expertise to make that happen, for my Camaro.

The other option for the Camaro was "door speakers", but with factory power windows, not possible, they claimed. There were lots of add-on front speakers in the earlier 1970s, even some wedge-shaped ones for under the front seat, using 4x6 speakers in a wedge-shaped housing.

I was watching what the aftermarket was doing as to speakers and factory-look radios well into the 1980s. Including their "innovative" replacement speakers. At the time, I considered them "band-aid" fixes, at best. Not what I wanted to do, although some might like them.

At home, in the later 1960s, I experimented with setting the speakers of my Motorola stereo phonograph to aim them upwards to bounce off of the walls and ceiling, for a wider spread of sound, rather than having them aimed at me, where I'd have to sit in the center of their aims to get the best stereo experience. Then came the first Bose "direct, reflecting speakers" in about 1970, for a "wall of sound".

Unfortunately, convertibles were not about a good stereo experience, back then. Too much "other" sounds and the lower output amps of the factory radios were two detracting items. In the later 1980s, the LeBaron Convertibles had a factory 4-speaker-location stereo system that had enough guts for stereo, with the top down, at 70mph if the volume was turned up.

Enjoy!
CBODY67

 

[Tall_Texan]

What I am planning to do, since the car already has 4 cut outs in the door, is run the 4 door speakers (in parallel or series) on the front channels and use a DVC speaker in the rear seat position on the rear channels. I understand it won't be the same as having 2 independent rear speakers, but with the Convertible aspect seems like the best alternative.

Will let you know how.it works out once get everything installed.