I have a 1250-watt plate amp, want to build sub! (1 Viewer)

[Brian Bunge]

I honestly don't know if it would outgun the deftech or not. But DefTech is not known for high performance subs. I'd bet that a Shiva in a ported enclosure, like the Dharman, would probably be good competition to the super cube. The fact is, with 1KW+ power you need a driver with high excursion/power handling. That excludes any driver I'm aware of in the $100 range. You're probably looking at $300-$500 for a driver with that kind of power handling.

Here's what a customer of mine had to say about a dual Tumult setup that I built for him:

"Wow. Sound is great....While it is impossible to do an A/B, the tumults easily sound as good as the dual Aerial SW12 and Revel B15 that I have listened to-quite possibly
better. I have never heard a dual HGS-18 system, but this is clearly better than any single HGS 18 system that I have listened to."

 

[Vince Bray]

The best solution will be stereo mid subs, so probably a 10" on each side

Is it a stereo plate amp?

A tumult could be designed to be happy up to 80-100hz. You need a design that stays well behaved, but I don't think that's asking too much. All the crossovers between the lows/mid-lows/maggies increase the issues with integration. Again, I would do a tumult, sell the deftech. You'd come in much cheaper (a couple of grand or so) than the velo trade-up. This is MHO, but then, you asked

Of course, the velo is spec'd 14hz to 120hz +/- 3db, that may well fix your problem by itself.

 

[Robert Cowan]

i understand about the powerhandling, thats why i was entertaining multiple drivers. unless you have experience with the supercube reference, its difficult to judge its performance.

plus, you are comparing to the HGS18. the DD-18 is much different. its quite unique. also, the main reason for not replacing the deftech or velodyne, is that i am going to get the velodyne for future value. its an investment. no matter how good a dual tumult would be, the velodyne DD-18 would have MUCH greater resell value. then, down the road, i could sell it and get a LOT more in the long run.

so, this is why i really only want to spend $200 on the project. if i cant build anything respectable, the amp will go up for sale... but i think for $200 i could make something usable.

 

[Robert Cowan]

just to clarify, the velodyne will be free... so its not like im dropping $5K for it. if i had to spend that, i would build me a few tumults!

 

[Brian Bunge]

so, this is why i really only want to spend $200 on the project. if i cant build anything respectable, the amp will go up for sale... but i think for $200 i could make something usable.

And I'm telling you that you're basically throwing away $200. If you're comfortable with that then by all means, plow ahead.

 

[Robert Cowan]

well, i appreciate the advice, not so much the tone or its conveyance, but i do appreciate it.

i guess i will have to rethink this whole thing. im not willing to build the "end all" sub right now. since we are talking $1K+ in drivers, im not really ready to do that. i will look at the velodyne as an investment.

i would truly like to hear a sub like the ones you are talking about. ive only heard poor budget built subwoofers, and they sound just like that. i have yet to be truly impressed by a DIY sub.

if you, or anyone else, has something like this and is in the denver area, i would be very interested to hear it!

 

[Brian Bunge]

Robert,

I apologize if my tone seems harsh, but I truly am trying to help you understand exactly what you can/could have if you're willing to make the leap of faith. Granted it's a BIG leap. Most people have a hard time wrapping their minds around the notion that a DIY sub could possibly outgun/outclass even the most expensive high end subs. Case in point, the Krell MRS sub (about $25K I believe?) could be blown away for well under $5K.

ThomasW is in the Denver area I believe. I don't mean to speak on Thomas' behalf and I'm not sure what all he has lying around the house, but he should be able to show you what can truly be done with the right setup. He's built some serious subs and should be able to make a believer out of you.

 

[Robert Cowan]

apology accepted.

like i said in the VERY beginning, i am not a beginner to DIY, but i am to speaker DIY. i understand the markup of audio (i work in retail high-end audio). and i understand that a sub can have the same absurd markup that anything else could.

but, since i work in the industry, i upgrade ONLY by buying stuff (or getting it free on programs), and selling it later, and repeating the cycle. the deftech was gotten this way (from $20 initially). and when i get the velodyne, my next upgrade could be just about anything i wanted... i do this for all my stuff. at that point, if im bored with the velodyne (i will be, i always have the upgrade bug), then i will certainly look into building an awesome sub. i will have the funds.

it just seems to me that it has to be a little more complicated than getting a couple (or more) good drivers, a parametric EQ, a good amp, and an elcosure. i guess thats all there is to retail subs, but im always skeptical when someone says they can build something that costs $5K retail for only $500.

ive already emailed thomas, and hopefully he can show me something amazing! so i guess coming back to my original question, what should i do with this amp? sell it, save it, or use it for something silly? i can pick up an infinity kappa perfect 10.1 for $70. that seems like it could handle the power (if used moderately). im not saying it would be great, but would be a damn impressive sub for only $100.

 

[Brian Bunge]

Thomas used to own a high end salon so he should have the experience to set the record straight.

Me personally, unless I knew exactly what the specs were of the amp, I'd sell it. Without knowing if it's got the servo, limiter, and any kind of boost built-in you'd be shooting in the dark.

Assuming you can get full T/S parameters for the Kappa and design and build an appropriate box for it I think it could be decent.

 

[Robert Cowan]

hum, maybe i will just sell it. someone out there must want one. im sure i could get a few bucks for it. well, thanks! i'll let you know if i hear anything i like. and if i do ever build a sub, ill let you know, and call on your knowledge. if i were going to do it, i would do stereo dual tumults. it would be within my price range, and why not?

 

[Brian Bunge]

The customer I quoted is using his Tumults with a full Aerial Acoustics setup so I imagine they could be quite satisfying for you.

Have you seen any of Thomas' subs? The Aerial Stryke sub should be quite interesting as should the 12 Shivas Dancing.

 

[Robert Cowan]

ive seen both of those projects. they look very cool. the only thing was, the frequency responses didnt look all that linear. they were like +-10dB or so for some. that doesnt seem all that accurate? maybe im reading it wrong too.

also, with the 12 shivas, 100dB seems somewhat disappointing, given the amount of drivers. i would think it could do MUCH more!

 

[George W]

Notice that when he gives his frequency response for the shivas he writes, "These were taken to determine the frequency response, not to determine output levels."
Something tells me they can do quite a bit more than 100db.

George

 

[Brian Bunge]

Yes, Thomas has stated that he has not tested their true max output levels as he has a plate glass window he has no desire to replace.

Also, keep in mind that Velodyne's claims of a -3dB point of 16Hz (or whatever) is not at full rated power. Once you start really pushing the sub the servo clamps down on the driver so hard that it looks just like a standard sealed box. One response curve I saw showed an F3 around 35-40Hz. I can't remember if it was TN or someone else, but it was from a very well respected subwoofer reviewer.

 

[Vince Bray]

it just seems to me that it has to be a little more complicated than getting a couple (or more) good drivers, a parametric EQ, a good amp, and an elcosure. i guess thats all there is to retail subs, but im always skeptical when someone says they can build something that costs $5K retail for only $500.

It does. It takes planning, agonizing, execution, etc. But it's worth it, and I have very little desire to do anything more at this point. I am stunned whenever I crank it. Now mine is only a HE15 with passives, with a mere 23mm of linear throw one way it's not quite as potent as a Tumult with 34mm.

You would not be disappointed

 

[ThomasW]

Gee this is become a busy thread

Robert,
You've got mail, and an invite to visit.

FIY everyone,
A standard markup to retail for VERY high end loudspeakers such as Avalon, Wilson, Krell, etc, is basically 9 times manfacturing cost. This I know as fact. Now more mainstream companies such as DefTech, Velo, etc, don't have those kinds of margins.

As George and Brian have noted the big IB SPL chart was just to get baseline plot to start playing with EQ. Since there's a 55 sq ft picture window in the room, I wasn't interested in testing to see if Dan Wiggins 'guestimate', of 130+dB @ 20Hz was accurate