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I have a 1250-watt plate amp, want to build sub!


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35 replies to this topic

#1 of 36 Robert Cowan

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Posted November 13 2003 - 04:14 AM

hey everyone. this is about my first time posting in this forum (although i have been reading it for awhile). I'm a somewhat veteran DIY'er with amps and such, but have yet to really build any speakers or subwoofers... I just came across a sub plate amp for a velodyne HGS18, and it needs a good home Posted Image

i already have a deftech supercube reference in my theatre room. it has usable output down to like 15hz, so it goes LOW. i want something to augment some of the higher bass frequencies (~60hz+), and have a bit of quick punch up there. i was thinking like 2 10's or something? im just not sure the difference between sealed, ported, etc... i want it to be clean. having HUGE outputs would be nice, but my other sub has that covered already.

since the plate amp was free, im looking to not really spend that much on drivers. if there is a cheaper driver that performs reasonably well, thats what im in for. i would love to keep the project price pretty low. i have tools (band saw, scroll saw, circular saw, router, router table, dremel on steroids, etc...), so thats not a problem. i would just need MDF, stuffing, maybe ports, etc... i can get dynamat at cost too, so i would be lining the inside with that...

phew! any suggestions guys?

#2 of 36 Robert Cowan

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Posted November 13 2003 - 04:43 AM

i should also include that im a maggie owner, so it will need to integrate well with them. (thats why im thinking maybe 10's?)

#3 of 36 ThomasW

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Posted November 13 2003 - 07:01 AM

I posted a fairly lengthy reply but edited it when I saw you had a active 2 page thread going on HERE

BTW, IMO products like Dynamat are a waste of time and money for a DIY HT sub. The wavelengths involved render it basically useless. If you really want the best material for lining a sub get 1/2-3/4" thick high wool content felt gasket material.

Here's a pic of what the felt looks like when it's installed

Posted Image

#4 of 36 Robert Cowan

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Posted November 13 2003 - 01:33 PM

i would do dynamat in addition to a wool or something...

also, i dont think that the plate amp has anything in it except for just an amp. however, i will check that out.

#5 of 36 ThomasW

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Posted November 13 2003 - 02:53 PM

Dynamat is great for damping resonances on metal. For properly designed and built wooden subwoofer box it's all but useless.

BTW, if you go to the Dynamat website no where do they recommend it for home audio

#6 of 36 Robert Cowan

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Posted November 13 2003 - 03:18 PM

interesting. i never knew that. of course, i have never build a speaker before either. i have used it to damp cd players, etc... that helped a lot. but never with speakers. thanks.

#7 of 36 Vince Bray

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Posted November 13 2003 - 03:20 PM

I don't blame you for coming here though, since you only got a couple of semi-helpful responses. If I was faced with that, I would get a Tumult, box it to your liking (that would be PRs unless you can stand a big box), and then once you notice that you don't need the deftech anymore, sell it and you'll still be ahead of the game financially. With that kind of wattage and a Tumult, you should have a one-size-fits-all bass solution, and a world class one at that. Another thing that's not been mentioned is researching what kind of filters are built into the amp, and whether they can be disabled/modified. Of course, you could go with multiple of other 15" and get the same output, but with a bigger box.

at least that's my 0.01 (adjusted for inflation)

#8 of 36 ThomasW

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Posted November 13 2003 - 04:38 PM

Quote:
I don't blame you for coming here though, since you only got a couple of semi-helpful responses. If I was faced with that, I would get a Tumult,
According to the DIYaudio forum thread he only wants to spend $200 on a driver/drivers for his mid-subwoofer

He's running Maggie 1.6QR's. These are happiest with a 80-100Hz XO point to a woofer. Taking the bass load off the panels makes Maggies much happier.

The problem is going to be getting good integration with the midsub, his current sub and the mains. The best solution will be stereo mid subs, so probably a 10" on each side.

This brings up the issue of line integrating a line source with a point source. This is only possible at a single fixed distance from the speakers, given the -3db roll-off rate with doubling of distance with a line source vs -6db roll-off for a point source.

An additional issue will be that fact that one should take the really low bass out of the midsub. This means using a real 2-way XO, not the XO built in to the plate amp.

#9 of 36 Brian-K-Owens

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Posted November 14 2003 - 02:34 AM

Any thoughts on the Usher 8945 (7")?

(4) of them would be $340. This 7" can make good bass all the way down into the mid 30 Hz range, and the upper XO point could be as high as needed to integrate with the maggies.

I read the other post. Just curious why it seems like you are using some nice equipment, and then I read "pyle drivers" in that post. Wait until you can afford a little more and get something that is not going to degrade the sound you have now. . . .

Brian
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#10 of 36 Robert Cowan

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Posted November 14 2003 - 05:28 AM

hehe, in regard to the pyle drivers, i just threw that out really...

im not looking to replace the deftech at all. if anything, i want to strengthen the upper mid-bass region.

it does low bass FINE. in a couple months, its getting traded for a velodyne DD-18, which will hopefully obliterate just about anything i could build. (plus it has a remote and onscreen display, cant get too much cooler than that).

but anyway... why not 2 10's? (since the pyles suck i guess, i will only have a budget for 2 decent 10's.) i should also mention (as i did in the other forum), i can get infinity car subwoofer drivers for CHEAP. it appears some of their higher end drivers are pretty nice, but at retails of $400+ each, normally it wouldnt be an option. but i can get a pair for around $200, so that would be within budget. if its not a good idea, thats fine too.

so, once again, i dont want to build the ultimate sub, or anything to replace the deftech. thats NOT the idea here. just to build something decent to augment the deftech in the upper mid-bass region. there is just a slight gap where the maggies cut off and the deftech starts shining. if i had to, i could make a crossover that would actively separate 100-40hz and 60-20hz and send it to respective places...

#11 of 36 Brian-K-Owens

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Posted November 14 2003 - 05:42 AM

I read you were looking for upper midbass region. That is why I suggested the 7" drivers.

A pair of 10" would work fine. If you can get the Kappa 10.1's for $100 each, I will take a couple too Posted Image) I love those drivers. Had a pair in my truck with 1000 watts running them. . .man oh man were they nice for 10" drivers. Might be the perfect thing in a small sealed box.

Another good driver might be the RE8. www.respl.com

Brian
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#12 of 36 Brian Bunge

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Posted November 14 2003 - 06:51 AM

I'd say wait until you get the new Velo (I can't imagine spending that kind of money on a sub, ouch!) and see if it works better than the DefTechs. I'd imagine it would have to. Then if you still feel the need to augment the upper bass frequencies then do so.
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#13 of 36 Robert Cowan

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Posted November 14 2003 - 09:41 AM

Brian,

who said i was paying for the sub? Posted Image

this is mostly a "because i can" project. the sub plate amp was free and i might as well put it to good personal use. i dont want to build crap, but then again, i dont want to spend much and i dont need much...

i think doing the two infinity subs would probably be the way to go... what about 3 10's? i can get the 10.1's for around $75, maybe i could do 3? or would two be plenty?

#14 of 36 Greg_R

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Posted November 14 2003 - 10:05 AM

Why don't you just drop a Shiva into an enclosure? It has great upper-bass response. (1.2kW would be gross overkill in terms of amplification)

#15 of 36 Jason_Me

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Posted November 14 2003 - 10:31 AM

A pair of line array subs using 4 Dayton 8" DVC's in each sub should do the trick. They're going for $20 each right now.

http://www.partsexpr....D=166913&DID=7
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#16 of 36 Robert Cowan

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Posted November 14 2003 - 11:27 AM

hmmmm,

i like the sound of doiing a line array of daytons. i could easily do 4 of them. isnt the shiva a bit pricey? plus, i kinda want something a bit different from just a sealed box sub. everyone has one, and i already have one. but too much creativity costs too much $$. plus, 8's are definately the frequency range that im trying to fill in for.

#17 of 36 Brian Bunge

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Posted November 14 2003 - 01:35 PM

You've got a 1K+ amp but want to use crap drivers? A couple of Shivas would be a minimum requirement, IMHO. Multiple 8's might work well too, but how many would you have to buy to equal the output of a single Shiva?

A single Shiva in the right enclosure with a 250W amp (like say the Adire Dharman) is equivalent to an HGS15. That should give you an idea of what you'd get if you went with something like a Tumult.

Here's an idea. Sell the DefTechs, forget the Velodyne and build a first class sub. You'll have less money invested (assuming you have the tools and know how) and have a superior sub than what you have now or plan to have. Or you could continue with your current course and end up with a decidely mediocre creation.

I don't mean to sound rude, but I'd rather see you end up with something you could really be proud of instead of some cheap ass blown drivers.
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#18 of 36 Robert Cowan

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Posted November 14 2003 - 01:56 PM

how much does a shiva driver cost?

i just have a hard time believing you can build a better sub than a velodyne DD-18... sure, i could have quite a budget if i did sell the deftech, but i want to know what im getting into first.

#19 of 36 Brian Bunge

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Posted November 14 2003 - 02:02 PM

The Shiva is only $125. The Tumult is $499. At their respective price points there are very few drivers that will compare in performance.
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#20 of 36 Robert Cowan

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Posted November 14 2003 - 02:07 PM

ok, so the shiva is within my range... you are saying if i so a sealed box with the shiva and the velodyne sub, i will have something that will outdo (?) my deftech that i have now? if that is the case, ill try it. and if it works out, ill sell the deftech, and use the money to build a dual tumult sub.