The why:

I bought my C6 convertible a few months ago. I wasn’t too impressed with the stock Bose setup and I knew I wanted to install some sort of audio system ....... but wasn’t sure what.

What I did know ..... I bought this car as my weekend "getaway" car and did not want to install audio equipment in the trunk because I wanted to be able to use the trunk for luggage during road trips.

I was originally just going to swap out the 3.5 (front doors) and 5.25s (rears) to make the stock Bose setup sound better until I figured out something else,

However, when I was replacing the door 3.5s ......... I realized the passenger side door subwoofer was not working ... since I'm always on the driver side .... I had not notice it was not working until that moment.

Now what?

After doing some research to see what other people were doing for subwoofers with C6 convertibles, it looked like most were putting subs in the trunk “or” going with 8 inch subwoofers behind the seats with 6.5s and tweeter components in the doors

Not satisfied with these options, especially since I just installed some Polk Audio 3.5 and 5.25s front and rear speakers, I decided I would “try” to upgrade the door subwoofers.

The problem was ....... I wasn’t able to find a 10 inch shallow mount subwoofer that was designed for a free-air application. Most shallow mount subwoofers are designed to be used in a small sealed subwoofer enclosure.

The plan A:

I eventually settled on some MB Quart 10 inch shallow mount subwoofers that are inexpensive enough to “try” my door subwoofer experiment. Even though these subs were not designed for a free-air application, I still decided to give it a shot.




I also bought an Arc Audio mini 4 channel (125.4) amp and installed it in the passenger side foot well (where the Factory Bose amp is located).

I used 2 channels for the front and rear speakers (parallel) and the other 2 channels for the door subs (I had totally given up on achieving any type of proper sound stage at this point in this experiment).



The results:

It actually didn’t sound bad at moderate volume levels, but when you cranked up the volume, the doors subs would bottom out (making a popping noise). I wasn’t too surprised by this because I knew these subs were not designed for this type of application.

Still not satisfied ..... I figured I would just leave it alone and live with it until I figured out a better solution.










Then someone posted this picture:



This was the answer I was looking for .... a good subwoofer setup in a C6 vert without using the trunk.











Plan B:







Box finished (covered in black carpet) below





stay tuned

 

The saga continues:

I’ve had numerous audio setups over the years …. some in hardtop cars …. others in convertibles.

One thing I know:

The most difficult cars to get good sounding sub bass from … are convertibles

Well, when I say “good sounding bass” I’m talking about how the bass is heard and felt by the driver and passengers of the convertible is concern …. Your neighbors and other cars around you may disagree.

Bass in a convertible (with the top down) does not have anything to reflect off of and allows bass to escape from the car without being felt as much as if you were listening to the exact same setup in a hardtop.

Obviously …if you have more subs and more power …you have more subs and power.

But in a convertible .... are you enjoying it … or just annoying everyone else around you?

Knowing this … I still wanted a subwoofer set-up in my convertible (see above) but I also was trying to think “outside of the box” yes ….. pun intended.

So with my C6 convertible, I decided I was also going to try tactile transducers.

For those who don’t know, a tactile transducer is a device that "shakes" similar to a subwoofer (minus the cone).

The “theory” is low subsonic frequencies are felt more than heard.. so a tactile transducer in “theory” gives you that big bass "feeling" and are sometimes called “silent subwoofers”.

I’ve known about tactile transducers since the 1990’s, I’ve always wanted to try them in a convertible so:



the dollar bill is to give you an idea of the size.





This is another “experiment” but reviews I’ve read regarding tactile transducers, most agree that they work better to compliment an existing subwoofer not as a replacement for a subwoofer.

Now ....with the 10s firing at the back of my head and the tactile transducers shaking my butt ... I can’t wait to get this all up and working and try it out.








BTW – I fired up the new sub box today for the 1st time … I’m very happy with the sound it’s producing.

I’m still not sure if I’m going to keep the MB Quarts or go with something a little higher end.

The MB Quarts are recommended for a minimum of a .4 cubic foot enclosure with a .65 cubic foot enclosure being optimal for a flat response.

I’ve figured out the enclosure I’ve built is about .5 cubic foot enclosure per chamber (adequate size enclosure for the MB Quarts I have).

If anyone knows of a 4 ohm 10” sub that works well in a .5 cubic foot enclosure please let me know.

The only other subs I’ve found that are rated for under .5 is the pioneer 10 inch shallow mounts (.45 cubic foot sealed)

 

I'd love to put my 10" subs right there behind the seats. I'm jealous

Here are some 10" subs that are spec'd for smaller sealed boxes. Those rated for 0.6 cu ft may work well in a slightly smaller box with some filler.

Alpine SWR-T10: 0.6
Kenwood Excelon XR-W10F: 0.6
Pioneer TS-W2502D4: 0.35-0.7
Diamond Audio S104: 0.6
Alpine SWR-1043D: 0.5-1.0
Pioneer TS-SW2501S4: 0.35-0.7
Kenwood Excelon KFC-XW1000F: 0.6
Boston Acoustics G310-44: 0.5

Of course, you'd also need to check mounting depth to see if they'd fit into your enclosure.

I haven't heard your MB Quarts or any of the subs listed above, so I can't comment on how they'd compare. I just did a quick check on Crutchfield.

 

I have mixed feeling about the MB Quarts I have.

I’m surprised that they are producing the lower frequencies as well as they are. I didn’t think they would be capable of going that low in such a small enclosure. I do have polyfill in the enclosure and I’m sure that is helping.

My biggest complaints about the MB Quarts are they are not very efficient and the excursion is not that great, however that seems to be common with shallow mount drivers in general.

I’m pretty sure I can fit normal size drivers in this enclosure, I’ve look at some of the drivers you’ve listed above ... plus also I have considered Polk’s MM1040 (.66 cubic ft) and I’m also considering the Pioneer TS-W2502D2 (.6 cubic ft) but the pioneers are almost 7” mounting depth and not sure if those will fit.

The other thing against the MB Quarts in my setup … I’m also considering getting a mini Arc Audio 500.1 for my subs. The Arc is rated at a 2 ohm mono load …the Quarts are 4ohm DVCs (4 ohm mono or 1 ohm mono options for the pair) and are not a good ohm match up to use the Arc Audio 500.1 to its full power.

Plus, I still have to decide if I’m going to keep the tactile transducers in the setup. I want to get them working in conjunction with the 10’s before I make a final decision on that. I’ve only had them working without the 10’s thus far.

Thanks for the subwoofer suggestions … I think I will take another look at some of those you’ve listed.

 

I have the Polk MM1040s, and I think they sound great. They hit hard and go low, but I've been running them in a subthump box powered by the sub channel of an Alpine PDX5.

 

 

Take a look at the Arc Audio 10, great sounding, great output, 5.5" deep, I use them in my Vette audio packages and love them.

For those wanting an all out sub and willing to accept 8 lbs per sub added weight the new Arc Black Line subs are killer and only 1/4" deeper.

The 500.1 is sweet little sub amp, 500 watts from 3.2 lbs, Class H so superior to any D class amp in sound and low power consumption, best little amp I have ever heard.

The 125.4 and 500.1 fit into the stock Bose amp location, I have shipped many pairs with my Vette systems packages.

Nice enclosure by the way
Rick
801-829-4997

 

it's still under construction …but here is a picture to show what direction I’m heading.



Stay tuned

 

So, on the transducers, do they feed on ohms just as a speaker would? So you have 2 subs plus 2 transducers, feeding off a single amp? Seems that would have to be 1 ohm stable for two 4-ohm speakers and two 4-ohm transducers? I always wondered about the load thing with those, so how's it working?

 

Four 4ohm loads can be wired as two parallel sets (each seen as 2ohms) in series for a total load on the amp as 4ohms. The only potential problem is that each sub/transducer will essentially only get 25% of the amps rated output.

 

Here is what my final system is going to consist of:

Arc Audio KS 300.2 to Polk audio MM6501 (2 ohm rated) 6.5 and tweeter components in the doors (amp running 2 ohm stereo).

Arc Audio KS 1000.1BX to a pair of Polk audio MM1040 (4 ohm) 10 inch subs (amp running 2 ohm mono).

I’m using 2 channels of the mini Arc Audio Amp to the 4 ohm transducers (4 ohm stereo load).

I’m using the other 2 channels of the mini Arc Audio Amp bridged for the center channel. <- Note: I know most people disconnect the center channel because it interferes with stereo separation.

What I’ve done is created a mono center channel band pass with high and low filters. The highpass is at 400 Hz and the lowpass is at 2,000 Hz. This is roughly the human voice frequency range. It has “helped” to center the vocals without destroying stereo separation.

I’ve done a lot of listening to my setup with and without the center channel and the transducers in the mix. I’ve found the trick is to setting the gain levels on both to where you "don’t" notice that they are there “but” you do notice if you turn them off.

As far as the Tranducers:

The Aura bass shakers are what I originally looked at. I remember these being marketed to convertible owners in the car audio magazines in the early 1990’s. My first instinct was that transducers were a “gimmick”, but since they are still around after 20 years, I figured gimmicks usually don’t last that long.

After doing some research on the internet, I went with the K-woon units because the reviews I read indicated that the K-woons unit were better than the Auras in frequency range (less of a one note wonder). Not to mention Aura bass shakers “pros” would not fit (too big).

On that note, the K-woons are a tight fit and not ideal if you need to have your seat all the way down to the floor in its lowest position. As long as you can live with your seats being about an inch higher than the seats lowest setting, they are fine. I’m 6 foot and the seat height works for me.

How do they sound / feel?

I experimented with all kinds of various combinations

I tried the Polk audio 6.5 and tweeter components in the doors with just the transducers running on the arc audio mini amp.

It sounded so much better over all than when I was running the 10 inch MB Quarts in the doors with the Polk 3.5s.

The 6.5s in the doors went low enough to where the K-woons gave the illusion that I had a subwoofer (hard to describe with words). This type of setup is what some of the Mazda Miata guys run, and I now understand the appeal.

As far as your question:

“do they feed on ohms just as a speaker would?”

Yes, but I wouldn’t recommend sharing them with the same amp as your subs. I tried it briefly, and you really need them on their own amp so you can dial them in correctly. Set properly, they add to the experience, but too much power and they feel unnatural and rather annoying.

 

Considering the conversation is about gizmos that vibrate your butt cheeks, that has to be the quote of the year right there

 

Yeah...... I didn't want to go there ... but you are on the right track

 

 

I'm very interested in that box. Can you build another or did you make/save templates/measurements?

 

I am searching for one too and the two vendors I have contacted are not available to make one. Summer is coming quick.....

 

I’ve been getting about one request a week asking if I could build another enclosure.

The truth is:

I really didn’t even want to make my own enclosure, but I realized …. to get what I wanted ….. I needed to make it myself or pay someone to make one for me.

The enclosure was very time consuming to build and was difficult getting all the measurements right so that the convertible top operation wasn't affected .... all this while trying to keep enough airspace for two 10 inch subs was a real pain in the a$$.

I'm very happy how the enclosure turned out, and I really appreciate all the inquires ... but unfortunately, I just don’t have the time to make another.

 

Just thought I would post a follow up.

I took the car for an extended drive on the freeway with the top down.

Verdict: I’m very happy with the setup and I’m glad I decided to keep the center channel and tactile transducers.

The center channel:

The center channel is doing exactly what I was hoping it would do. It has helped to raise the sound stage and added more midrange volume.

Also, since I’ve limited the frequencies of the center channel to 400 Hz - 2,000 Hz it’s not interfering with stereo separation.

I know the ideal situation for any stereo setup is path length equalization of a pair of speakers. However, there is almost always some tradeoffs and compromises while trying to achieve this in a car. I know what I’ve done is a compromise, but I’m happy with the results.

The tactile transducers:

What finally made me decided to keep them is I downloaded some test tones. The subwoofer enclosure I’ve made sounds good at about 40 Hz and above (with the Polk MM1040 subs I recently installed) but rolls off sharply below 40 Hz (most likely due to the airspace volume of the enclosure being a little small at .5 cubic foot per chamber). The transducers really shine at about 30 Hz to about 50 Hz.

The last post on the subject might lead some of you to believe that the transducers just “vibrate”, but they do produce audible frequencies and can be heard up to the lower midrange frequencies if hooked up full range.

I’m still not sure if I would recommend transducers to others (the jury is still out on that) …. but they are a cool "novelty" (if nothing else) …and they have helped to add some of the “punch” that is loss with the convertible.

 

So does your vert top lid close as it should? Was yours a manual or motor top? Awesome install and fabrication. So to transduce or not to transduce, which works best?

 

Thank you

Yes, the lid and top closes as it should (power top).

This one is a little harder to answer.

Tranducers tend to be more common and popular with home theater enthusiast and gamers. I now totally understand why … because of the difference between special effects with movies and video games …. verses musical bass notes playing music.

Having the transducers while watching movies … would be way cool…. But musically …. I have mixed feelings …. some songs they rock and I love the effect …. others songs not as much.

I now think I should have added a volume level controller that is accessible while driving …. so I could adjust them on the fly …. I think this would make them better.