ICE amps vs analog amps for bass


I'm currently running Legacy Helix loudspeakers. The bass and subwoofers are being driven by two pair of 500 watt ICE amplifier modules while the Midrange and treble frequencies are being driven by two pair of Levinson 436 amplifiers. While originally auditioning the speakers I heard them with analog amps on the bass, treble, and midrange sections and the sound was superb. However, I was assured that the ICE amps would be sufficient to drive the bass sections so I've given them a try. However the bass sounds funny. I don't hear the impact, definition, and subtle "spatial cues" that I know are in the recordings.
I partially am blaming the ICE modules. I'd sure like some input in solving the problem. I can "upgrade" to "analog" amps for the bass if I choose, but for space reasons and economic reasons, would prefer to continue to use the ICE amps. I'm considering Parasound JC-1s, or Bryston 7bs, for the bass if I switch.
Thanks for your help in advance.
Steve
128x128sgr
I have painstakenly moved them through the listening area. Bill Duddleston,the designer and owner of Legacy Audio, set the speakers up himself. The Xylex crossover is unique in that all parameters of the speaker can be adjusted through the crossovers software on your laptop. He adjusted the speaker so that it each driver was time aligned and zeroed in the speaker.
However, I recently reversed the polarity of the right speaker, and things immediately jelled. Bill and I are both puzzled about the results and are investigating further.
Yet even though the speaker is overall clearly superior to my Revel Salon/JL Audio combo, there are still nuances that I miss when I listen to familiar recordings. They don't sound bad, I just know there is something missing, and it is in the bass/sub bass area. This appears hard to convey to the designer.
This is why I suspect the ICE Power amps. The bass does jump out at one, and is impressive, I just don't hear the bloom and subtle shadings I was used to.

Anyway thanks for all the suggestions. I will try positioning the speakers some more. I've seen this make a great difference.
I'd sure welcome other opinions, I'm sure there is something I'm not considering.

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Thanks,
Steve
Steve, ICepower is a technology with great potential. . . and with that go a lot of dangers. The problem is that while ICEpower ASP modules can be used to designed some very remarkable high end amps with bass texturing to die for, like the Bel Cantos already discussed and like the Roland Continuum 512 and the Rowland 312, they can also be used -- essentially by themselves -- to implement some absolutely bare bone devices, which sound like, well. . . what you are hearing from your bass drivers.
Thanks Guido,
This is what I'm suspecting!
If they were modified in some way besides just the modules themselves I think they could sound great.
Steve
Another issue to consider is the impedance match between the preamp and amp. The Icepower module should have an input impedance around 8Kohm. Many preamps need to see a higher impedance at the amp for best sound. Some Icepower amp builders use techiques to raise the amps input impendance and others do not.
Damping factor... I can also agree with the fact impedance matching can cause some havoc.

Interestingly everyone raves about High damping factor 1000, 2000 etc... But you can take a class A amp like a tube or solid state that has no more than 200 damping factor and 50 watts blows away the bass tone on Class D based amps.

Seems sometimes the super high damping amps choke the life out of the full flowing tone a good A-B or Class A amp is capable of... Most like to use the term "Tighter" bass from high power high damping amps, but in my experience its so tight you barely feel or hear it sometimes! So there are several factors to what will work with each speaker design and amp combo, there is no perfect all in one solution.

Mostly Class D is used in cheaper subwoofers because Ice modules are cheap, efficient with high power, high reliability, high damping, and run cool while beating the hell out of them. But they still do not have the tone of good "Analog" designs as you put it. However Class D does not stand for Digital, they are still analog chips from my understanding.

By the way the Legacy speakers tend to use PRO audio type drivers, and those big bass drivers on the Helix is probably made by JBL or Eminence etc... And are low excursion big coils, and very tight physically from movement. Get a lower damping amp, costs more for a good one like a Mcintosh or something and kinda a waste on bass only, but it works and brings back that full tone getting rid of the steril Class D sound. I highly suggest going local and borrowing a good old standard amp and see your results, then you will have the information you need moving forward to eliminate the Ice amps or not.

I have gone thru very similar trials, and found better big old fashioned hot running amps will give you the natural feel and tone your missing with Class D.

High damping factor vs. High musicality is highly overrated in my opinion!