Tri-amping speakers - Which amps

Jerry mentions the 'flat response' being the speaker designer's intention (in some cases). Doesn't flat depend largely on environment. As I understand it, ideally you test a speaker outside to determine how it truly measures. Tri-amping with an outboard active crossover is the recommendation of the designer of the speakers I am considering. He has several designs of 2 way monitors (with passive crossovers) that he can match with his own designed passive sub(s). The builder has indicated to me that for the 'best' sound from his design you need to leave out the passive crossover from the monitor and go the active tri-amp route. You take measurements of the speakers output in your listening room using a Radio Shack meter and aided by pc software use the controls on the crossover to 'tailor' the sound to correct any problems with the room.
While this would take some work and time, it does seem to me to be the best way to get the most out of your equipment. This route would add some expense such as an active crossover, more cables, and more channels of amplification, but if done correctly would appear to have a lot of benefit. Yes, I know I said "if done correctly". It is common now for the more expensive subs, and some of the cheaper ones, to have a built in amp & equalizer to correct for any bass nodes in the room. Bass problems are supposed to be the most common and problematic but why not address problems at higher frequencies as well? Some speaker mfg put controls on the back of their speakers for basic adjustment particularly for the tweeter. Is this merely for personal taste or are they helping to taylor the sound to the particular room?

What speakers or drivers are you using?

BESL. Link below.
http://www.bamberglab.com/index.shtml

Cnut, the "flat" I was referring to is equal output from the speaker system over the entire frequency range with a given constant input.

Raw drivers will output more sound at some frequencies than at others. In many high quality speaker systems, the manufacturer has designed the passive networks to compensate for these non-linearities.

Now, there may be little of this in your speakers. Your internal networks may be nothing more than simple frequency separation and in that case, the active xover will give you far more control over the resulting sound and no degradation.

Cnut, you are correct that room dynamics can significantly impact frequency performance. Those controls for tweeters are there to compensate for rooms either full of sound absorbing materials or with many hard reflective surfaces. Active operation, however, will do a better job that those controls. You simply get much more control.

Since the manufacturer of your speakers suggests going active, that-s probably the way to go. My comments were really about folks who were contemplating going active on speaker systems where the manufacturer does NOT recommend active operation.

Lastly, I-d suggest the simple way to solve your problem is to purchase the two way monitors and then get a high quality powered sub. The high quality powered sub, by the way is active! Your active xover will supply the line level signal for the sub and then it will supply the line level for the mid-range and tweeters.

Cnut, if you go this way you only need a two way active xover and two stereo amps. Life just becomes so much easier/simplier.

Here is an example of a two way active xover:

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=245-862

There are more expensive units to be sure, but many folks have reported successful results with these.

Hope this helps -

Jerry

Hi guys,

I just came onto this thread and find it excellent. I am also considering a tri-amp set-up with an open baffle dipole speaker system using a DSP to provide x-over, eq. and in-room correction. As i understand it from the manufacturer, i have great flexibility in the amplifier and cable selection and set up for the system. As the DSP can adjust gains for differences in amplifier input impedances, one can use different amps and by re-adjustment, change amps in the future if one wishes. I have listened to a prototype of this speakers in a non-treated room and the sound was impressive using mid-fi amplification and cabling. The one drawback, in theory, that i see is that, all inputs into the DSP is digitized so that this may not work for those that need their all analog domain intact eg. vinyl. Also, one is limited to the quality of the digital conversion of the input signal in the DSP and this may also add and additional A to D and D to A conversion depending on whether the digital front end source is inputted directly or analog converted prior to the DSP. But, at the proverbial end-of-the-day, what really counts is the sound coming out of the speakers in your room and to your ears and the rest is just that... theory.

Rafael