# has anyone ever... ?



## jeremy7 (Feb 7, 2008)

have any of you ever built a two way with a powered sub in each?
I was thinking of building this with the two way passively crossed and the subs bi-amped and actively crossed. 
I was going to buy a separate amp for the subs, but then i decided I wanted the sub amps to be in the speakers. Are plate amps my only realistic option?
I wanted to bi-amp so I had control over the phase, and also my design called for the cross to be around 100hz or so, and I wanted to avoid huge, expensive, and sonically intrusive caps/inductors.
If Im not mistaken sonus faber builds a speaker using this concept.
Anyway Im curious if any of you have done this, if you have any advice, if you think its a good idea, if you know of any plate amp substitutes (not that im completely against the plate amp, i just wanted the amp to be more internal), or any answers to questions that I haven't thought to ask.
thank you in advance


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## JCD (Apr 20, 2006)

I haven't done it, and can't think of anyone who has done a DIY version of what you're thinking about doing.

I thought i'd put in my 2 cents regarding your plate amp question:

I think a plate amp would work best for what you're trying to accomplish. Any amp, as long as it's powerful enough, can power the speakers, but where to put it is the thing. I'd go with a plate amp if it were me.

JCD


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## jeremy7 (Feb 7, 2008)

thank you


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## Guest (Aug 6, 2008)

hi, i am designing a very similar system myself at the moment with a mtm 2way and a subwoofer with a plate amp built into the speaker itself, its not unlike a 2way with a seperate subwoofer, but just built in and neat. i decided to go with a sealed cabinet for sub and the mtm to get a smaller box and use the bass boost and volume to match it to the mtm.


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## Bill Fitzmaurice (Jun 14, 2008)

jeremy7 said:


> have any of you ever built a two way with a powered sub in each?
> I was thinking of building this with the two way passively crossed and the subs bi-amped and actively crossed.


My workshop speakers are MTMs in the same box as horn loaded subs. Good for music, but I wouldn't put subs in the same boxes as tops for HT, the extra octave of extension required is best achieved through boundary loading and that option is very limited with the tops above the sub.


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## jeremy7 (Feb 7, 2008)

Bill Fitzmaurice said:


> My workshop speakers are MTMs in the same box as horn loaded subs. Good for music, but I wouldn't put subs in the same boxes as tops for HT, the extra octave of extension required is best achieved through boundary loading and that option is very limited with the tops above the sub.


Bill, thank you for the response. Would you briefly explain "boundary loading", I'm not familiar with the term. If I had to guess, I'd assume that it had something to do with separate enclosures for the sub vs. the mid/high. If thats the case, I was intending to seperate the two. I dont think I specified that in my original post.


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## Bill Fitzmaurice (Jun 14, 2008)

jeremy7 said:


> Bill, thank you for the response. Would you briefly explain "boundary loading", I'm not familiar with the term. If I had to guess, I'd assume that it had something to do with separate enclosures for the sub vs. the mid/high. If thats the case, I was intending to seperate the two. I dont think I specified that in my original post.


Boundary loading is using wall placement to gain 6dB versus middle of the room, and corner placement to gain 12dB. Then there's the matter of room modes, all of which are reasons to have the flexibility of sub placement that separates gives.


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## jeremy7 (Feb 7, 2008)

Bill Fitzmaurice said:


> Boundary loading is using wall placement to gain 6dB versus middle of the room, and corner placement to gain 12dB. Then there's the matter of room modes, all of which are reasons to have the flexibility of sub placement that separates gives.


perfect explanation, thank you


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