Downside of sealed cabinets?

The Pass XA.5 series is definitely at maximum power at 4 ohms. The XA.8 series is more powerful at lower impedances, but doesn't have that 6 dB of Class A/B headroom, maybe only 1 dB or even less. So there may be something going on there. OTOH I can't imagine Myles' CJ's having much output at 2 ohms either, so it might be something else.
 
You guys have better ears than I do. I haven't noticed any bass drop-off with the S5s, and believe me, I used to play them loud. Then again, at loud levels I mostly play classic rock, which doesn't have the kind of bass found, for example, on Lady Gaga's first two CDs (Fame and Fame Monster). I have to turn it down when those songs play since it pounds. The Pass X600.5 meters bounce all over the right side for her.
 
mep said:
That's why I said all amps are not created equal with regards to how much power they can put out into a given load. Sometimes phase angles cause issues with amps as well.
Click to expand...

True, but if the XA160.8 is anything like that XA60.5 I linked above, it should be an absolute beast...and have no issues driving the S5s to very high levels (though not too high, unless you want a tour of the factory! :P )

cheers,

AJ
 
rbbert said:
The Pass XA.5 series is definitely at maximum power at 4 ohms.
Click to expand...
The one Stereophile tested above had no issues into 2 ohms. In fact, it quadrupled its output (400+ watts), which is textbook and an indication of a superbly robust design.

cheers,

AJ
 
Thanks for all the responses, guys, I really appreciate it.

I thought I was on to something - i.e. an explanation for what I think I'm experiencing, but it seems it wasn't that simple.

I don't think my amps are having any trouble driving the S5's. The needles really don't budge (my understanding is that if they were taxed in any way, the needle would start dancing). It might just be that my room is slightly too big for the S5's (not sure)./

I am regularly playing around with speaker positioning, trying to find that balance where the bass remains articulate vs too much bloom. I am hoping to audition some other amps in case there is a more magical combo than what I am enjoying now. Hegel was high on my list until I read that it was on the lean side. Constellation will probably be what I try first as it's supposedly a great combo.

Loving the speakers. Never heard such clean reproduction of vocals, woodwinds etc, but sometimes I do miss the power of the Alexias. Speaking of which, I've never put them back in the system since getting the S5's (they're up for sale). I just might do that someday soon - partly to enjoy the 'power' that they convey so well when I crank the volume, partly to see how I react to what I think it's imperfections are.
 
BlueFox said:
You guys have better ears than I do. I haven't noticed any bass drop-off with the S5s, and believe me, I used to play them loud. Then again, at loud levels I mostly play classic rock, which doesn't have the kind of bass found, for example, on Lady Gaga's first two CDs (Fame and Fame Monster). I have to turn it down when those songs play since it pounds. The Pass X600.5 meters bounce all over the right side for her.
Click to expand...

Hey Bud, I play a lot of classic rock as well. I'm not talking a lack of *deep* bass per se, but just overall bass volume compared to higher frequencies. I happen to love Supertramp and 'School' has a great instrumental section that really sounds great on the S5's - articulate bass, clean highs etc., but when I turn it up the bass doesn't 'appear' to get much louder whereas the highs do - and start dominating, making it seem like the tonal balance has changed.

Anyhow, just wanted to point out that it wasn't deep electronica-style bass that I was speaking of.
 
madfloyd said:
I don't think my amps are having any trouble driving the S5's.
Click to expand...
Me neither quite honestly.

madfloyd said:
I am regularly playing around with speaker positioning, trying to find that balance where the bass remains articulate vs too much bloom.
Click to expand...
If the latter part is true, then I think we have our answer. If there is a position where the bass is too thick, then it certainly isn't an amp issue, but rather, as I suspected, a room/speaker issue....which is always the biggest one of them all.
My guess is that where they sounded a bit fuller in the bass, is also where they didn't image as well. Now you have them imaging nice...but the bass is light. Front wall proximity.
Audiophiles must be somewhat masochistic. A simple shelving filter, like a good 'ol "Bass" control would probably fix that, but those went the way of the Dodo in "High End" preamps what, around the 80s or so? I imagine now they would be absolute heresy.
I highly doubt any "amp rolling" will fix that, unless it functions as an EQ as well.

cheers,

AJ
 
madfloyd said:
Hey Bud, I play a lot of classic rock as well. I'm not talking a lack of *deep* bass per se, but just overall bass volume compared to higher frequencies.
Click to expand...

I am taking Friday off, so I will do an experiment Thursday night, and see if notice that.
 
madfloyd said:
Thanks for all the responses, guys, I really appreciate it.

I thought I was on to something - i.e. an explanation for what I think I'm experiencing, but it seems it wasn't that simple.

I don't think my amps are having any trouble driving the S5's. The needles really don't budge (my understanding is that if they were taxed in any way, the needle would start dancing). It might just be that my room is slightly too big for the S5's (not sure)./

I am regularly playing around with speaker positioning, trying to find that balance where the bass remains articulate vs too much bloom. I am hoping to audition some other amps in case there is a more magical combo than what I am enjoying now. Hegel was high on my list until I read that it was on the lean side. Constellation will probably be what I try first as it's supposedly a great combo.

Loving the speakers. Never heard such clean reproduction of vocals, woodwinds etc, but sometimes I do miss the power of the Alexias. Speaking of which, I've never put them back in the system since getting the S5's (they're up for sale). I just might do that someday soon - partly to enjoy the 'power' that they convey so well when I crank the volume, partly to see how I react to what I think it's imperfections are.
Click to expand...

Ian:

Did you try taking all the power line conditioning stuff out? And then the PCs?
 
AJ Soundfield said:
And of course a Stereophile test of a more recent Pass XA (.5 series), shows much better output vs decreasing load (more along the lines of what I would have expected to see):
Pass Labs XA60.5 monoblock power amplifier Measurements | Stereophile.com

....so I'm back to thinking it's speaker/room issue. Some positioning experimentation might be prudent.

cheers,

AJ
Click to expand...

The .5s are MUCH MUCH better at handling demanding loads due to low impedance. Another words a non issue!
 
Myles B. Astor said:
Ian:

Did you try taking all the power line conditioning stuff out? And then the PCs?
Click to expand...

Funny you mention that, Myles. Just before acquiring the S5's I switched to MIT cables (from Transparent). Where the Transparent seemed to focus on midrange, the MIT excelled in deep bass and extended highs, somewhat thinning out the midbass (which worked well with the abundant midbass produced by the Alexias in my room).

I had also added Shunyata PCs, a Triton and two Typhons. The Typhons also 'focus' the bass, making it much more articulate but leaner. Removing the Typhons seems to fatten up the sound, but change the timbre for the worse (although it may just require some getting used to - jury is still out on that). In any event, I'm starting to play around with that a bit.

Myles, has it been your experience that power line conditioning thins out the bass somewhat?
 
The XA160.5 and the X600.5 are basically the same amp, just biased differently. It's possible that independent testing shows the XA160.5 still doubling power into 2 ohms, but it won't be much Class A; as I posted earlier, the maximum Class A output is at 4 ohms, 320 watts. Either way, it seems unlikely to be an amp issue.
 
madfloyd said:
Funny you mention that, Myles. Just before acquiring the S5's I switched to MIT cables (from Transparent). Where the Transparent seemed to focus on midrange, the MIT excelled in deep bass and extended highs, somewhat thinning out the midbass (which worked well with the abundant midbass produced by the Alexias in my room).

I had also added Shunyata PCs, a Triton and two Typhons. The Typhons also 'focus' the bass, making it much more articulate but leaner. Removing the Typhons seems to fatten up the sound, but change the timbre for the worse (although it may just require some getting used to - jury is still out on that). In any event, I'm starting to play around with that a bit.

Myles, has it been your experience that power line conditioning thins out the bass somewhat?
Click to expand...

I agree with you observation of the MIT vs. Transparent. Are you using MIT throughout? I found that the IC and speaker cable are synergistic. For instance, when I used the Oracle IC/phono with the Transparent speaker cable, the system sounded wonderful except for a small region in the midrange that was slightly dynamically lacking. Hooked up the MIT speaker cable and it seemed to compensate for that slight aberration observed with the ICs.

Vis a vis PLC. It certainly could. I've heard lots of weird stuff happen over the years.

It's just my experience that when things are getting constricted with big wattage amplifiers (combined and with might be thinness/brightness) to look at power cords and PLCs. Some PCs/PLCs sound fine with low powered amplifiers and not so good with bigger amplifiers. Same goes when you talk about demanding speakers like the S5.
 
Myles B. Astor said:
I agree with you observation of the MIT vs. Transparent. Are you using MIT throughout? I found that the IC and speaker cable are synergistic. For instance, when I used the Oracle IC/phono with the Transparent speaker cable, the system sounded wonderful except for a small region in the midrange that was slightly dynamically lacking. Hooked up the MIT speaker cable and it seemed to compensate for that slight aberration observed with the ICs.

Vis a vis PLC. It certainly could. I've heard lots of weird stuff happen over the years.

It's just my experience that when things are getting constricted with big wattage amplifiers (combined and with might be thinness/brightness) to look at power cords and PLCs. Some PCs/PLCs sound fine with low powered amplifiers and not so good with bigger amplifiers. Same goes when you talk about demanding speakers like the S5.
Click to expand...

My SC's and IC's between the phono preamp and preamp are MIT. I have a 25ft run of Transparent (single ended unfortunately) between my preamp and amps (left over from my Doshi setup) which I haven't replaced. Unfortunately my phono cable is non-removable and I have no idea what quality it is (Triplanar arm).

Caelin Gabriel of Shunyata did mention to me that he was slightly worried that I have might have some restriction of current (forget the term Shunyata uses for this) because I have some Equi-tech transformers between my main electrical box and the amp outlets - where the transformer *could* be too small. He suggested having an electrician bypass the transformer as an experiment. Perhaps that might be worth doing.
 
madfloyd said:
My SC's and IC's between the phono preamp and preamp are MIT. I have a 25ft run of Transparent (single ended unfortunately) between my preamp and amps (left over from my Doshi setup) which I haven't replaced. Unfortunately my phono cable is non-removable and I have no idea what quality it is (Triplanar arm).

Caelin Gabriel of Shunyata did mention to me that he was slightly worried that I have might have some restriction of current (forget the term Shunyata uses for this) because I have some Equi-tech transformers between my main electrical box and the amp outlets - where the transformer *could* be too small. He suggested having an electrician bypass the transformer as an experiment. Perhaps that might be worth doing.
Click to expand...

Be an interesting experiment if not too expensive. Just sounds to me that you're getting some current limiting somewhere. But what do I know? :) Mongo just pawn in game of life.
 
madfloyd said:
I have some Equi-tech transformers between my main electrical box and the amp outlets - where the transformer *could* be too small. He suggested having an electrician bypass the transformer as an experiment. Perhaps that might be worth doing.
Click to expand...
If there was some sort of "limiting" taking place electrically, it should be irrespective of speaker position (within reason).
i.e., if the speakers are placed closer to the wall where the bass is a bit too full, by cranking it up a bit, the bass should "lean out". This would be a simple experiment to do.
If it has nothing to do with current or other limiting, the bass should remain a bit too ripe, just louder.

cheers,

AJ

p.s. sorry about calling you "Floyd" earlier, I guess it's Ian :)
 
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