Using a 5 Channel Amp To Bi-Amplify? (1 Viewer)

[Brett DiMichele]

Hey All,

It has come time to do some upgrading and my focus is for
both movies and music I want to do both equaly as well as
the other.

My problem is that my TX-DS787's 100wpc does not power my
AR9 mains very well. Complex Passages that are heavy on the
lows tend to send the Receiver into Thermal OverLoad Protection.

If you compare the AR9 to the AR5 the sole difference is
that the AR5 contains one 175 Watt Mono Carver Sunfire TDC
Amp in each speaker cabinent who's sole duty is to drive
that 10" Bass Reflex Subwoofer.

I didn't want a "powered sub" because there is far more
flexibility with non powered for setup purposes. So I find
myself wanting to Bi-Amplify my 9's.

I have been pondering how I want to go about doing this. In
one respect I could go for straight out 2Channel and buy 4
moderate MonoBlock amps like the nOrh LeAmps or I could go
with a more Home Theater biased 5 Channel Amp which could
be setup for 2Channel and Home Theater.

So what I am thinking is could I do this... I want the
Parasound HC2205-AT which delivers 220 Watts Per Channel
by 5 Channels. I was thinking that I could use this in two
diffrent and unique setups. On the one hand I can run all
of the seperate channel outputs of the 787 into the ParaSound
and that would hook me up with plenty of power for Home Theater.

And then I could also use Left/Right Front and Left Right
Rear Surround's all linked together to the Left/Right Front
outputs of the 787 so that I could send 440 Watts to each
AR9, 220 Watts for the Sub and 220 Watts for the Mids/Highs
in a Bi-Amplify config.

Both ways the volume and everything would be controlled via
the 787 wich saves me from having to buy a seperate Tuner
and PreAmp for 2Ch. I will use the 787 as the source switcher
and Tuner but I am sure I could hook this all up to be switchable
for 2Ch or Multichannel.

Of course I would have to use splitters so that I could plug
all these outputs into the Parasound.

Am I crazy ? Or is what I am concieving founded in logic?

Any suggestions?

My ears are open.

 

[John Kotches]

Brett,

Might I suggest you start with single-wiring your Front L/C/R and driving the passive subwoofer with the 4th channel instead? This leaves one unused channel, but still might be worth pursuing.

You might find that the 220wpc/8ohms of the Parasound amp will be miles ahead of the 100wpc from your receiver, which would eliminate the biamping.

Just something to consider.

Regards,

 

[WillieM]

I am currently using a Denon AVR882(90wX5)reciever and plan the following upgrade (which I did pass by my AV consultant who said it sounded like a stellar idea).

Purchasing 2 new amps; the Parasound HCA-1205A (140wX5) and the Parasound HCA-1000 (125wX2). Using the Denon as a pre-pro only.

I am running PSB Image series all around (5T fr L/R, 9C ctr, 2B rears). The front 5T's are bi-ampable.

I will use the 1205 to run the tweeter/mids up front (less drain on the amp than the woofers) and all other speakers, and use the 1000 to drive only the one 6-1/2" woofer in each of the front speakers. 125W per 1 speaker each should be more than enough power.

The 5ch amp should therefore not be over drainied and the 2ch can most certainly handle 2 speakers.

MSRP on the HCA-1205 is $1199/ the HCA-1000 is $650. total is only $1849 vs the $1999 for the HCA-2205.

 

[Brett DiMichele]

John,

The problem is I have 2 Passive 10" Subs not just one, and
they each need at least 150 watts to run them efectively.

My reasoning behind the 2205 is that 220 watts per channel
will leave me lots of head room and power should never be
a factor after that upgrade.

I could always just buy an external sub and disconnect the
sub portion of my 9's but that kinds defeats the whole reason
for buying near full range towers.

*Scratches Head* I dunno... I like the 2205 anyway so I can
get it and see if I can work it in.. I am sure I can!

I just kinda wanted to see if what I was scheming was doable
or if 4 monoblocks for the mains would be better. Monoblocks
will be more hassle though.

 

[Mark_E_Smith]

Are the AR9s a 3 way speaker? if so you will have a 3 way X-over to deal with also. If not and if you feel like some minor DIY you could buy 2 250 watt sub plate amps and drive them from your sub out on the receiver. I have the Onkyo 787 and a powered M&K sub, the system will hit 108dB clean at my listening position, if I want it that loud. The sub is done at 94 dB though so I am working on that with a DIY sub.

 

[Brett DiMichele]

Mark,

Yes they are 3 Way, But they are set up for from the factory
to do Bi-Amp.

When you BiAmp the 9's the High Side is the Tweet and Mids
the low end is the Sub and they are completly seperated.

 

[Mark_E_Smith]

Then look here
http://www.partsexpress.com/pe/pshow...=300-794&DID=7
you could build a small inclosure for the amp, and run it from the sub out with a "y" rca cable to each amp. The neet thing about this is you have the x- over and phase adjustments and an optional bass boost ( in a diferent part number)and on the plate amp. BTW it does not have to be mounted in the speaker box, lots of guys who build sonotube subs mount them in thier own box. Look here from a fellow HTF admin Patrick Sun
http://www.io.com/~patman/ampbox.html

 

[Brett DiMichele]

Mark,
That is a definate idea to consider, in fact I have thought
about it already. I looked at the remote controled version
of the P.E Plate Amps.. I could easily mount a plate amp
in each cabinent (directly across from the sub woofers) and
I don't think I would affect cabinent volume much at all.
But I kinda want that big ass ParaSound amp!
Sure I could save a ton of money going with plate amps
and then my 787 could send it's 100wpc to those dual 5.25
and 1" tweets which it powers those with ease.. But I dunno
I got the hankerin for one BIG amp.. I have an open space
in my audio rack

 

[Brett DiMichele]

Ya know what.. The more I think about it this would most
definatly be the much easier way to go.. My Onk has enough
headroom to run the center, surrounds and the mids/highs
of the 9's with no problem.. I think I am just going to
order two of the PE Plate Amps and mount them in a rack
mount enclosure and mount them in my audio rack and just
run the speaker lines over to my 9's.. I really don't want
to mount them in the 9's because well I just don't want to
do that..

For now I think this setup will cure my problems.. Later
I will step up to a larger 5 channel amp.

 

[Mark_E_Smith]

Then you will also need 2 active subwoofer crossovers. You have me thinking down the road of active cross-overing my system. I am a DIY at heart and am in the process of redesigning my system to be my designs. Just finished my center channel, next is the sub(s). Then it is off to the mains. Good luck

 

[Brett DiMichele]

Mark,

Won't the Bass Management in my 787 be sufficient for the
time being?

 

[Mark_E_Smith]

What is your understanding of the bass managment of the 787, I thought it only applied to the DTS, DD and THX settings. I may be wrong, cant find anything in the manual.

 

[Brett DiMichele]

Mark,

I can't find anything in the manual either but I am assuming
that when you set it to "Subwoofer Yes" that it applies the
appropriate crossover all the time even in Direct or Stereo
Mode.. I could be wrong.. I will have to look into it further.

 

[John Kotches]

Mark,

Do not underestimate matched amplification, given that you have a pair of 10" passive subs to drive, my recommendation would be:
L/C/R + the subs.

Regards,

 

[Mark_E_Smith]

John, my only concern would be lack of a crossover for the subwoofer, his concept is great and I generally agree with his approch. If the receiver rolls of the sub with a 2nd order at 100 to 125 Hz and has some kind of high pass at 15 to 20 Hz this would be fine and you wouldnt need an additional x-over.
Brett, I know allot of people use a crown amp to run their homemade subs, you might ask the x-over / bass management question over at the DIY / advanced projects section of this forum.

 

[John Kotches]

Mark,

Yes, I've made the assumption the receiver has a competently designed filter for the subwoofer. If it's THX badged the high pass portion of the subwoofer filter will be in place (by requirement).

The Low-pass filter (in this case your basic subsonic filter) could easily be placed inline between the receiver and amplifier.

The catch is that there is material being delivered below 16Hz nowadays.

Regards,

 

[Brett DiMichele]

John,
Seeing as my 10's will never see 16hz I guess I won't know
what I am missing till I go to dedicated sub woofage!
I will eventualy pick up one of AR's ARS500's if I can find
one for the right price and do some experimenting. At that
time I will need better bass management to be able to run
a dedicated "LFE" sub and use the mains just down to a certain
cutoff.
This stuff gets confusing!

 

[Mark_E_Smith]

Ok rereading the posts I missed the post about you using the PE plate amps. They have all you need. I would use the sub out to the PE plates and I bet that will sound great! Most likely as good as the AR5s
John, there have been reports that some of the new DVDs (Lord of the Ring, and U457(?)) are infact going down into the teens esp on explosions, but that is getting into the range of mechanical shakers.
BTW Brett I looked at your HT set up on your site, I have the same a/v rack as you. Did you have a pronto? Also you might consider building your own sub(s)later. There are some neat drivers out there and you can get an incredible sub for 1/3 the price of a comercial sub.

 

[Brett DiMichele]

Mark,
I figured the PE Plates had all I needed that was why I was
scratching my head over the need for seperate bass management!
I bet with the PE Plate Amps they will OUTDO the AR5's!
I had a Sima SUR-20 (Same as the Crisp Solutions UC515)
now I have a Pronto Pro TSU6000 gawd I love that remote!
Cool audio rack.. For the price! Of course Salamander makes
some that are to die for.. But the prices.. Yeowch!
It suits my needs. Holds all the junk!

 

[John Kotches]

Mark:
The THX intro and Phantom Menace are in the 10Hz range......
Yee haa... Just a few Hz lower and we'll have DC to reproduce
Regards,