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Speaker shootout update; aggressive treble eliminating some (fairly?)

I've been trying out speakers in a complicated shoot out, both bookshelves and towers — all in my home with my gear. I'm looking for speakers obtainable up to about $4k but could go up (or down) a bit if the right thing came along.

Basic facts: All speakers were run in at least 100 hours. Room is 27 x 14 x 6.5 ceilings. Powering with all QS tubes, 60w, NOS, tube R2R dac, and decent cables. No terrible reflection points; room not overly live or dampened. REL R 328 sub available but I did most listening without it.

Recent auditions, type:

Klipsch RP 600-M (budget singleton of the group)
Fritz Rev Carbon 7 mk II (bookshelf, 2 way, soft dome)
Focal 936 (tower, 3 way, inverted metal)
Martin Logan Motion 60s XTi (tower, 3 way, AMT)

Coming soon:

Salk SS 6M (bookshelf, 2 way, beryllium)
Dynaudio Evoke 30's (tower, 3 way, soft dome)

Let me speak just to the problems, rather than what was good about the speakers. So far, I've found the Klipsch, Focal, and especially the Martin Logans were all too bright — forward, aggressive, "turn it down" treble.

The ML's were the most impossible to tame and hardest to listen to on more tracks. (I did a lot of hanging of towels and other dampeners and other soft things to try to see if I could bring them to heel. I varied the recordings used. Changed cables/wires. No luck.)

The Focals were occasionally too bright; their bigger problem was a bit too much energy in my small listening space. They were better when I plugged their ports with socks.

I'm looking forward to how the next two speakers sound. The Dynaudio towers, I notice, are 10 inches shorter and half the weight of the other towers; not sure what that might mean, but it could just be right size for my space. I'm looking forward to seeing if the Salks bring more detail to the treble without also being too rolled off or harsh.

Hearing is very personal for physiological and taste reasons. However, if anyone has any thoughts about why I might be experiencing some of the phenomena I am (harsh treble, especially) based on my room or gear, etc., that might help me understand factors I'm not fully appreciating. Thanks.


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helomech
1,740 posts
 
@helomec,
did you audition the older "XT" or latest "XTi" version? Updates for the XTI version mention  no tweeter or crossover changes, but I’m suspect. The woofer surrounds in the new XTi version are noted as upgraded and  "stiffer". I’ve heard the older 60XT many times, and own the smaller ML40XT for another setup, and they are not overly bright, fairly neutral in fact. As noted before, found a spike on the response graph between 10k-15khz.

Still kinda wondering if there was a change in material used in the AMT diaphragm or crossover with the new XTI version...no proof, just curious.

I auditioned the older XTs. I noticed the spike in the measurements of one online review, but a spike in that octave is most likely to result in a sense of "air" and atmosphere, not brightness. I do wonder if these AMT drivers might require a break-in period where the binding/matrix material has to undergo micro-cracking, thereby allowing the pleat to relax, not unlike a conventional spider material. Not all AMTs are created equal that's for sure. The ML AMTs are far superior to those used by Golden Ear.
decooney
2,246 posts
 

@helomech
The original Dr. Von Heil AMTs did mellow out some over time, and it was the crossovers/caps settling too, not just the diaphragms. I worked on the assembly line at ESS early 1980s, where it was all invented. Seen some variations since the patent expired on the AMT. My own ML XT40s did settle some over time for my HT setup. Smoother now for sure. I agree all AMTs are not created equal. My own current custom speakers with great heil amt units sound smoother with larger presentation than all mentioned here so far. Over time, messing around, learned it really comes down to a very high quality crossover and corresponding drivers to get the right tone and staging one might be looking for. One thing for sure, when you get the right AMT speaker setup paired with really good tube amps, with really good tubes, its very enjoyable to listen to. :) 
 
audiokinesis
2,753 posts
 
One possible source of aggressive treble is poor amp/speaker matching, but this is not something which is obvious to most people. One would think good amp + good speaker = good results, but not necessarily.

If I understand correctly, the amplifier is a transformer-coupled tube amp. This kind of amp tends to deliver approximately the same amount of power into a fairly wide range of impedances.

On the other hand a solid state amp delivers increased wattage into an impedance dip, and decreased wattage into an impedance dip.

Let’s walk through an example:

So suppose we have an 8 ohm speaker with a 16-ohm impedance peak at 4 kHz. With a solid state amp, when the amp is delivering 1 watt into the 8 ohm nominal impedance, it is delivering 1/2 watt into that 16 ohm impedance peak. The designer probably assumed that a solid state amp would be used, so this speaker’s output is "flat" (or whatever the designer intended) with the amp delivering 1/2 watt into that 16 ohm peak.

Now let’s use a tube amp. The tube amp delivers approximately the same amount of power into that 16 ohm peak as into the nominal 8 ohm impedance. So at 4 kHz, the speaker is getting 1 watt rather than the 1/2 watt the designer intended. So we have a 3 dB peak at 4 kHz. That’s enough to transform "smooth treble" into "aggressive treble".

Rather than ditching your imo very nice Quicksilver amp(s), you might want to consider speaker compatibility with tubes.   I can go into a bit more detail about it if you'd like. 

Here is a paper written by a tube amp designer which goes into this from his perspective, mine being the perspective of a speaker designer:

http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html

Best of luck in your quest, wherever it takes you.

Duke
jtcf's avatar
jtcf
1,620 posts
 
@decooney  today TungSols 7581A (EL34) were in the Quickies running the Harbeths,still using lamp cord.Very lively and dynamic!The transients had some bite to them.There was little bit of a 'gritty' overlay to the presentation which actually enhances string instruments.Tomorrow the KT150s are up.
audiokinesis
2,753 posts
 
Regarding the ASR review of the Salk WOW1 speakers:

That speaker was designed to be used UP AGAINST THE WALL, and its overall frequency response curve is imo CORRECT for a small speaker which will be getting a lot of boundary reinforcement from that wall. If the WOW1 had plenty of low end, in the measurements, it would sound bloated when placed against the wall.

Regarding the dip at 600 Hz, dips are less audible than peaks and 600 Hz is NOT a bad place to have a dip. There are three frequency regions I pay particular attention to, where erring on the side of dippage is preferable to erring the other way, and arguably preferable to "flat". 600 Hz falls within one of these regions.

Finally, Amir did not audition these speakers up against the wall, so it is not surprising that he didn’t like them. He tries to be as consistent as possible in his measurement and audition conditions, which is not a bad thing, but it does result in some measurements being imo incompletely interpreted, and in some speakers being auditioned under conditions they were not designed for.

So imo ASR’s review of the Salk WOW1 should be taken with a pinch of salt.

Duke
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