I think I already know the answer. Would it muffle the sound of a 10in subwoofer in a regular cab truck to put it behind an interior panel? Or would it not be noticeable?
I think I already know the answer. Would it muffle the sound of a 10in subwoofer in a regular cab truck to put it behind an interior panel? Or would it not be noticeable?
Subs are often hidden in odd places in OEM vehicles (Tesla even puts one in the corner of the trunk!) and professional audio setups, that's what I know.
I can't imagine it would muffle too much. My regular cab S10 had a 10 in a truck box behind the seat, the woofer bounced off the seat, and it still sounded fine and loud. Did have trouble keeping the rear view mirror on though.
Depends on the panel and if it is more open to the outside of the cab behind the panel. Bass is omnidirectional, so as long as it's still in the airspace of the cab, you're not likely to affect the output of the sub. It's more likely to be a challenge to keep the panel from rattling...
Im essentially building a false wall for the rear cab wall of the el Camino. Something made out of hardboard, closed cell volara foam, and vynil. Just for cosmetics. It would be much easier and cleaner in appearance to make one solid panel than making a perfectly located hole for the cone of the sub to protrude through.
Rattling will be a challenge, i agree. However, that should be easy enough to solve. The other side of the sub and box is attached directly to the sheetmetal of the cab. But that is water tight. So i would think it would be more open to the airspace of the interior than exterior.
The stereo system sounds fantastic. I just dont want to screw it up while finishing the interior.
One perfectly located hole for the cone may not be that easy, but if you want to be sure you don't impact the effectiveness of the sub, you can cut a couple small raggedy holes and disguise them with speaker grilles.
Like mentioned, subs are non-directional, so location and direction aren't that important. Most are mounted remotely in a trunk anyway.
The sub box in my Tundra was mounted under the rear bench, so pretty muffled compared to just a panel and it sounded great.
Y'all have pretty much confimed my self answer of " both good. Quit overthinking it"
My $0.02:
Oooh. Hadn't thought about that. Accurate hole it is. Cant loose too much space back there.
Lower frequencies tend to pass through objects much easier. Its the same reason your microwave has a perforated barrier between you and the radiation. Most of the radiation (with its very short waves) can't pass through the holes because of its frequency. It blocks high frequency waves.
But with low frequencies, they not only pass through, but are sometimes amplified by barriers (when the barrier moves sympathetically with the sound waves). That's why you always hear the sub pounding in a car driving by, but can't hear any of the treble.
Long story short, don't worry about barriers with your sub. DO worry about distance to your ears. If you put the sub too close (within the distance of one full sound wave) it will attenuate what your ear hears. The wavelength of a 50hz tone is almost 6 ft long. Putting the sub closer than 6 feet away from your ear means that you're inside the sonic range of that wavelength and you won't hear it as loud. The closer you get to a driver, the higher the frequency will be for that attenuation.
The good news is that when the sound wave hits the far side of the cabin, whatever doesn't pass through will be reflected back, giving you another cab width of length for that wave to form. This is why most trunk and hatchback installations have the subs pointing backward; to give the sound wave more distance to form before it gets to your ear.
I think the biggest trade off to putting it where you want is that it will not play nicely with the treble. During louder bass moments, the treble might attenuate at the same freqency as the bass. It will sound like the treble will cut out 50 times per second. That is also why many truck installations have the subs behind the seat pointed forward. When sound waves fight each other in the same direction, the bass usually wins disrupting the smaller treble air mass. Think of it like waves on the beach. If a small wave is coming in and a big one overtakes it, the small one gets obliterated. If the big wave comes from the side, the two just meet at an angle and continue about their business.
Ill add some pictures of the current setup later. I think im understanding you correctly curts, but want to make sure. I dont think theres any cancelling effect going on, but will wait until pictures to have the professional opinion chime in.
Thanks yall.
elemental designs shallow mount 10 in sealed box, centered between the seats and bolted to the back cab wall.
20171102_183541 by Michael Crawford, on Flickr
20171102_183547 by Michael Crawford, on Flickr
front 4x6 infinty reference speakers in factory cowl vent holes, with XTC foam baffles behind them. tweeters angled towards drivers seat to the best of my ability
20171102_183556 by Michael Crawford, on Flickr
im still debating putting my spare alpine 6.5 components or kenwood 3 ways in the rear for rear fill. dont thing i need them, but midrange on this is definitely not where id like it to be yet.
the rear cab wall in question would start at the shelf under the rear window and extend the whole way to the carpeted floor, wall to wall. be made just like my door panels, same method of volara foam, hardboard, and vinyl. it would cover the whole rear wall, hiding the insulation, amp, speaker box, provide a good spot for my jump terminals, and some additional sound deadening. i could make it flush with the package tray shelf, which would provide about an inch worth of clearance to the sub cone, or let the sub cone and surround be visable through, probably protecting the cone with some sort of grille.
does this help you guys? also, the side picture begind the seats really does not do justice to just how little space is back there. and my briefcase and donut spare still have to fit in there as well. would be nice to put a duffell bag back there when travelling, too.
If you can make kick panels for your front speakers, that will help mid bass a lot. Are they amplified, or just off head unit power?
Im picking up factory kick panels Saturday. The speakers are in a sealed foam baffle already, but now that im thinking about it, may be undersized and starving the driver for air.
Theyhave 50 watts rms through 12 gauge wire run to them. They can go stupid loud.
The midrange im thinking about is more like the vocals on Marilyn Mansontracks. Trevle from cymbals and guitar are crystal clear, bass is right where i want it, but vocals are muddled and not well balanced to the rest. I have not run through all the eq and amp tuning with the new front speakers and head unit yet. So there may be significant ground to be gained there.
In reply to Dusterbd13 :
The factory kick panel cover may make a marginal improvement, but what I was intending to say was a full kick panel enclosure, like Q-logic custom enclosures on a GRM level. Just a sturdy wood board to mount the speaker to will improve the frequency response in just the range you are talking about. The foam baffles are not truly baffles and more speaker protection. You are not truly separating the front and rear waveforms with a flexible foam bucket...
Ah. Gotcha. A sheet pf hardboard or aluminium is in tje plans for finishing blocking the cowlvent s. Will do them prior to any other changes.
Thanks for the pics. I like where you put it. Its as far away as it can get in a truck cab, so good choice.
Now about that particle board.... 
Also agreed on good baffles for the fronts. You want the frames to stay put so the drivers can do their work. Much like you want a stiff chassis so the suspension can do its work without additional compliance from the car.
The osb was what i had. Sounds good though. Would mdf make a noticeable difference?
Its the same reason to keep the high-frequency speakers planted. If the baskets and magnets can move, the cone isn't doing its job. But with subs it is even more important for two reasons: 1, you have an exponentially higher mass of air being moved, and 2, the enclosure itself is part of that baffle since it is trapping the pressure waves and suspending the cone. If the box can flex, the sub is losing that much SPL.
In smaller enclosures where the passband (the frequency range in which you're operating the driver) is higher than the resonant frequency of the panels of the enclosure, its pretty moot. Take for instance a bookshelf speaker. They might make frequencies in the 50 hz range, but they're not high SPL. Since the individual panels of the enclosure are so small, the chances of the panels resonating is very slim. A 6" piece of plywood won't have a resonant frequency of 50 hz, it will be more like 3000 hz, so the chances that you'll make enough SPL to cause the small panel to sympathetically vibrate are pretty slim. In those cases, anything rigid will suffice. Smaller full range enclosures I tend to use 5/8" or 1/2" Birch ply because its easy to use. I sometimes use MDF on small enclosures, but its overkill and not quite as durable to abrasions and impacts. (not good for me since most of my stuff is theater and live performance which means a lot of abuse).
On larger enclosures where the resonant frequency of the panels is within the passband, I like to use MDF. This is true for many sub enclosures with large panels. There is an almost certain chance that (if given the opportunity) the panels WILL flex with the pressure waves. In these situations, MDF is almost always needed. Not only is it very rigid, it is acoustically dead (or close to it). The non-homogenous mixture of things in the material means that it doesn't "sing." It doesn't have a single frequency peak that it sympathetically tunes with. Have you ever tapped a 2x4 on the floor and it makes a tone... like you could go to a piano and find that it makes an F# when you hit it. Then you take a longer 2x4 and find that it makes a B when you hit it. Plywood does the same thing, but to a lesser extent. MDF doesn't really have that. It just makes a thud. That's what you want. You want enough rigidity to adequately contain the pressure without deflection, and also no resonant frequency.
Try a fun experiment. Cut two identical pieces of MDF and Plywood. Put them on a table and then put a palm sander on the table. Adjust the speed of the sander up and down. You'll find one certain speed of the sander that the plywood will dance or make noise. The MDF won't.
So, in reality, you are making bass, but set a coffee cup on that box during a big bass note. I promise you'll be cleaning up coffee. Build it out of MDF and you may clean up a couple drops, but not the whole cup.
The other concern I have with OSB is that as it flexes, it degrades rapidly. Its a bunch of chips glued together, and every time it flexes it breaks some of the glue bonds.
Long story short: I suggest using MDF. Nothing wrong with using what you have (this is GRM after all) but I think you'll notice MUCH better performance with 3/4" MDF. Use your OSB as a pattern. I like to assemble mine with good wood glue and use corner blocks to increase the glue surface area. I also cheat and use screws. The "right" way to do it is to just glue and clamp, but that gets time consuming... glue three together and wait a day, then two more and wait a day, then the last one and wait a day. Screws in endgrain of MDF don't do much for assembly strength, but they work brilliantly as clamps. Glue it, screw it, call it a day.
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