Conceptualizing subs for my theater build - Inuke amp or ATI stereo amp? - AVS Forum
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post #1 of 14 Old 07-18-2014, 11:56 PM - Thread Starter
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Conceptualizing subs for my theater build - Inuke amp or ATI stereo amp?

I'm in the process of remodeling a home right now. We're converting a two car garage into a home theater. Dimensions are 21 long x 18 wide x 9.5' high = 3591 cubic ft.

I've got some existing Bohlender Graebner 520i radia speakers that I will be using as my mains with a 220 center channel. I've got an ATI 1505 5 channel amp for the system. I'm probably going to wire it up for Dolby Atmos however and install extra speakers and get either another ATI or Emotiva amp.

I have a HSU TN1220 sub with their 500w monoblock amp, but I have a feeling this will NOT be nearly enough bass for the room. So I'm thinking about building my own. I have plenty of vertical space but I don't want the subs to stick out from the wall so much as I'd like to have a false wall for the projection screen. If the false wall is much more than 2 feet out from the rear wall, I'll end up with a square room which I understand is not desirable.

The other issue is regarding amps. I see that the Inuke is a favorite here because it has DSP. In my experience usually quality amps have heavy transformers. The old saying is a heavy amp is a good amp.

My questions are:

1) The Inuke is something like 12 lbs. I have a spare ATI 1502 which puts out 225w @ 4ohms into each of two channels. The thing weighs 40 lbs. Would this not be a superior amp to a relatively light weight Inuke? And since it does not have DSP, can I buy a cheap DSP to go with it?

2) What kind of sub design would work in my scenario? I would prefer something rather shallow front to back but it's ok if it's a bit taller. I could also lay the sub on it's side rather than having it vertical.

Thanks in advance. I've never built a sub before but I have a cabinet builder who's doing custom closets for me in trade. I'm sure I could get him to cut me the panels for the sub.
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post #2 of 14 Old 07-19-2014, 12:21 AM
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jbrown has two 6000dsp's, and when I was there, they never crapped out, but we didn't give the subs all they had either, as it would have ripped his house apart...


On How-To-Train-Your-Dragon we stopped at 113db @ 18hz, it coulda pushed 120db I'm sure...


The best amplifier I've been able to find thus far is a Lab Gruppen china clone, at over 8000watts it seems to have what it takes for any job, and is still cheap-ish. The only problem is getting one that WORKS!!!
The second best amplifier I own is a Crown iTech 8000.

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post #3 of 14 Old 07-19-2014, 12:29 AM
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the old transformers were good and fine.


done right, switch mode power supply is just as good, if not better. long term reliability remains a questionmark for the behringers, but so far, so good.


lab gruppen, crown, qsc, powersoft, at al have mostly abandoned the 'big iron' amps in favor of the greater efficiency afforded by the newer technology. these are the brands that power rock concerts and imax theaters. behringer's model in many cases is to copy other's designs, save on the r&d and support, and sell at a budget price to take market share. as a result, you can get some pretty good stuff, cheap. not the best, but pretty good value, particularly at the lower price points.


there are a ton of bass options. a pair of ported 18's can be done pretty cheap (stereo integrity 18ht or Dayton 460ho), inuke3000/6000dsp amp depending more on what is best match for the driver impedances, in big low tuned ported cabs is a proven model.


one possibility Large Ported Dayton HO18's


can be pretty much made into any shape you want with the same performance so long as cab volume remains about the same. lots of shallow builds that are large. jbrown15 has some cabs that you might like. another guy is working on something quite similar. not sure if he would mind me sharing his concept.


i'd suggest that you upgrade your mains to something with controlled directivity and high sensitivity. the speakers that you have may not be the best for bringing home the imax experience.


read up on room modes as that will influence the bass response quite a bit and in ways that aren't always obvious.


search around a bit and read through some of the build threads that are kind of like what you want to do and folks will be happy to help.


if you really want to do it right of course, a small investment in some measuring gear will go a long way (even an spl meter can be used with test tones to get some idea of what is going on).


here is jbrown15's build:


LTD-M18 Sub Build


plasmad pocket sub is another oddball subwoofer designed with very shallow depth. definitely a creative solution.


The plasmad pocket sub


good luck.

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post #4 of 14 Old 07-19-2014, 01:08 AM - Thread Starter
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Thanks for the links! I've seen multiple threads on Marty Subs and I figured that some variation would likely work for me.

I'm partial to the BG Radia's because first and foremost I'm a 2 channel (well....2.1) lover. And I love the ribbon's in the BG's. They are the people that made the ribbons for Martin Logans. It's a really detailed, clean, airy sound. I'm not sure if it'll hit reference IMAX levels, but in my old home theater they got pretty dammed loud with the ATI 5 channel amp. If at all possible (and for monetary reasons) I'd like to keep my mains for now. I can always upgrade later or build out a separate system. I was going to re-build my analog system anyway.

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Originally Posted by LTD02 View Post
the old transformers were good and fine.


done right, switch mode power supply is just as good, if not better. long term reliability remains a questionmark for the behringers, but so far, so good.


lab gruppen, crown, qsc, powersoft, at al have mostly abandoned the 'big iron' amps in favor of the greater efficiency afforded by the newer technology. these are the brands that power rock concerts and imax theaters. behringer's model in many cases is to copy other's designs, save on the r&d and support, and sell at a budget price to take market share. as a result, you can get some pretty good stuff, cheap. not the best, but pretty good value, particularly at the lower price points.


there are a ton of bass options. a pair of ported 18's can be done pretty cheap (stereo integrity 18ht or Dayton 460ho), inuke3000/6000dsp amp depending more on what is best match for the driver impedances, in big low tuned ported cabs is a proven model.


one possibility Large Ported Dayton HO18's


can be pretty much made into any shape you want with the same performance so long as cab volume remains about the same. lots of shallow builds that are large. jbrown15 has some cabs that you might like. another guy is working on something quite similar. not sure if he would mind me sharing his concept.


i'd suggest that you upgrade your mains to something with controlled directivity and high sensitivity. the speakers that you have may not be the best for bringing home the imax experience.


read up on room modes as that will influence the bass response quite a bit and in ways that aren't always obvious.


search around a bit and read through some of the build threads that are kind of like what you want to do and folks will be happy to help.


if you really want to do it right of course, a small investment in some measuring gear will go a long way (even an spl meter can be used with test tones to get some idea of what is going on).


here is jbrown15's build:


LTD-M18 Sub Build


plasmad pocket sub is another oddball subwoofer designed with very shallow depth. definitely a creative solution.


The plasmad pocket sub


good luck.
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I'm no amp expert but as I understand the only reason for a transformer to exist AT ALL, is to either step up the 120v to 200v so that it can more easily be rectified into 200v DC, or to
step down the AC to 5-20v for the rest of the small circuits.

Every piece of wire or circuit that you have between the wall socket and the speaker is just another situation where the total efficiency of the design is reduced.
By having a SMPS that can handle super-high current at 90% efficiency the need for big blocks disappear.

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post #6 of 14 Old 07-19-2014, 11:31 AM
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it's not the top end that would be the concern, well most of it anyway.


the subs need to match to something for the mid-bass.


having four 18's handoff to 4 6.5" drivers may not provide the mid-bass experience. the 50-150hz region is pretty important. you'll likely have the lower side of that covered. it's the other half that i was thinking about. at 84db 1w1m, there is no hope of getting uncompressed peaks to the seats.


this is one reason why so many folks are coming back to the large woofer designs that were popular in the old days.

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post #7 of 14 Old 07-19-2014, 12:08 PM
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Quote:
Originally Posted by video1 View Post
My questions are:

1) The Inuke is something like 12 lbs. I have a spare ATI 1502 which puts out 225w @ 4ohms into each of two channels. The thing weighs 40 lbs. Would this not be a superior amp to a relatively light weight Inuke? And since it does not have DSP, can I buy a cheap DSP to go with it?
I have a similar question: I realize the inuke is attractive because of its DSP, but does that mean that typically people using the inuke DO NOT use the minidsp? Does the inuke allow the same basic DSP range as the minidsp? Like I am a n00b. Sorry for stupid questions. I just had a similar curiousity along the same line of question that video1 has; is there a cheaper then inuke good amp with NO DSP that one might use and then supplement minidsp with it? Just trying to learn the ropes here.

ALSO: If I want to build two subwoofers do people normally size their inuke for two or buy two separate inukes? Like they come in different wattages

Thanks so much.

Last edited by skipford; 07-19-2014 at 12:17 PM.
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post #8 of 14 Old 07-19-2014, 12:46 PM
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the inuke software is very good. it can do all the stuff that folks need for ported subs, such as protective high pass filters, and lots of equalization. no need for mini-dsp with inuke dsp.

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post #9 of 14 Old 07-19-2014, 01:34 PM
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The only advantage the mini-dsp has is that it can shape below 20hz, the inukeDSP and DCX and most other DSP/EQ systems cannot.

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post #10 of 14 Old 07-19-2014, 03:18 PM
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for the most part, the filter that is most important to push under 20hz is the high pass filter in low-tuned applications. in those instances, there is a workaround for both the dcx and the inuke dsp.


How to extend the high pass filter below 20hz in DCX2496

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post #11 of 14 Old 07-19-2014, 08:34 PM - Thread Starter
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Hmmm, I think I understand what you're getting at.

Since I'm enamored with the speakers as they are, would it be possible or practical to supplement the mid-bass? Or would that create problems with having a capable crossover so that everything is integrated smoothly?

Quote:
Originally Posted by LTD02 View Post
it's not the top end that would be the concern, well most of it anyway.


the subs need to match to something for the mid-bass.


having four 18's handoff to 4 6.5" drivers may not provide the mid-bass experience. the 50-150hz region is pretty important. you'll likely have the lower side of that covered. it's the other half that i was thinking about. at 84db 1w1m, there is no hope of getting uncompressed peaks to the seats.


this is one reason why so many folks are coming back to the large woofer designs that were popular in the old days.
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post #12 of 14 Old 07-19-2014, 09:18 PM
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a lot of folks have experimented with that with varying degrees of success. such units are often called mid-bass modules. as you note though, the trick becomes how to get seamless integration with all those different drivers/amps.


another option and very much less frequently done would be to cross the subwoofers over very high, such as 150-200hz. but as you might guess, the drivers that provide the best bottom end don't always produce the best top end, which brings it all the way back around to the beginning.

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post #13 of 14 Old 07-19-2014, 09:33 PM - Thread Starter
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I suppose one solution would be to use some sort of filter so that the BG's only put out above 200 Hz. Then the mid-bass and sub's would handle the rest. The trick would still be how to do a decent seamless crossover.

I know a home theater guy that is close to the insiders at BG. I think I'll run this question by him.

Quote:
Originally Posted by LTD02 View Post
a lot of folks have experimented with that with varying degrees of success. such units are often called mid-bass modules. as you note though, the trick becomes how to get seamless integration with all those different drivers/amps.


another option and very much less frequently done would be to cross the subwoofers over very high, such as 150-200hz. but as you might guess, the drivers that provide the best bottom end don't always produce the best top end, which brings it all the way back around to the beginning.
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post #14 of 14 Old 07-20-2014, 01:05 PM
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With regards to sizing amplifier, for example the inuke; knowing that I am going to power two subwoofers, it is cheaper to get a larger ampacity unit. Is this normal? And power two subs and use DSP which I assume can handle two channels separately, or does everyone always get individual inukes for each sub? Also for a horn such as the microwrecker or lilwrecker, what maximum ampacity is usually used?
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