Airtight/Usher Problem

[DaveF]

Gentlemen,

Hoping that some of you will have some thoughts or solutions on a problem I'm having ever since I got the Airtight ATM2. I'm having an issue where on certain recordings I'm getting a lot of 'brightness' or what feels like to me could be more described as a tweeter resonance. It generally happens on instruments such as woodwinds, flutes and even soft choral music! It doesnt sound valvey at all which doesnt make any sense to me at all. Even after a short listening session, my ears are feeling a bit tired or even aggitated. This is not obviously good! Now, dont get me wrong, the Airtight has brought major improvements to other aspects of the sound which Im delighted with but over the course of the last 2 weeks the problem described above is now an issue for me.

I borrowed a few interconnects 2 weeks ago to see if that would cure it. Now I'm sort of a cable skeptic but Im open minded enough to give things a try. These IC's where Music Strada and VenDen Hul First Ultimates and these certainly have never been described as bright so I had high hopes for them. The outcome: well they didnt really make any difference whatsoever which was dissappointing. Note, that I'm using Nordost Flatline speaker cable which is all copper and I'm told that this cable takes nothing away or adds nothing to the signal from the amp. It's the one cable change that I havent made yet but given the tiny differences(if at all) between speaker cables I dont think this is the root of the problem.

I then had a thought that perhaps the speakers were interacting with the room in some odd fashion. So in the last few days I've totally rearranged the room hoping that it would tell me something. Well improvements came from this, but I STILL have the same 'tweeter resonance' issue on certain recordings, usually ones with high pitched instruments an even chora musicl! When I put my ear down near the tweeter about a foot or two away I can hear this effect.
So the conclusion is that the problem is coming from the speaker and its NOT being generated by the room. Given the trials with the interconnects above, the problem is now obviously coming from the interaction between the Airtight and the Ushers only. I'm not sure why, I would have expected the Airtight to have a more rounded sound than the Gamut did even if the Airtight is considered a lean amp by valve amp standards. But I'm not really getting this. Perhaps the Ushers crossover is presenting the Airtight with an odd load that's causing this. Im not really sure. Valves have weird harmonics going on.......perhaps the Ushers dont like it or else Im sensitive to this aspect of valves?? Never experienced it with any other valves though.

I got the Airtight cos of the price it was going for and they rarely come up second hand plus my plan is to get the Kharmas at some point as I believe that they are the natural partner for the Airtight. (I feckin hope so!)

Anyway, I'll probably change the room back as it's not the issue anymore. I'll play around with a few other tweaks etc but deep down I know that the Kharmas are probably the solution and that there is probably nothing more I can do with my current setup.

It would be nice to get a second opinion on this too if anyone has spare time.

Cheers,
Dave

[Ivor]

I suspect you're right Dave. Given that you've eliminated a cable issue and possible room acoustics you're left with the conclusion that the Airtight has revealed something in the Ushers. It's not a water-tight conclusion of course, this is hifi after all.
there is a truism in hifi that when you upgrade (or even move sideways) you risk exposing a characteristic in another piece of equipment. It's all about the synergy.

Of couse Kharmas are not your only option either, take your time, consider all options.

[Diapason]

How very annoying. As time goes on I'm convinced that system brightness is the biggest plague in high-end audio. I also would have expected a thoroughly liquid treble from the Airtight, but then again I've also heard that it's on the brighter end of the sonic spectrum. I'm certainly not a believer that valves=smooth treble because I've come across plenty of counter-examples. FWIW, I'm not even 100% convinced Kharmas will solve this particular problem, as they can be lean (ish, it's all relative!) in the treble themselves. That said, amps don't always interact with speakers the way you're expecting, so who knows. Certainly Ciaran's Airtight/Kharma combo has no obvious problem with treble that I've noticed.

So, what to do? I'm loathe to suggest tube rolling, but.......!? Also, I'd definitely *try* a different speaker cable. You'd just never know.

[DaveF]

Certainly Ciaran's Airtight/Kharma combo has no obvious problem with treble that I've noticed.

Well that's the one hope I'm holding on to. I would hope that all the Airtights have a similar family sound. I did also read or had a comment from someone one time that nobody uses Nordost cables with Airtights. My Nordost's though are just a nice chunck of copper, nothing fancy or peculiar about it at all, so surely it makes little difference???!!

There is the remark in one Usher review that a good solid state amp is the preferred choice. The bass driver is well mechanically damped so it needs a bit of oomph to get it going. Perhaps this is awkward for the Airtight and the rest of the spectrum is suffering a bit as a result. The Airtight never sounds strained though but the bass is lighter than the Gamut which I guess is expected.

A home demo of the Kharmas for a good solid 2 weeks is a must now. I know what I'll be looking for and the exact recordings needed to illustrate the issue so it should become apparent very quickly if the Kharmas work or not. Actually since the problem does not appear to be room related a demo in the shop might also give a quick result.

All of the Airtight reviews remark on a liquid treble and how wonderful it is with vocals. My issue is also here with vocals sometimes so after adding everything up, the finger points to the Ushers. They never sounded like this with the Gamut or even the Krell 400xi before that. Notice a pattern in the amps there......big solid states with great bass control and current delivery.

[Diapason]

Actually, most of the treble brightness (or brittleness) I've had in my current setup has been a function of under-powered amps. You might be onto something.

The ATM-2 is 80W, right? That'll definitely be enough for Kharmas anyway.

[DaveF]

yip the ATM2 is 80 watts. Ciaran gets great sound with 55w when using his Airtights in triode mode so yeah I would imagine the ATM2 has enough in reserve for the Kharmas.

[Ivor]

I wouldn't think there's a question mark over power from the amp.
Try sand loading (or whatever material) as you're still not getting the best from those speakers until you remove any energy loss through movement. That's not usually related to treble but still needs to be done. Are the speakers on spikes? Spikes on coins?

[DaveF]

I wouldn't think there's a question mark over power from the amp.
Try sand loading (or whatever material) as you're still not getting the best from those speakers until you remove any energy loss through movement. That's not usually related to treble but still needs to be done. Are the speakers on spikes? Spikes on coins?

The speakers are on 3 ceraballs each like a tripod configuration. Problem exists both with and without the ceraballs.
Believe me these speakers are built like a bank vault. They are absolutely rock solid and well planted to the floor. Even on the cereballs, you'd break your leg if you tried to kick the speaker over. The front baffle is 2 to 3 inches thick and the wood is quite thick too. I really doubt that there are resonances in the cabinet walls. But perhaps its internal but given the swept back shape I doubt this. Hard to know for sure without knowing what the internal chamber is like. Worth investigating of course.

[Ivor]

I wouldn't think there's a question mark over power from the amp.
Try sand loading (or whatever material) as you're still not getting the best from those speakers until you remove any energy loss through movement. That's not usually related to treble but still needs to be done. Are the speakers on spikes? Spikes on coins?

The speakers are on 3 ceraballs each like a tripod configuration. Problem exists both with and without the ceraballs.
Believe me these speakers are built like a bank vault. They are absolutely rock solid and well planted to the floor. Even on the cereballs, you'd break your leg if you tried to kick the speaker over. The front baffle is 2 to 3 inches thick and the wood is quite thick too. I really doubt that there are resonances in the cabinet walls. But perhaps its internal but given the swept back shape I doubt this. Hard to know for sure without knowing what the internal chamber is like. Worth investigating of course.

That answers that then! I suspected as much but was just thinking out loud... or on a forum anyway.

[Claus]

Tightning screws around the tweeter is another possible solution . I have had my share of valve issues though mainly with guitar amp.. very frustrating. hope you find a cure somehow.