use a PA ampli for sub

[IsakAlexander]

PA sub amp

Wondering if anyone have tried using the amp module from an pa sub in diy-sub intended for home cinema? I got a Montarbo 215SA. There is a HP filter at 37Hz 12 dB and a LP 24dB at 100Hz. Output is rated at 600W 8ohm rms. Tried contacting montarbo regarding removing the HP, all I got was: you could do it if you really want to. Is it worth the effort? Would be nice to put it to some use.

Any ideas?

 

[bottomfeeder]

Crown sound problem !

weird problem ..
I have a Dayton quatro 15" in a sealed 7.3 cubic box .
I ran it with a crown XLS 402 , it sounded OK the amp had plenty of power it could bottom the driver without showing a clip indicator .
BUT ..
Than I bought a dayton Sa240 plate amp $109 free shipping .
Now the sub hits louder ,deeper (like I went from a 12" to a 15")
And the amp is on 1/2 way gain .
Now I dont know why this is .
Does that amp just not provide sub frequencies ?
Is the dampening that BAD on the crown ?
I dont know what the deal is but one thing for sure is I sold the crown ASAP .
I have always looked up to crown as a great product , but what ever the problem was it sure has stoppted me from wanting another crown amp .
Does anybody know why I had that problem ?

 

[bottomfeeder]

?

well I got no help with that problem so I guess home power amps are designed to get the low end out (I heard a adcom 555 will do the trick) .
I read on a forumn here a peavey cs800 is nice or a QSC rmx series is fine, I am just leary of prosound stuff.
My sub is two 12" 4 ohm subs in a isobaric 3.5 cubic box , the drivers effeciancy is 89 db . I need 170 watts per driver .
I was looking at 2 yamaha amps (M-85 & M4) but the dampening is 230 on the M-85 (not posted on the M4) so since those are not much better than the 200 on the Crown XLS I dont know if they are any better ??????????
Any feedback would be appreciated before I spend more money ..

 

[Brett]

PA amps are fine for LF. They are the best value/W going in many cases.

Do not obsess about DF numbers, better yet ignore them. They are measured directly at the amplifier terminals and once even a modest length of cable and connectors is added, the numbers drop considerably.

 

[bottomfeeder]

PA amps are fine for LF. They are the best value/W going in many cases.

Do not obsess about DF numbers, better yet ignore them. They are measured directly at the amplifier terminals and once even a modest length of cable and connectors is added, the numbers drop considerably.

I think I am best just using something thats recomended .
If I would have read up on the crown XLS first , I would have not bought it for subs ..

 

[Brett]

I think I am best just using something thats recomended .
If I would have read up on the crown XLS first , I would have not bought it for subs ..

Recommended how and by whom?
Why would you not use the Crown?

My recommendations are based upon experience of using them as HT amplifiers. I have many from Yamaha, Quest, Jands, Samson, PL and QSC.

Spend some time on the HT DIY forums and the Behringer EP2500 is king of value. It has been tested independently and performed well.

 

[bottomfeeder]

Recommended how and by whom?
Why would you not use the Crown?

My recommendations are based upon experience of using them as HT amplifiers. I have many from Yamaha, Quest, Jands, Samson, PL and QSC.

Spend some time on the HT DIY forums and the Behringer EP2500 is king of value. It has been tested independently and performed well.

I read forumns like this one and quite a few people say the Crown XLS 402 is not a good choice for subs , I also go to a large prosound store where they buy and rent complete systems if you plan on setting up a concert and need mixers, lights, amps, cables, mics, speakers etc .
Plus they have a large pro-sound dept .
Between the staff I talk to there is combined 50+ years of setting up concert experiance .
Plus they have a consignment shop , so they are not salesman who work on comission but rather people who have heard all the problems , and can help fix them w/out draining your wallet like some shops like to do .
Thanks for advice on the Behringer Ep 2500 I will look into that
Crown is good stuff but for subs I should have bought a macrotech a K1 or a ce4000 .

 

[Brett]

Garbage. The Crown will be fine. PA people know nothing about HT and their idea of a 'sub' is very different to a HT. I've run and built a lot of PA's and there is very little difference between pro amps of similar specs/power. Crown are a respected name as are Yamaha, QSC (insert many other brands here) etc. Any of them with enough power into rated load will be fine and indistinguishable from another for HT sub use.

Edit: did they actually give you a technical reason why they feel the XLS series are not suitable?

 

[bottomfeeder]

Garbage. The Crown will be fine. PA people know nothing about HT and their idea of a 'sub' is very different to a HT. I've run and built a lot of PA's and there is very little difference between pro amps of similar specs/power. Crown are a respected name as are Yamaha, QSC (insert many other brands here) etc. Any of them with enough power into rated load will be fine and indistinguishable from another for HT sub use.

Edit: did they actually give you a technical reason why they feel the XLS series are not suitable?

My second sub is a dayton quatro 15" I was first running it on one side of the crown XLS 402 when I switched the amp to a dayton sa240 plate amp (that amp has no equalization)

It sounded deeper hit harder than the crown did , I did not change the subs location (just the amp) .
It was a better sound at all volumes .
Why do you think that was ???
I did not ask a technical reason from there .
At the music store they would recomend what they hear and what people buy to run there subs .
I realize some folks there dont realize what my type of subs a HT wants .
but they do know what sounds better in a A/B setup for lots of stuff , I think the differances you hear driving something like the 18" JBL subs will reflect well on home theatre subs also .

 

[Inductor]

Hi Brett, guys.
I once post a thread on the Amp forum on this new QSC GX5 amp H-class, and it's flat 20-20K response (to 40K) with an onboard xover for subs at 100Hz and no distortion at all. Do you think it will work for _HiFi with audiophile quality (and also as PA/DJ). It has balanced XLR and unbalanced RCA entries. I have plenty of tests from magazines were they compare them.

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