Maybe you could explain your system and setup.
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Thanks for the suggestion Bob reynolds. I have moved the wiring so that one channel of each amp runs the top end while the other channel runs the bottom. Sounds good but I still have the mid/hi channels turned down about 2 clicks.I will do some more testing and will read up on the active crowwover info.
Sounds good but I still have the mid/hi channels turned down about 2 clicks.
How are you able to control the level for a single channel? Do your NAD amps have input attenuators for each channel? If so, then get out the voltage meter and play a test tone (I can send you one) to check the voltages at the speaker binding posts.
In theory there is much to be gained by using active crossovers, but in practice you'll likely never be able to correctly replace the passive crossovers in your speakers unless you're a speaker designer and have the appropriate test equipment.
Dear Blueskiespbd: In what may seem to be an attempt to toss the cat among the pigeons, I can assure you that this question may seem a moot point, but I some of us are anxious to hear the answer. Did you physically remove the passive crossover in your speaker cabinets or did you leave them in and simply bypass the parts?
the amps do have volume controls for each channel. I am currently doing some testing tonight with the Rives cd and my SPL meter to replot the curve from my original baseline since I have moved the speakers and made some other tweaks. What frequency shoud I use for the test you are thinking of?
The current crossovers are untouched. The snells I believe us woffers in parallel so I do not know if active crossovers would make much of a difference?
My experience is that passive biamping does produce an improvement, but it is not huge relative to the cost of buying another amp. This is because you are still using the speaker's crossover. However, if you already have two amps, then it would be worthwhile to give it a try since your speakers have two sets of binding posts. Where you get a huge improvement, however, is when you go to active biamping. But this requires the addition of an electronic crossover and the removal of the speaker's crossover. Stripped of the technical lingo, the improvement is due to the better control of the drivers and the precise separation of the frequencies going to the drivers. The problem is that the speaker designer designed the speaker as an integrated package: cabinet, drivers, crossover, etc. If the speaker wasn't designed to upgraded to active operation, you could get unpredictable results by replacing the designer's crossover with another one. For this reason, I would suggest that if a person were to do this, the crossover they add should try to match the crossover frequency and slope of the original crossover in the speaker.
The poster above who says that you are not biamping does not appear to understand the difference between passive and active biamping. Apparently he has some other issues too that he needs to work out.
I can't easily explain what you are finding if you have two identical amps that are working properly. You have no difference when vertically biamping so this tells me that the amps are probably fine. But the difference does emerge when you horizontally biamp. Because of this, I'm inclined to think that there is something going on in the speaker's crossover. Perhaps these speakers aren't meant to be biamped because of whatever is going on in the crossover. The double binding posts may be for bi-wiring, but not necessarily bi-amping, though that seems a bit odd. I don't know. Perhaps you might want to contact Snell to see what they have to say about having their speaker's biamped. You also might try reposting a thread with a title containing something like: "Bi-Amping Snell speakers". This might attract some posts specifically from other Snell owners who have done this.
My experience is that passive biamping does produce an improvement, but it is not huge relative to the cost of buying another amp.I've had similar experience. I've tried many amp combinations on 2 separate systems and found one case where biamping produced improvements over one amp material enough (to my ears) to keep it running in biamp mode. This is running vertical biamp configuration driving Von Schweikert VR4-III's. I also tried this with Totem Mani-2's. In both cases I asked the speaker mfg if I would be better off using biamping vs one larger amp I was trying to decide if I should buy a larger monoblock Eagle 11 vs using my Eagle 4 amps. Totem said one large monoblock would be best (which I confirmed). Albert Von Schweikert said vertical biamping would be better. The VR4's are 2 separate modules and he recommends passive biamping. I've tried many other amps and none have performed better than the Eagle 4s in vertical passive biamp.
It will be interesting and worthwhile to hear what Snell recommends . . . but I suspect you may have proven the point already.
Blueskies, to measure the voltage at the speaker binding posts and verify that the amps are operating correctly, I've used a 1KHz sine wave at -20dBFS. I play some music to set a comfortable volume and then play the tone continuously at that same volume setting. With the input attenuators set at unity gain, the voltages should be very close -- within a fraction of a dB.
Old thread, but I'm a new AudiogoN member.
My primary speakers are Snell Type D's. I own two Nikko Alpha 220 amps, which are 120wpc, similar wattage to Blueskiespbd's NAD 2700's. I have biamped the D's with one amp powering the bass and one the highs. I did not experience any loudness variation between the bass and highs, as compared to just one amp. The sound was quite similar to using just one of the amps, but the bass was somewhat tighter and the overall sound was indeed slightly better.
Bottom line, biamping should work.
I must say that the Snells perform so well with one amp, that I'm not sure the second is worth the effort and right now I'm only using one.
Either way, even with the Snell D's, the soundstage, vocals and bass are incredible. Every time I sit back and do some serious listening my eyes are deceived because the singer is not in the room.