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Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plus st

2K views 14 replies 4 participants last post by  Thegenuinearticle 
#1 ·
Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plus st

I wanted something different that was going to be super strong but relatively light weight and with a semi-natural look...1.5 cubic feet which for the discovery should yield an F3 of around 38 HZ. Will be powering with an Audio Control Lcz1.800...Baffle is 1.5 inches thick roughly in a section due to the recessed flush look I was going for...Enjoy the build pics
 
#3 ·
1/4 straight bit with multiple passes. The Jasper circle jig is designed to account for the Kerf of that diameter bit. The multiple passes is sometimes a pain but it's just always how I've done it. Maybe one day I will use a 3/4 and just use lower diameter marks to offset the difference..
 
#4 ·
Re: Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plu

That is a very nice box build. Great sub too. How would you describe he performance of this sub compared to others? I ran a Scanspeak Discovery 12" in a 1 cu ft box for a while. Sounded absolutely fantastic but lacked in output. I just recently added another in a new box each with their own 1 cu ft chamber. Much more sub presence now. I never tried it in a 1.5 cu ft box. I have run many subs over the years and this one is the most musical of them all.
 
#5 ·
Hey thanks for viewing my post and appreciate the comments. Well I haven't used the sub yet, but I do have other experience with subs comparable to it. I actually at the moment use two SEAS Lotus Sw300 12 inch subs in my home setup in custom sealed enclosures at 2.85 cubic feet each...Yeah I know right pretty huge, but when I plot the parameters in modeling software in order to get a .707 QTC the woofers actually call for 3.5 cubic feet each. Well I simply am not going to build a 3.5 cubic foot sealed enclosure for a 12 inch sub so Just like in car audio I struck a compromise. In the past I ran these two subs in 1.00 cubic feet enclosures in my car and even though the subs were very musical they just tended to be choked and the extension down low was lacking. Well it's the same thing with these Scanspeak subs as well. If I'm not mistaken when I modeled the discovery sub it called for around 1.7 cubic feet for optimum QTC of .707 and I think the F3 was around 37 HZ. The thing is with car audio the manufacturers will rely on cabin gain to compensate for smaller less than optimum enclosure sizes with QTC's sometimes at 1.00. Yeah the driver can handle more power in those smaller sealed enclosures but again the subs tend to be choked and the really nice extension down low is traded off for cabin gain which in a car is still really exciting for most people with frequencies around 40 HZ but to reach down into the low 30's and below these subs will need more airspace....
 
#6 ·
Re: Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plu

I got my subs from Madisound. They must have taken into account cabin gain because they list 1 cu ft per sub for car audio. This must be also why I am able to give them a lot more power than the listed RMS. Thanks for all that information. I have a very small hatchback so 2 cu ft is all I'm comfortable with. I do get a lot of cabin gain with it being a hatchback.
 
#7 ·
Re: Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plu

Those carper covered boxes are probably as good, but they alway look a bit ordinary.

That distressed look, catches my eye. It is tasteful.
 
#8 ·
Re: Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plu

What 12 inch SQ subwoofer with similar mounting depth will get to low 30 Hz in a sealed enclosure with volume around 1.5 cubic feet? ? ? What performs better than the Scan-Speak?
 
#9 ·
That's a good question. There are a number of things that can be touched on with what seems to be pretty difficult in finding a 12 inch sub that can do this. It seems most of the current dedicated car subs are following this trend where all of the more "higher quality" models of a manufacturer's lines have that super huge surround, a really thick/stiff cone, and a large magnet assembly. The problem with these subs is that those huge surrounds and thick cones typically raise the resonant frequency of the sub and the efficiency of the sub is also compromised. Those subs typically end up with efficiency numbers like 83 DB and people then brag about the power handling and I just shake my head because now instead of being able to throw 300-500 watts at a subwoofer for respectable output you have to send more like 1000 watts to the less efficient subwoofer in order to make up for its lower sensitivity.

Honestly I could be wrong but I dont think you are going to find a subwoofer in the mobile realm that is going to have a low resonant frequency like the discovery (17 hz) , with an 89 dB efficiency, and with such a shallow mounting depth. If I'm not mistaken even Scanspeaks revelator line doesnt have a sub with a resonant frequency as low as the 30 discovery. If it's going to be found it's more than likely going to be in the home side of drivers which is really more of what the discovery is in a sense.

One other sub maybe worth looking at is the SEAS LROY 4 ohm 10 inch. It doesnt have quite the same shallow mounting depth but it has a low resonant frequency along with decent sensitivity ratings. It looks to be built like a tank as well and has a very good amount of xmax. You could probably throw 500-800 watts at this subwoofer in a 1.5 box with no problems. I have not modeled its parameters yet but I'm interested in what kind of volume it needs for a .707 QTC and what the F3 will be...
 
#10 ·
Re: Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plu

I looked at the Morel subwoofers and the JL Audio TW5 (thin woofer) that is 13 inches in diameter and when I modeled enclosures I did not find something that was able to play significantly lower than the Scan-Speak 12”.

Open to any outside input and ideas...

Beautiful enclosure- to the original poster.
 
#11 ·
Caudio, yeah it's pretty difficult to have a single 12 in moderate sized enclosure really dig deep into those high 20hz areas and below without being ported. To do it sealed with the discovery you would probably need two 12's and each in 1.5 + cubic feet. One can always go ported but once again compromises are made going ported and we have to give up trunk space with a larger enclosure and add more weight in the process. My goal with this build was to strike a balance of getting the most low extension with trying to keep the weight( hence the plywood for the enclosure and amp rack ) and space down to as reasonably low as I could. My Si sedan has around 200 hp at 2900 lbs and although it's not that fast of a car, I still wanted to try and keep it relatively lean. I've had systems before that definitely bogged a car down and even some where the rear of the car would slouch due to all the MDF, extra battery, and crazy inefficient old school heavy class AB amps...Dont really want to go that way again...

Honestly if you are just absolutely craving the frequencies below 30 hz the discovery wouldn't be a bad sub to go ported with either. You could probably get well into the 20's with it at 2.0 cubic feet(which isn't an insanely huge enclosure). Heck I may also build another ported box for mine just for ****s and giggles around that size with a tuning in that neighborhood just to plop in the car to see how I like it...
 
#12 ·
Re: Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plu



I know for the Seas that they make a passive to match it, and I am 90% sure ScanSpeak also does.
 
#14 ·
Re: Scanspeak discovery 12" plywood enclosure build with bracing and more bracing plu



In home theatre they like to go low (~20ish Hz), but there are not many pipe organ songs in popular music...

Most of time it is the extra volume of a ported box, and the port itself... That makes going sealed a more viable option.

Then going to a smaller aero port gives some volume savings, but they seem to chuff a bit more than a PR does.

The fact that Seas and SS makes ones specifically for their subs indicates that they are designed to work.

That distressed box is tasty.
 
#15 · (Edited)
Ha ha...What exactly is distressed? I like the sound of it but I'm just wondering how that description fits to the look of the enclosure? Maybe not quite the description of the look I was going for but will run with it...Went with simple rubber feet and a $1.35 terminal cup...Hey some things just dont have to be expensive. If you like the enclosure check out my A pillar build pics...DiyMobileAudio.com Car Stereo Forum
 
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