Should I Try A DIY 12 or 15" Sealed Design??

[Fore]

Hello all,

Very informative forum firstoff. I recently seriously upgraded my 2 ch. system finally upgrading from these bass generous Von Schwiekert VR4 II's to a German made Tidal Audio 'Piano's
http://www.tidal-audio.de/english/startenglishprodukte.htm
Some nice new silver wire, and an upgrade in amps to Canary 339 (50wt/ch 300B).
This is also my HT setup that I run thru a seperate system, same speakers. My room is in a bungalow house, 13'x11x8', but its open floorplan, and is connected to another room of the same size, and one open doorway on the backwall. Long story short, small room, but open so bass needs to accomodate this. I've had a Sunfire sub for a long time, and have been disappointed a long time too I want a new sub/subs that'll integrate seamlessly and give me organ producing bass (and by then, I'll be happy with the bass for HT). But room is very tight.

Anyway, I've been saving, and would love to buy 2 JLAudio F113 stereo subs. But I don't think I could fit them in one, and, I haven't saved that much money yet. So I've been wondering to try a diy sub. I'm handy with wood and have the tools too. But I downloaded WinISD and played with 3 drivers: TC Sounds TC3000 15", tc2000 15" and a Creative Sounds CSS SDX15 in a sealed box. I haven't tried the 12"s yet....but to be honest, a lot of it's above me and I"m having a hard time understanding it all. I've tried boxnotes too but only coming up with box sizes and int. vol. estimates. But I know see why buying a buying a 'plug and play' sub like the Fathom. I'm no acoustic expert and I'm beginning to think I shouldn't do it.

I picked these based upon alot of positive net reviews. My budget is say $3-500 per driver. (I've read it's more important to fit the right sub/subs in over a particular driver though. Also, thinking of something like a Behringer EP2500 per driver and some Behringer BFD or 24/96, and a mike. It'd be nice to have two inputs: One rca input from my Lexicon, and one speaker level for 2ch music?

Lastly, just to discuss box size. I can only have 13" deep if I wanted stereo subs that'd fit next to my mains. This really limits this option, my desired option to be honest. I could squeeze maybe a 18" cube behind the mains. Or I could just do one sub that'll fit between the couch and wall...like 18"W and whatever D and H.

Sorry for the length, but I realize the better you understood my desires and limitations, the better advice I'll get. Thanks for any suggestions.

Fore

 

[Fore]

Did I ask too much? Seriously, I hope not. Any suggestions guys?

 

[noodle_snacks]

You have one question mark in your post, and it doesn't constitute a question. It sounds like you want help picking a design and drivers. You need to set some specific goals, budget, low frequency extension, displacement, distortion, aesthetics etc. Then from those goals determine your best options.

Open floor plans are good in terms of room modes generally, however it does also raise the requirements for displacement. In my view a single 12"/15" driver would probably not be enough for your application (depends on spl requirements). Depending on your aesthetic goals, lots of large 15in subwoofers mightn't be good. You also have to remember that going sealed essentially shoots yourself in the foot in terms of spl at low frequencies.

Have you considered an IB?

 

[planet10]

Witgh your driver budget, 2 x CSS SD12 per side would be my choice (i have both SD12 & SDX15 sitting here now). I just did up a sealed push-push design for the SD12 and we will likely be going ahead and building them for a customer.

The shape almost satisfies your 13" criteria (they are 14" wide -- but i'd use them turned 90 degrees so that becomes 14" deep).

Mail me if you'd like to see the plans.

dave

 

[Fore]

You have one question mark in your post, and it doesn't constitute a question. It sounds like you want help picking a design and drivers. You need to set some specific goals, budget, low frequency extension, displacement, distortion, aesthetics etc. Then from those goals determine your best options.

Open floor plans are good in terms of room modes generally, however it does also raise the requirements for displacement. In my view a single 12"/15" driver would probably not be enough for your application (depends on spl requirements). Depending on your aesthetic goals, lots of large 15in subwoofers mightn't be good. You also have to remember that going sealed essentially shoots yourself in the foot in terms of spl at low frequencies.

Have you considered an IB?

HI Noodle_snacks. I guess I should've been more specific in my questions as you noted. Sorry. And yes, I'd love to have some ideas thrown out. To answer your questions: My goal is a sub that disappears accoustically, and gives me...I was hoping >20hz?...like 18hz? Something that'll be nice and clean say with mens deep vocals, and slammin' enough to make kickdrums sound real/realish. I don't want higher distortion for higher spls.
That;s what worried me about TC Sounds drivers, higher distortion comp. to others. Aesthetics are important too, but that's mainly a box making problem. And I'm afraid you maybe right too about single driver sealed box not being enough due to my open floorplan. I don't have room for a IB design. And keeping it sealed, at the expense of spls, allows more flexiible placement and in my experience, is tighter than a ported design.

Witgh your driver budget, 2 x CSS SD12 per side would be my choice (i have both SD12 & SDX15 sitting here now). I just did up a sealed push-push design for the SD12 and we will likely be going ahead and building them for a customer.

The shape almost satisfies your 13" criteria (they are 14" wide -- but i'd use them turned 90 degrees so that becomes 14" deep).

Mail me if you'd like to see the plans.

dave

Hi Dave, great to have you here! I've seen several of your designs and boxes. Very nice work.

So why do you suggest going with 12"s over 15"s? What's more 'ideal' cause it sounds like you're recommending the 12" do to room constraint for stereo subs...not that I may disagree, just what your thoughts were in suggesting a 12" design?
And the CSS SD12's over TC Sounds, or Precision sounds? So many drivers out there that again, I"m wondering why to this brand?

But a 14" box would work pretty well. How'd your built version turn out? Are you happy with the sound? Using a Behringer I assume? Amp? Any graph to see the output freq. response?

Thanks Dave.

 

[chops]

You also have to remember that going sealed essentially shoots yourself in the foot in terms of spl at low frequencies.

That's an absurd statement.

I don't know what sealed subs you've been listening to lately, but my 6.3cf SEALED push-pull 15's provide more than enough SPL straight down to about 14Hz, and enough oomph to pressurize the entire room down to 10Hz. And that's not even pushing it to its limits, either.

Just as a side note, I once measured a max SPL (via my SPL meter and TrueRTA) of 100dB @ 16Hz at my listening position, and it was loud as heck and still not pushing it to the limit.

 

[planet10]

Originally posted by Fore So why do you suggest going with 12"s over 15"s? What's more 'ideal' cause it sounds like you're recommending the 12" do to room constraint for stereo subs...not that I may disagree, just what your thoughts were in suggesting a 12" design?
And the CSS SD12's over TC Sounds, or Precision sounds? So many drivers out there that again, I"m wondering why to this brand?

I won't build a serious sub unless it is push-push (and stereo is a good idea). So 2 12s instead of 1 15, 2 15s instead of 1 18, Also you would be challenged to hit your size target with push-push 15s. All other things being equal a 12 will also reach higher than a 15. Something that is good when you consider getting a smooth hand off to the mains (of course, how high you take the sub is a factor)

CSS because i have them here to play with. ie familiarity.Keep in mind that CSS drivers are the spiritual descendant of the Adire drivers.

dave

 

[noodle_snacks]

That's an absurd statement.

I don't know what sealed subs you've been listening to lately, but my 6.3cf SEALED push-pull 15's provide more than enough SPL straight down to about 14Hz, and enough oomph to pressurize the entire room down to 10Hz. And that's not even pushing it to its limits, either.

Just as a side note, I once measured a max SPL (via my SPL meter and TrueRTA) of 100dB @ 16Hz at my listening position, and it was loud as heck and still not pushing it to the limit.

It seems you are having trouble understanding my statement, it was perfectly factual. I was refering to the fact that you need a considerable low frequency boost to get flat response down that low. It also depends on what you consider loud, I don't personally consider 100db that impressive.

 

[chops]

It seems you are having trouble understanding my statement, it was perfectly factual. I was refering to the fact that you need a considerable low frequency boost to get flat response down that low. It also depends on what you consider loud, I don't personally consider 100db that impressive.

No, I didn't have any trouble at all understanding your statement. It is NOT true that you "need" considerable low freq boost to get a flat response. I know, I have the proof sitting in the next room.

100dB @ 16Hz isn't too shabby, not to mention that I still have plenty of power, power handling and Xmax to go louder. Also, I use ZERO equalization on my sub and it's perfectly flat from 80Hz down to 16-18Hz, including room gain.

And personally, I don't really care what impresses you.

 

[Fore]

Thanks Dave. My mains specs say they go down to 30hz, so I was thinking of crossing over at about 50hz. Do you still think 12's are the way to go then?

 

[AJinFLA]

A pair of Rythmik DS12 subs would meet your budget.
Don't let the low price fool you. These are excellent SQ/music subs, with a healthy amount of output given the size. Extension well below 20hz without additional eq.
A search of this forum (and others) should give you some additional info from others who have built them. Best of luck.

cheers,

AJ

 

[noodle_snacks]

I am not going to argue about nonsense.

Generally kick drums have a fundemental of around 50hz. The lowest string on a four string bass is about 41hz (5-6 string basses can get lower if relevent to your musical tastes). In short, the low frequency requirements for music are often not huge. Often sealed subs will handle practically any music thrown at them (but as always there are exceptions, which you should identify). Use spectrum analysis software to determine the extension of the music you listen to, rather than relying on anecdotal evidence. The extension requirements for home theater are definately somewhat lower, but energy below 30hz isn't extremely common.

I would agree with dave that 2x12in speakers are better than a single 15in. Both because push-pull type setups are possible (and are a good idea), and because you can more optimally position things for the most even excitation of room modes. In your original post you did ask about the use of equalisation. I actually have BFD as part of my own setup, and have set them up for a number of rooms. Optimal placement of subwoofers is very important so that the deviation of frequency response between seating positions is minimized. If attention is not played to placement, then the bfd will only really do any good at one seating position. If you go down that route don't forget to factor in the cost of a microphone and preamp (though its possible with a SPL meter).

One other point worth considering, often 12 and 15in drivers are based upon the same motor. The additional efficiency 15in drivers offers if the cost difference is not great is often worth it in my view.

 

[Fore]

I'll check Rythmic subs for sure AJ, Thanks.

And also Thanks Noodle for that perspective as I've never actually sat down and done measurements. I don't have any measuring equip. other than my old RS meter and a new laptop with a basic soundcard I'm sure. (Do you think your BFD is as good as the Velodyne SMS1? I've never used any of these and am just curious)

I'd love to use 15", but it'd be almost impossible to place stereo subs. Either way, they are going to have to be a near cubed design to fit next to the mains.


Is there an affordable but good box with crossovers, phase control and maybe that Linkwitz circuit for low end bass boost? Just curious as to what's available premade.

Very interesting stuff!

 

[AJinFLA]

If you don't have space for 2 12's, the Rythmik is available as a single 15" DS15 . The drivers are customized TCsounds (with a sensing coil for the servo feedback system).

cheers,

AJ

 

[chops]

I am not going to argue about nonsense.

Yeah, nonsense... That's it.

Eventhough Rythmic basically claims the same thing with their sealed subs, and AJinFLA mentions "Extension well below 20hz without additional eq", I'm assuming WRT Rythmic's sealed subs. Neither of which take into account room gain, which can help even more.

And for the record WRT this thread, if properly designed in the right enclosure with the right driver(s) and positioned in the right spot in the room, one does not need a Linkwitz Transform circuit in order to reach well into the lower section of the lowest octave, regardless of what some may "think".

 

[noodle_snacks]

I'd not encourage you to take chops advice, or even my own, spend a small amount on measuring gear and discover the truth for yourself (as opposed to believing marketing dribble).

I looked at that velodyne thing, its a parametric eq like the BFD is, advantage being that one might be able to have it set automatically (but with that you probably loose control). You'd have more control of your results with a bfd, and costs may well be better (not sure)

 

[chops]

I'd not encourage you to take chops advice, or even my own, (as opposed to believing marketing dribble).

Whatever. I guess you know my stereo system better than I do. That's pretty good considering you're clear across the world from me.

Oh well...

 

[MJL21193]

You also have to remember that going sealed essentially shoots yourself in the foot in terms of spl at low frequencies.

I'm with you my droogie. Time for a little of the old in-out or was that push-pull?

 

[noodle_snacks]

Eventhough Rythmic basically claims the same thing with their sealed subs, and AJinFLA mentions "Extension well below 20hz without additional eq", I'm assuming WRT Rythmic's sealed subs. Neither of which take into account room gain, which can help even more.

The rythmic subs do get that low without additional eq. Notice the word additional. I believe low frequency response is boosted as a result of the servo...

 

[chops]

I'm only going by the various sealed subs that I've built over the years, and they have all displayed similar extention in my room without any equalization. The only one that didn't was a 9cf sealed sub I built with a Klipsch 18" Pro driver (which I'm told was most likely an Eminence). That one had strong output down to about 30Hz or so then sloped off after that, with very little if any output at or below 20Hz. It was tight and punchy as heck though.

The twin, dual 15" dipole subs that I built a while back also extended down to about 16-18Hz, then dropped like a rock afterwards. Still, these were the best sounding subs I have ever heard, but just was too large for my room.

The only non-DIY sub I ever had was an SVS PB12-ISD/2. While it had great extention and had usable output down near 12-14Hz, it was too mushy and exaggerated for music reproduction no matter what settings I had it on, hence why I got ride of it about 6 months after I bought it.

So you see, I have good reason to dispute the notion of "needing EQ" and/or "shooting yourself in the foot going sealed", because in my experience in my room, it just hasn't been the case at all.



Now I can understand the need for EQ or a LT for subs that use small enclosures with large drivers like Bag End and Velodyne or small enclosures with small drivers like most everything else out there these days. The small enclosures reduce bass output by a large margin, so you need a huge amount of Xmax, huge amounts of power and huge amounts of EQ to get anything worthy out of them.

Again, I have never built any of my subs that way, so I never had the need for EQ. In fact, that's one of the things that attracted me to SVS subs, because they design all of their subs with large enclosures for proper bass extention. Unfortunately, I just don't care for the sound of them with music. Even my brother's little SVS PB10-NSD has a large enclosure and great bass extention below 20Hz, but it's still too mushy and exaggerated for music to me.

Maybe this will clear things up a bit about where I'm coming from.