This one is probably coming from way out of left field, but here goes:

I currently have a Kenwood 308U head unit, CDT 6.5" subs in the sail panels, and some Kicker convertibles in the doors. I've been kind of bothered lately at how much better some of my friends' vehicles sound with 6.5" speakers than mine (we're talking 15-20 year old BMWs and my GF's '09 Corolla). I found (did this when parked of course) that when I put my head near the bottom-left-hand quadrant of the steering wheel, basically starting to get into the footwell, the bass output is phenomenal. It in fact seems like the ONLY place in the car that doesn't have good audible bass presence for how strong these speakers can push is right at around head position when sitting in either front seat.

I've toyed with the idea of sort of "porting" the doors and sail panels back into the cabin in an effort to get better bass response, but even if possible it seems like a tremendous (and destructive) undertaking.

Barring that, I've wondered if there was any sort of way to mount these speakers angled to project so the driver can actually enjoy the full sound, not just my feet. Is my only easy option to sort of shem the speakers on a per-corner basis with flat washers? Or is that in itself a bad idea as well?


Just kinda free-thinking in all of this. I don't think this car should sound as weak as it does for having 4 very-capable 6.5" woofers pushed by this head unit and even a Monsoon factory amp...

 

I find it a little hard to believe there is THAT much difference in perceived bass response just by raising your head up a couple of feet. True sub-bass is perceived as non-directional. What frequency people start to perceive bass as being directional is debatable, or at least different for different people. Mid-bass in the 80-300 Hz range coming from the Monsoon sails can probably be considered directional bass by most people.

While you could expend a lot of time, money, and effort trying to apply the same guidelines for speaker positioning that home audio enthusiasts use, but in a car, with custom panels, etc, trying to squeeze a little more blood from a rock... I would suggest if you want more bass, get more power. Bass takes power, way more than midrange or high freqs take to reproduce. ...and get yourself a real 10" sub to make some real sub-bass output, in the 25-100 Hz range.

 

The difference is definitely there in a big way. I wish there was a way to adequately capture the difference with a camera. I'm not sure I could even properly capture the difference by lugging out my laptop with one of my microphones and recording from different listening positions.

The four of these speakers together produce enough output, even down to the 30-40hz range, to fill the cabin more than enough; with a properly normalized sound file (I use a 16gb thumb drive to a USB input for all my music, btw), I can't really take it even to about 50% volume output before panels start buzzing and rattling, and at the normal listening position the bass is only mehr, although I can feel significant vibration in the seat for some of these songs (for reference, some test tunes I use are "808 Kick Drum" by DJ Laz and "Get Low" by Bass Mekanik. Lots of steady sine wave bass, so crystal clear tone). I can take the volume down about 10%, then move my head to where I described above, and the apparently bass volume and clarity is significantly higher than before I turned it down.

The door panel speakers in particular are about equal to where your shins are when seated, and point directly at the center of the car. The speakers in the sail panel aren't much better in that they both pretty much point right at each other, but at least they sit higher and slant kind of forward.

I suspect that it's primarily a phase-cancellation problem, but my current Kenwood doesn't have any provisions to introduce micro delays per channel or per front vs. rear to fine-tune for the listening position, and honestly that'd be much more expensive to get a new head unit than testing my idea of trying to shem the speaker mounting points to angle them differently.


I'm gathering that maybe no one has tried this particular approach before.

 

actually you wanna do the exact opposite of "porting" the doors, what you wanna do is get some sound deadener like second skin or dynamat or anything like that that can get wet and won't grow mold (because some water does get inside the door) and line the interior of the door (the inside side of the outer door skin) making sure NOT to block the weeping holes in the bottom of the door (you don't want it to fill up with water) then sound deaden the area that the clear plastic covers (behind the actual door panel), sealing the inside of the door, the idea is to make the door like a box for the speaker.

Something else worth mentioning is regarding tweeters, in my experience they do there best when they fire toward the windshield, see attached picture of early 90's civic door panel, this was the "premium sound" factory option, my old civic had it and on the accords they had there tweeters mounted in the upper dash, not as good IMO but better then having them down low.

See other 2 pics for a reference of what i'm talking about with sound proofing the door (except modify the blue door image and close all those openings they left open, well as much as you can without effecting the door handle mechanism).

 

My formula has the same issue. Good speakers, but the bass is crap unless you are ear level with the speakers. I added a 10" sub and it got a whole lot better.

Have you left the volume at 50% and changed your listening position? I used to drive a 1998 Cadillac Seville with the Bose 4.0 sound system in it. It did this very weird thing where at low to mid volume, it had bass to spare, but the louder you made it, the less bass it had. I noted the same damned thing with a bose equipped camaro that I had. Wondering if the amps that GM uses have some kind of internal fail safe that reduces bass under high volume.

 

as mentioned before, BASS takes MORE power to create then highs so as you turns the volume up, while the bass does increase it increases at a slower relative rate then the treble which is why bass appears to "drop off" at higher volume levels, you will see this in pretty much any system, they all have a "sweet spot" in the volume and above that the highs get louder quicker then the bass does, it has nothing to do with what factory amps have or anything like that. I can see this in my own system and the only factory part of it is the speaker wires (since my doors and sails are powered from the HU for now).

 

While some Dynomat may help seal the doors up a bit for some marginal improvement towards making them something closer to a ported enclosure, the real advantage is in damping vibrations and reducing resonance on large sheets of metal. Other than that, DR and I are in complete agreement.

I know you've done all these tone tests, and while your bass tones may "feel" loud enough in isolation, with only 20WRMS or whatever your HU puts out, they almost certainly aren't proportionally as loud in measurable dBs than your mids and highs after a certain point.

You can mess around with tilting speakers, getting custom enclosures, and phasing chicanery... or just get some more speakers and more power to comphensate for the perceived shortcomings.

• Get a 10" hatch sub to overlap sub-bass freqs into the operational range of your sails. This will "blend" them more subtly into the soundstage. Your 6.5" sail cones can't come close to what a 10" with 250-300WRMS can produce at 40 Hz.
  
• Get some modest fill speakers going again your hatch. This will help diffuse perceived right/left directionality. I know people on this forum will tell you they are worthless, don't bother, etc... but OEM designers had them in place to cope with exactly the type of issues that picky audiophiles like yourself complain about!
  
• Drive your doors and hatch with an external amp with 75 RMS or more. This will allow the bass coming out of them act more proportional wrt the mids and highs coming out of them. It will also allow the use of external crossovers without suffering a noticable power loss and allow for a steeper cutoff slope in your components.
  
• CDT actually made a set of additional tweeters that could mount on your dash to provide exactly the effect that DR was describing. I haven't ever tried them myself, but I already have done the first 3 suggestions and I'm happy. It's called CDT "StageFront". Kee can sell you these.

http://www.cdtaudio.com/upstage/up2100i.htm

 

While I fully appreciate that adding a single larger, high-powered speaker can accomodate my needs, I don't agree with this notion that 4 6.5" speakers absolutely can't fill this space for how much I'm pushing them. We aren't talking about OEM speakers here, these are Kicker and CDT woofers designed to at least respond down to like 35Hz, and although the Monsoon amp isn't competition spec by any stretch, between the power output of the head unit itself and that amp the speakers are getting plenty of power for my needs in this contained space. Like I mentioned, I can't really push it past 50% before it's too loud (like 18-20 out of 40 in the volume scale of my radio).

I can compensate for the audible volume disparity between lows and highs by engaging the bass booster feature of the radio as well as using the radio's EQ to drop treble levels moderately as well as mid-range levels very mildly. Even though one 10" can produce more audible low-freq sound with less power, multiple smaller speakers should be able to achieve similar if not identical perceived levels with proper power as well (to a point at least, and I don't believe 6.5" is below that threshold.)

The only explanation that seems to make sense to me is a negative resonance well right around where the driver's head is, given that I can move my head around even the door speaker without getting closer to it but still hear a huge difference in apparent low-freq volume.


I do think I'm gonna try some sound deadening and to isolate some rattle points, maybe I can at least push them a little bit further than now to bring it to a satisfactory level after tweaking the EQ a bit further...

 

I can see that. Still, there must be something with how GM diverts the power because my Mach 460 in my Cobra has a crap ton of bass regardless of volume. Basically the same speaker position as the F body too, with the exception of the rear package tray speakers.

 

I've got the same issue in regards to the speaker mounting and door panels; My personally suggestion and something I know makes a difference... see if you can get a set of door panels from a Monsoon car; those have the built in pods that angle the front drivers more up towards the driver/passenger heads and improve the sound imaging a lot.

 

The Mach 460 system is a completely different animal. It has four 6x8 woofers and four mid/tweeters driven by three separate amps. One 60W RMS amp powers all four mid/tweeters. Two 85W RMS mono amps power the four woofers (one amp for each side).

Not at all similar to the Monsoon system with its single amp and only two sail panel 6.5" woofers.

 

...so... basically the Mach 460 sounds better with more bass from more cones of larger size with more power??

 

I think that's only really applicable to Firebirds/Trans Ams, I'm pretty sure all Camaros have the same door panels, at least when it comes to speaker mounting.

I'm sure that system has a higher theoretical ceiling than a factory Monsoon system, but you're still ignoring the fact that I have what I feel to be plenty adequate bass with my upgraded speakers in other listening positions in the car. I thought I've been pretty clear that I'm not trying to blow my doors off, I just want the bass that I know is already there to be as apparent from the driving position as it is from other weird spots in the cabin. I understand when it comes to these cars, everyone wants to go the "more power" route all the time, but does literally everything have to be brute-forced with them? Can we not do anything with finesse over raw power?

 

I suppose, but I believe this to be a rare case where a "finesse" solution with phasing DSP effects or custom enclosures is not as cost effective as brute force.

Finesse to me means using speakers with high sensitivity, and FD amps with high effieciency and low heat. Not some BS Bose Store listening room with tiny Accoustimast speakers positioned perfectly in a dimensionally perfect room with no open walls, that will never sound as good when you get them home.

You posed a problem, asked for ideas/solutions, and I tried to offer one. I tried to make a case for it, but if it doesn't meet your needs or won't leave you with a result you'll be happy with, I'll be curious to see what else comes up. Can we at least agree that "brute force" would probably work?

 

Indeed. I apologize too if I come off as pushy or rude, I really don't mean to. I'm a tinkerer at my core, so I always have the itch to try things kind of outside the box to adress problems that I find.

I'll be sure to follow up in this thread with the different routes I take and if they are successful or not. I have a lot of confidence in what this setup should be able to do, so if I can find a cheap (while still effective and reliable) way to make the best out of it, I want to share my findings.

Probably won't have time to open the doors up until the weekend though, unfortunately.

 

Oh crap, sorry.

If that is the case, then I'd just make a set of custom door pods to angle the driver/tweeter similar to the monsoon system. This will allow both proper aiming, and making a sealed enclosure to help the speaker perform a little better.

 

Aiming the speakers a bit higher could actually be a good idea for the camaro.
Did you end up trying custom pods?

I already have a 10" sub and sound deadning for the doors. That said, I would definitely build an mdf custom pod if it helps imaging and accurate midbass performance. Can anyone else comment on this mod?

Cheers!

 

if you do a custom door pod you want little to no MDF in it, MDF will absorb the moisture in the door when it rains and grow some nasty black mold very quickly, my buddies 96 had a leak in the back window seal and water got in and half that box was BLACK, had to just toss it and we never made a new one.

 

Really? I've used MDF for them a ton; just have to make sure they're fully encapsulated in Fiberglass resin. MDF for the frame, supports, and mounting ring, then an old/cheap fleece blanket for the main contoured surface.

 

that's the one scenario where it is ok, because it is encapsulated and thereby waterproofed but don't just slap raw mdf up there.