Dynamic requirements

[Vaughan Odendaa]

Hi there,

I've always wanted to know how effective a very high powered amplifier would be (example : 200 watt per channel or greater) dumped into a speaker set to small 80 hz crossover.

I think we can all agree that more amplifier power will better control the bass drivers ability to track transients and just allow better dynamics overall. But how relevant is this when the speakers are high pass filtered and set to an 80 hz crossover ?

I own Jamo C803 speakers (reviewed on Audioholics awhile back) and the rest of the Concert range to compliment a full featured home theater system. I am currently using a crummy AV receiver delivering 80 watts per channel (into 8 ohms). The speakers have a nominal impedance of 6 ohms.

I am high passing each speaker and have chosen an 80 hz crossover. I understand the merits of high power amplification but I'm not sure how relevant this all becomes when high passing since the demands placed on the amplifier (and speakers) are greatly reduced.

Is there relevance in using a Parasound 250 watt per channel power amp to drive my Jamo C803 home theater system if I'm setting speakers to small ?

--Regards,

 

[mazersteven]

You make reference to the bass driver. I may be wrong here, and please someone correct me if I am. But don't the mid-range driver, and especially the tweeter benefit also?

 

[Vaughan Odendaa]

Well, the bulk of that power from an energy distribution point of view would be primarily "fed" to the woofer sections. If the low bass sections are high pass filtered and no longer require huge current draws then is there still reason to use huge power amplifiers ?

I have not used a big power amp (high pass filtered) then used on a pair of book shelf speakers so I can't really comment on the benefits. But for those that have (not necessarily restricted to just book shelf speakers), comments would be appreciated.

--Regards,

 

[mazersteven]

Is there relevance in using a Parasound 250 watt per channel power amp to drive my Jamo C803 home theater system if I'm setting speakers to small ?

IMO these would be good amps to drive your Jamo's.

Parasound A23
http://www.parasound.com/halo/a23.php

Rotel RB-1070
http://www.rotel.com/NA/products/ProductDetails.htm?Id=11&Tab=2&Pic=1

Maybe look for a couple of these pre-owned

Bryston PowerPac 120 SST
http://www.bryston.ca/pp120sst_m.html

 

[Vaughan Odendaa]

Thanks for the comments. I was actually thinking along the lines of the Parasound 5250 power amp (250 watts per channel x 5 -- 8 ohm). I am also wanting to get myself the Onkyo 805 AV receiver and use that as a preamp.

I mean, I want to upgrade from a Yamaha RXV-450. Talk about crummy. But if the results will not warrant the expense then I don't know if I should upgrade to this level. My speaker system is not considered cheap (relatively speaking) and I don't want to do injustice to it.

--Regards,

 

[mazersteven]

Thanks for the comments. I was actually thinking along the lines of the Parasound 5250 power amp (250 watts per channel x 5 -- 8 ohm).

I don't think you need to step up to the 5250. I would say the 5125 would be fine. Maybe someone else will jump in with a recommendation.

Or the Emotiva LPA-1 $449.00 Special Price!
http://www.emotiva.com/lpa1.html

 

[TLS Guy]

Power divide

I have commented on this before. Everybody thinks the power is all in the last two octaves. That is just not true. The power divide is 400 HZ. So power needs to be distributed equally above and below 400 Hz. Most systems have inadequate power above 400 Hz and that is largely a speaker problem. However from reading comments on these forums I think there are more and more people are under the misapprehension, that they can have a 400 watts sub and small low powered satellites.

Now all the front speakers need to have plenty of beef. When looking at systems in dealers, I find the center channel so often really lets the side down. Now that needs to have power handling at least in the ball park of the front left and rights. Now that's a tough nut to crack as there are always some space constraints. If I had to point to the speaker most often preventing the system reaching full potential, than nearly every time its the center channel speaker.

 

[mike c]

IIRC, the rx-v450 doesn't have pre-outs, nor is it up to date to todays "requirements"

why don't you buy a new receiver first, one with pre-outs, with the new features you want, and with a little bit more power ... before you even consider external amps.

 

[mazersteven]

IIRC, the rx-v450 doesn't have pre-outs, nor is it up to date to todays "requirements"

why don't you buy a new receiver first, one with pre-outs, with the new features you want, and with a little bit more power ... before you even consider external amps.

He said he wants to purchase the Onkyo 805.

 

[Vaughan Odendaa]

TLS Guy, so then are you telling me that more than enough power will benefit me even if I high pass all main speakers within my system ?

My center speaker is quite decent. Power handling of 160 watts long term and 320 short term. The book shelf speakers have a power handling figure of 125 long term and 240 short term.

If I upgrade my power amp section then I don't want to upgrade for many, many years. I am a dealer of Parasound audio. I guess that helps. The Parasound 5125 seemed like a great match at first but the 5250 is an amp that I most likely will not upgrade from.

Also, far more power. What I notice with my system is that at high listening levels, details become lost, the tonal balance shifts to harshness. The older and lower end Yamaha receivers have a reputation of being treble predominant, so I guess that doesn't help my cause either.

--Regards,

 

[Vaughan Odendaa]

I'm also well aware that acoustics plays a large role but I also think I'm considerably underpowered. My Parasound rep tells me that using two Parasound JC-1's (400 watt monoblocks) on a pair of the C803's made considerable differences.

Now unfortunately I can't afford that but the 5250 is the closest that I'm going to get and it is a brute of an amp. Concerning the acoustics, I'll probably just get some Ready acoustic bags and frames.

Heh.

--Regards,

 

[mazersteven]

I am a dealer of Parasound audio.

That would have been nice to know instead of me recommending Rotel, Emotiva, and Bryston.

You should put that in your signature or profile.

 

[Vaughan Odendaa]

Sorry, my job is almost secondary when I participate on forums such as this. I don't post here to recommend products to forum members. I participate to give advice in the fields that I specialize in and to get advice.

Sorry I never mentioned that I was a Parasound dealer. But even if I wasn't, I guess that I am not restricted to that brand only. In fact, a while back I even considered some of the high-end Outlaw models, but I don't think they ship to South Africa.

But as far as amps go, the Parasound range is what I consider to be the poor mans high end amp. Not quite Krell or Mark Levinson but not too far off either.

--Regards,

 

[mike c]

He said he wants to purchase the Onkyo 805.

yup, it's best he get the better onkyo first since the yamaha 450 is entry level and he might even notice a difference in SQ between it and the Oinky

I am a dealer of Parasound audio.

NC2125 or NC2250 or NC2250 PLUS bridged NC275 (then switch it two 4 ohms)

 

[mtrycrafts]

Well, the bulk of that power from an energy distribution point of view would be primarily "fed" to the woofer sections. If the low bass sections are high pass filtered and no longer require huge current draws then is there still reason to use huge power amplifiers ?

I have not used a big power amp (high pass filtered) then used on a pair of book shelf speakers so I can't really comment on the benefits. But for those that have (not necessarily restricted to just book shelf speakers), comments would be appreciated.

--Regards,

Yes, your low frequency driver, or sub is what needs the power. I have had a chance to see center channels in large mode, power amp with meters, peak hold types, and have yet to see them hitting in mid double digits without needing earplugs Subs on the other hand have been hitting in the low hundreds at the same time.

So, I would not worry about it. Remember that tweeters, most of them are rated in the low 2 digits, 20 watts or so before they start to fry.

 

[TLS Guy]

Yes, your low frequency driver, or sub is what needs the power. I have had a chance to see center channels in large mode, power amp with meters, peak hold types, and have yet to see them hitting in mid double digits without needing earplugs Subs on the other hand have been hitting in the low hundreds at the same time.

So, I would not worry about it. Remember that tweeters, most of them are rated in the low 2 digits, 20 watts or so before they start to fry.

Yes but tweeters crossover at 2.5 to 4 KHz usually. The 50/50 point of the power divide is still 400 Hz. The exception is during LFE during explosions etc, where there is a 20 db boost. I have been doing this a long time and there is lots of energy in the 80 Hz to 2.5 K Hz range, especially from 100 Hz to 1200 Hz.

 

[Vaughan Odendaa]

I'm not certain that my center speaker can handle very high SPL's when set to large on most demanding material. I'm sure that more power will be beneficial if I set the speakers to large but I'll run out of excursion too quickly at high levels.

Using the Onkyo 805 AV receiver will no doubt be a monumental step up in performance over the old Yamaha receiver. But the real question is, would the Parasound 5250 be a huge step up in my system over the Onkyo especially given the application that I'm using it for ?

I mean, the Parasound is in a completely different league as far as clean power goes. I'm just a bit apprehensive that in my specific configuration with speakers high passed, most of that power will not be put to use. Comments would be appreciated.

--Regards,

 

[TLS Guy]

I'm not certain that my center speaker can handle very high SPL's when set to large on most demanding material. I'm sure that more power will be beneficial if I set the speakers to large but I'll run out of excursion too quickly at high levels.

Using the Onkyo 805 AV receiver will no doubt be a monumental step up in performance over the old Yamaha receiver. But the real question is, would the Parasound 5250 be a huge step up in my system over the Onkyo especially given the application that I'm using it for ?

I mean, the Parasound is in a completely different league as far as clean power goes. I'm just a bit apprehensive that in my specific configuration with speakers high passed, most of that power will not be put to use. Comments would be appreciated.

--Regards,

It seems to me you have a desire for separate power amplifiers. Why don't you forget the receiver and get a preamp processor.

The Rotel line will not break the bank.

http://www.rotel.com/

Rotel re a B & W company. I have been very pleased with mine.

Anthem have a new line that is also reasonable.

http://www.anthemav.com/?gclid=CNjb_u-KxpACFRfbQAodyQ5FQA

Adcom also are in the cost effective range.

http://www.wildwestelectronics.net/pream.html

This is a much better way to go than receivers, I think. One of Parasound five channel amps should then fit the bill well.

 

[davidtwotrees]

TLS is wise and Speaks the Truth.

It seems to me you have a desire for separate power amplifiers. Why don't you forget the receiver and get a preamp processor....This is a much better way to go than receivers, I think.

Hey, I agree on this one. And Parasound makes an "affordable" line of seprerates........the 7100 controller prepro looks excellent....

Sighs. But I bet it's not "full featured" enough.

The Integra 9.8 has gotten rave reviews across the board....Stereophile just gushed about it this month......and it is so full featured you can launch the Space Shuttle from your H.T.! Smiles.......

The OP never said what his preferences were.....my HT has morphed into 95% music and 5% movies.......so video features are WAY down the list for me.

 

[davidtwotrees]

Oh, and I just read a thread talking about Emotiva's new prepro. The pasted a quote up from someone at Emotiva [big dan], who gave a detailed despcription of what the new unit wil do..........it was impressive and is due out early in 2008. Damn those Chinese.........