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, what ICEpower based amps are you using? If you are using bare modules, which ICE modules? What is the sensitivity and impedance of your speakers bass section?

The other issue is that ICEpower amps take a long time to break in. . . before about 500 hours of break in they sound rather dry in the bass. They also take long to warm up. . . when powered up, once again, they sound dry. . . you can leave them on 24/7 with minimum use of AC.
Icepower 500 ASP I believe two per speaker. I'll have to check further with Legacy. Also the impedence is 4 ohms and I don't know the sensitivity although the speakers are very efficient at over 98db. Please go to the Legacy Audio site and read about the speakers. The amps are directly plugged into the wall, and I assume always on, as they play as soon as I send a signal to them from the preamp.
Steve, how many hours have you played music on those speakers? Can I assume the bass amps are the Legacy PowerBlocks?
I don't believe they are the Powerblocks. They appear to be unmodified ICE Power Modules. Yes they have played more than 500 houes as I've had them sinse May.
my response would probably fall under the category of "covering all the bases" and you've probably already thought about it, but i would just make sure your cables are up to the job. seems like they sould sound good with decent power, interconnect, and speaker cables.

my martin logan summits (which i believe use ice modules in them to power the woofers) react quite differently to which interconnect (and power cable) is used for the bass frequencies - and to a lesser extent, speaker wire.

quite a few interconnects i've tried with them make them sound slower and woolier (i feed the panels and the woofers separately). i've had very good luck with silver interconnects on the bass, you could try a mac ultra silver, for example, for a ridiculously low cost.

good luck
Parasound JC-1's for the bass would be like drinking a top-shelf Burgundy with a taco - they're better than your Levinson monoblocks and would sound superb full-range on your Legacy's.

You may not have an A/C power supply that's sympathetic to Class D amplification. If you could get a hold of a power supply for the ICe modules, like Rowland's power supply, you would get a lot more performance.

That said, I again suggest running your Legacy's full-range with JC-1's, or even better, going with a much lower wattage amp like Pass's XA series or the darTZeel. A 98 db. efficient speaker gives you the luxury of avoiding high-powered amps, which require feedback to stabilize the circuit and have too many output devices to provide natural sound.
Maybe you need to try a different brand. You know even analog amps sound quite different from brand-to-brand. I have a class A/B amp on my main system and tried many As and A/Bs on both it and my second system. I just bought a Bel Canto (Class D) amp for my second system and the bass is very good. Also it didn't take long to break in and doesn't need to be left on all the time, although I think idle power draw is only 17 watts so it wouldn't matter much in that regard. I turn it off because I prefer the blue power diode off at night in my bedroom although it's not bad (not like the Pass backlight that lit up the whole room). It sounds great right on power up. I suggest you consider a different amp. Especially for bass only, you shouldn't need to worry about any of the criticisms on Class D. In fact Class D amps are almost universally regarded for their bass performance.
Within the Bel Canto line, I suggest the Reference 500 monoblpocks. . . they use the same ICEpower 500ASP that you have deployed, but John Sytronczer has built around them an amplifier that is incredibly musical. I have evaluated their bigger broter, the REF 1000 Mk.2 for Positive Feedback, and the bass is very delightful. G.
One caveat on the ref500s. Although they are supposed to be the best sounding amp Bel Canto makes per John, according to my dealer he hasn't sold any. Why? Because the Ref1000s are only about $500 more so customers either buy the ref1000s or drop way down in the price range to the s500 (almost half the price of a pair of ref500s). Or they drop down to the ref1000s Mk1s at 2/3s of the price of the MkIIs. I've read that the Is sound pretty close to the mkIIs. Just something to consider if you plan to sell at some point.
Thanks for all the suggestions. The Legacy Helix cannot be run full range. They are designed to be quad amped with a stereo amp for the treble, a stereo amp for the midrange, a stereo amp for the bass, and a stereo amp for the subs. The setup from Legacy included ICE amps for the subs, ICE amps for the bass drivers which are built inside the speakers cabinet. My Levinson monos are arranged as follows one pair for the midrange, one pair for the treble drivers. I've chosen to use monoblocks (which I owned already) so that each speaker sees about 1,750 watts per channel. This is truly a remarkable and innovative setup. Please read the Dagogo review on the Helix speakers.

Again I'm glad for all your help and suggestions.
Oh, I'm using silver interconnects from Signal Cable from all the crossover connections to the speakers.

i had two dig. amps,Bass was extremely powerful and pretty detailed,but when it got right down to it it was just way to much,all anybody hears about is the high damping factor,,blah blah blah.Now i have a Counterpoint amp,do i at times want a bit more bass sure i do.What i found is bass and quality of it is way way more dependent on the RECORDING if its strong on the recording,its more then good enough on my system,I think my damping factor is 75.
With 98db sensitivity and over a kilowatt per side, I'd say power was not your problem.
Setup? Are these speakers a new-2-you install? Have you tried some room mods? Are they located optimally?
The 'd' amps may simply pass the signal more quickly or slowly than the amps it is paired with. Sound travels about 14" per milisecond, so it won't take much time differrence to 'smear' the image. Phase/timing issues will destroy many of the phase/ spatial q's which you complain about. Likewise, cables should be the near-last thing to worry about.
Sounds like your speakers could also be out of *relative* phase, at least in the sub module.....? hmmmm
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.

Againg if you're not familiar with this SOTA contender,
check out the DAGOGO.

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.
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!
Some amps I'm considering are the Brston 7B monos or the 14b stereo version with a damping factor of 300 at 20 hz or the Parasound JC-1s. The JC-1s have an over the top damping factor 1200 at 20hz. Any ideas wich ones might match up with my Levinson amps?
300 damping is excellent, you will fill the room with real tone and move some air for sure vs. what you have I believe.
As Guidocorona has already mentioned, it ultimately depends on how well it is implemented. I have a very special pair of Audio Magic Model 250 ICE-based amps and will NEVER let them go. Are they the "be all, end all" of I'm 100% sure that the budget it would take for me to replace them with something better is WAY out of my league.
There we go with damping factor again.
Thanks again for all suggestions.

Coofeey, Thanks for reminding me about the damping factor thing again. I believe you'd be right.

Vman71, The ICE power, I've no doubt would be just the thing, however the ICE power amps installed in the speakers are not modified in any way, just raw as B&O designed them.

So I'll be looking at Bryston 7b monoss or a 14b stereo. Would I need to get the latest spec to use as bass amps? As I have space limitations, maybe I should look at 14b ssts. Has anyone compared the newest version to the older sst series? Can older amps be updated by Bryston?
Thanks again for all your input.
hi Steve
i have used the 14bsst on my dual Volt 12" and dual CSS 15" and will say if you are using for bass only,go wiyh a older pair of 7bst(98-01) only..the sst only improved on the mid,slightly,so save the money .
i have also recently purchased a ML (333) for my mid/hi
No problem,i mean my amp is like 75 and as i said if its on the recording that's how it comes out,it depends on the recording.So also what im saying is i wonder if the bass from ice amps is really realistic or not,or are people just wowed by the big bad wham of these ice amps.It never impressed me.
Coffeey, I tend to agree with you. . . except that I hear badly reproduced bass on a great many amps, regardless of underlying technology. . . Very good bass is reproduced by very few amps, and some of these excellent bass reproducers happen to be ICEpower amps.
Sgr, if your speakers are 98 db, its very likely that they will not play very good bass using an amplifier with a high damping factor.

The reason is that a high damping factor is synonymous with amplifiers that can double the power as impedance is cut in half. That works for some speakers, but not very often for speakers with high efficiency. Such speakers are often expecting that the amp will make the **same** power, regardless of impedance! for more information see:

If I were you I would get an amplifier that you can run full-range- IME/IMO bi-amplified systems never work as well as full-range, provided the speaker is designed to be able to operate either way.
The speakers are designed and can only be played quad amped which is pretty unique and exciting. Legacy speakers are always built with efficiency in mind, but in my experience, have sounded better with wattage doubling amps like Krell. The Helix is usually sold with 1 pair of ICE amps to control the subwoofers. The owner then supplies 3 pair of stereo amps for the midbass, midrange, and treble.
I chose to use an additional pair of ICEamps for the midbass drivers, and it seems this has been a mistake. The ICE amp modules in question, seem to play the bass as one note, it is there, it is full of impact and dynamics but small nuances that I know the recordings I've used to adjust my new Helixes to the room are vague or missing. I've been working with Legacy to solve the problem and we have made various adjustments through the Xilica 480 digital crossover/processor,but I believe that I need to add separate pair of external amps for the midbass.

I heard and auditioned the Helix with 3 pair of stereo amps plus the ICE amps on the subs and the sound was to die for. In trying to hold down the expense at the time, Legacy suggested going with a second pair of ICE amps for the midbass. It sounded good at the time if it worked, but I'm afraid I'll need to get a 3rd set of monoblocks for the mid bass and see if it solves the problem I'm hearing.

All the answers everyone has given me have helped to confirm what my next step is in the search for the sound I know these speakers are capable of.
Thanks for all your continued help and suggestions.

I'm listening and learning.

Thanks again,
My Counterpoint doubles from 100 watts 8 ohms to 200 watts 4 ohms,by coincidence i have Legacy studio monitors and yes they are efficient,like i said earlier,while i am satisfied with the bass it really could be a bit more defined ,louder whatever you want to call it,so with my scenario could my set up be on the order of what Atmas spere wrote about?
The Legacy Studio monitors are Voltage Paradigm devices. So if you are looking for better bass on them, I would look into placement that allows you to take advantage of corners in the room, shorten the speaker cables if you can, stuff like that.
Thanks and when writing before i think you were referring more to the high damping of the ice amps if i'm correct.Also am i correct in that a lot of people think they can get more out of the recording then there really is on it in the first place?
Hi Coffeey,
Thanks the info I'm not hearing is on the recording as I've heard it on my previous system and others. I know the Helix should be able to provide this definition also. I heard it at Legacy headquarters, but have not been able to find these missins notes at home. That is why I'm questioning the ICE amps built into the speakers and am considering switching out the ICE amps for the midbass and using a more normal amplifier design like the Bryston or Parasound.
Just to clarify, have you hard other amps at home with your speakers that you liked better? Or are you basing this from hearing the speakers at another location in another system?

If the latter is the case, room/setup will make 1000% more difference than amps IMHO, assuming no major electrical mismatches