RE: equality of power to all 5 channels, big deal?

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

beethovenfan

Member
Joined
Jul 22, 2006
Messages
9
Reaction score
0
RE: equality of power to all 5 channels, big deal?

I am about to switch to 5-channel HT. Amp is Sunfire Cinema Grand (225x5). I want the main speakers (Request) to be biamped, with one channel left for the center, however, my concern is that it is essentially impossible for front, center and rear ones to be powered by amp(s) with same power rating. Will this be a problem? How important is it for all the speakers being powered up by amp(s) with same power rating? I have heard this is very important. I have an extra Carver stereo amp with 375wx2. In summery, I want best possible HT results with current equip without even the slightest compromise on pure 2-channel stereo listening. Any experience will be appreciated.
 

mrmike

Well-known member
Joined
Feb 15, 2006
Messages
86
Reaction score
0
It would depend mostly on the output of your amp to the woofers and panels of your mains. The extra watts to one or the other will probably need volume adjustment. Keep in mind that people lucky enough to have ML's with powered woofers don't match the amp to the panels and adjust the volume accordingly. The other three channels usualy can be adjusted.

I currently use an Adcom 200watt 3 ch amp for woofers and center and a matching Adcom 2 ch amp for panels. My surround speakers are easier to drive and the least critical to have a matching sound so I just use the avr to drive them.

You system will work if you can adjust woofer to panels or you could use the sunfire to drive the front 3 and have a balanced sound. Another consideration is what kind of center and surrounds you have.

Just a low tech guys point of view.
 

roberto

Well-known member
Joined
Jan 1, 2005
Messages
3,312
Reaction score
82
Location
San Jose, Costa Rica
beethovenfan said:
I am about to switch to 5-channel HT. Amp is Sunfire Cinema Grand (225x5). I want the main speakers (Request) to be biamped, with one channel left for the center, however, my concern is that it is essentially impossible for front, center and rear ones to be powered by amp(s) with same power rating. Will this be a problem? How important is it for all the speakers being powered up by amp(s) with same power rating? I have heard this is very important. I have an extra Carver stereo amp with 375wx2. In summery, I want best possible HT results with current equip without even the slightest compromise on pure 2-channel stereo listening. Any experience will be appreciated.
Hola chicos...I have a rule that might be good for you too...it is better quality than quantity. I rather have good watts than many so-so watts. Sunfire is another good SS power amp. Of course too, front and center are more important than rear, but if you use a component in the whole chain of the system, that it is not as good as the others, you will be listening it affecting the sound. Quality does not means expensive. You can use less power for the surround speakers with no problem. And also you can match their sensitivity, in case that they have it different, with the channel level adjustment. Hope this can help!...happy listening,
Roberto.
 

robertawillisjr

Well-known member
Joined
Jan 22, 2005
Messages
556
Reaction score
0
What is the real advantage of dynamically bi-amping the ReQuests. I have a pair of Quests and know 4 people (small sample i know) with either ReQuests and Quests. We have all tried dynamically bi-amping with very good amps and the benefit to bother ratio (and expense) wasn't enough for any of us to continue with the process. Unless you disable the internal crossover network and theusen an active external crossover network I wouldn't recommend it.

Since you have a Sunfire, you can always use the voltage outputs for the panels and the current outputs of the same channel for the woofer. That works well.

I also think the synergy of using the same amps (model and power rating) is very important. When my Levinson amp had to be repaired, I used my Sunfire for all channels and while the mains didn't sound as good, the overall blend was much better. However, most of my listening is 2 channel so the Levinson was promptly reinstalled after repair.
 

beethovenfan

Member
Joined
Jul 22, 2006
Messages
9
Reaction score
0
Thanks for the help. I am glad I have found this site. Currently I am using the ReQuest as stereo speakers. I have experimented it with bi-amping since it has separate posts for the woofer and panel (apparently, this is not the absolute or active bi-amping) but I feel I they sound cleaner. I am using separte Carver amps for left and right speakers. I use one TFM-45 for left speaker and another TFM-45 for right speaker and I have tried jusing one TFM-45 to power both speakers (of course, the jumper has to be on the speaker post), although one TFM-45 can effortlessly handle both, I just "feel" it does sound cleaner with slightly better clarity. I tried many times including using one amp to power panels on both sides and using another amp to power subwoofers on both sides (also feels better than just one amp but I can not tell the difference between "horizontal" bi-amping from vertical bi-amping), and now I just do not want to give up bi-amping on the said speakers as I believe it now. I played a lot of Piano (solos and concertos) and they did sound cleaner to my ears. I am new to Sunfire and HT. While it is exciting to have a HT, I do not want any compromise for the absolute pure two-channel listening while keeping the numbers of amps to minimum if possible since I am having the 5-channel Sunfire now. Thanks for telling me the individual volume of each speaker can be adjusted. One of you suggests using current and voltage of the output of the main speakers to power the panel and subwoofer individually. My quesition is, each channel is rated a max 225w, how is the power distributed between "current" and "voltage" source, are they still at 225w max individually? Is underpowring a concern here? I am stilling missing a couple of pieces and will experiment when all the gears are in place but I would like to hear your experience too. Thanks fellow ML fans.
 

wink

Well-known member
Joined
Jul 12, 2006
Messages
516
Reaction score
16
Location
Phoenix, Arizona
My experience has shown that using the same amp for all channels makes for the best tonal blend. If that isn't possible,then I would strive to use the same amp for at least the front three channels and different amps for the rears and side axis channels.

Just my .02

Dan
 

beethovenfan

Member
Joined
Jul 22, 2006
Messages
9
Reaction score
0
I am tempted to try the biamplification with an active crossover. The biamp is passive with ReQuest as it is difficult to bypass the internal crossover but my next experiment is using an active crossover with frequency set at 280 Hz to match that of the ReQuest's. I am not sure it this can be called true active biamping. I am willing to accept any of the following results: magic, better, same, worse or disaster. Anyone tried this approach? Any suggestion on choosing an active crossover? Thanks in advance.
 

JonFo

Super Moderator
Moderator
Joined
Jan 16, 2005
Messages
4,310
Reaction score
155
Location
Big Canoe, GA
beethovenfan said:
I am tempted to try the biamplification with an active crossover. The biamp is passive with ReQuest as it is difficult to bypass the internal crossover but my next experiment is using an active crossover with frequency set at 280 Hz to match that of the ReQuest's. I am not sure it this can be called true active biamping. I am willing to accept any of the following results: magic, better, same, worse or disaster. Anyone tried this approach? Any suggestion on choosing an active crossover? Thanks in advance.
I am a big fan of biamplification and Sunfires. My rig uses 13 channels worth of Sunfires ;)

For straight up biamping on your requests, put the 2ch Carver on the bass drivers and use the 5ch for the rest.

I do not recommend using active on top of the factory passive, this will just mess up the sound with huge dips around the crossover point. Also potential phase interactions will make it sound worse than stock.

Bypassing internal crossovers is not that hard, but does require some electrical skills (and some risk) to get them set up.
The woofer is a piece of cake to bypass, just wire straight from the binding posts to the speaker terminals, the high frequencies are trickier as you have to cut wires and bypass parts.
See my thread on the Center Channel effort for what it takes to bypass the crossovers.

Once you go active, there is no reason to go back to passives, ever. IMHO.
 

Spike

Well-known member
Joined
Jan 20, 2005
Messages
766
Reaction score
24
Location
SF Bay Area
Passively bi-amped reQuest

beethovenfan said:
I am tempted to try the biamplification with an active crossover. The biamp is passive with ReQuest as it is difficult to bypass the internal crossover but my next experiment is using an active crossover with frequency set at 280 Hz to match that of the ReQuest's. I am not sure it this can be called true active biamping. I am willing to accept any of the following results: magic, better, same, worse or disaster. Anyone tried this approach? Any suggestion on choosing an active crossover? Thanks in advance.
My reQuests are passively bi-amped with tubes on the panels and solid-state on the bass. The 200Hz crossover point (not 280 Hz as mentioned in your post) is just outside the critical midrange that I could live with passive crossover. Furthermore, the benefit of tubes on the panels more than outweight the theoretical ideals of active crossover. All in all, I'm very happy with the result.

Spike
 
Top