Are my BHK 300s too powerful for my speakers?

Audio Components Amplifiers
1

I recently upgraded from from an Ayre AX-7e integrated amp to a pair of BHK 300s and BHK pre. My speakers are Martin Logan Impression 11A, with recommended amp power of 20—550 watts per channel, at 4 ohms. It was my understanding that a slightly more watts in the amp would not be an issue when driving the speakers.

With the Ayre, my system always felt lacking in bass, and I mostly attributed this to the electrostatic speakers. I used the ARC room correction on the speakers. The Martin Logan’s also have a knob to adjust the bass level, and I would set it to +1db.

After the upgrade there is way way more energy in the system and the lower frequencies. Basically it makes my ears hurt at normal volumes unless I turn down the base level knob on the speakers down to the -10db lower limit, and even then the bass thins out, but the system is still fatiguing.

Is it expected to get such a a drastic change on amp upgrade? Could it be a faulty component or, a component mismatch causing this? Any suggestions are welcomed. Thanks.

My full system:
(Powered by Power Plant 3)
Ayre QB-9 DAC
Ayre Signature XLR Cables
PSA BHK Preamp
Transparent Reference XL XLR Cables

(Powered by Power Plant 15)
2 x BHK 300
Audioquest Wild Wood Speaker cables
2 x Martin Logan Impression ESL 11A

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In short, no. You shouldn’t be dialing in your volume using the numbers on the volume dial. Different components have differing gain settings. Use an SPL meter on your phone to dial into ~75dB or whatever is comfortable for you.

The rest is a matter of setting up your speakers again. If you’re going from room correction to no room correction, setup is even more important. There are many threads in this forum on pointers for speaker setup. If bass is too heavy, pull your speakers away from the walls. If your vocals are too forward, pull your speakers away from each other. If your highs are too hot, toe your speakers away from ear.

Good luck.

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That makes sense. And I was not expecting to be listening on the same number on the volume dial between the old and new system. The difference is however that with the new system the bass is way more prevalent relative to the highs. So I either have to listen at very low volumes, and the vocals and instruments are very quiet, or increase the volume and hurt my ears.

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Since your speakers have a bass EQ knob, turn them down to where you’re comfortable.

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And you are probably going to have to either re-position your speakers or your seating position.

1 Like
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5 times the wattage is quite a hike in sound pressure level, which is not easy for the human ear.
I read the following on ML’s site:
Impression ESL 11A reveal the pure emotional impact of the performance, with nothing between your audio and your ears. Featuring a 11-inch (CLS™) XStat™ electrostatic transducer, dual 8-inch PoweredForce Forward™ woofers powered by dual 275-watt Class-D amplifiers, and controlled by a 24-Bit Vojtko™ DSP Engine and ARC™ (Anthem Room Correction).
May be you could use room correction to fix your bass level?

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@vee is exactly right. Just start from scratch on speaker setup. And forget previous volume and level settings. Rely instead on a sound pressure level meter app to find and maintain a listening level that you like… And I would not be changing anything, cables, etc. at this point.
Just get the setup correct. It can actually be a fun process if you take your time, approach it methodically and know that you’ll get there eventually.

2 Likes
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Welcome, @robimil !

Think of a powerful amp as a high horsepower car engine. The car will not do anything you do not tell it to. Apply the throttle to obtain the acceleration or speed you want, but the extra power is there if you ever need it.

This is the same as running a very powerful amp. Use the volume control to obtain whatever loudness you want. The speakers will be perfectly happy. Of course, just like the car, floor it indiscriminately and you may hurt something.

The much bigger danger is using an amp which is too small. Speakers are damaged - particularly tweeters - when the listener keeps turning up the volume driving the amp into distortion. The distorted signal can hurt the speaker.

I, too, find the BHK 300s to have amazing bass and needed to adjust my system in response to this change.

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Thanks all. I will start the placement from scratch and report back.

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Welcome @robimil I think you are going to be able to work things out with that system to a point where you really like the sound. Speaker placement is so critical to sound and so variable when changing equipment. Good Luck and definitely let us know what ends up working for you. Jim

1 Like
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How many hours do you have on the BHK 300’s?
You mentioned that even when you turned the bass level knob on your speakers down to -10db, your system was still fatiguing. This could be due to the amps not being fully broken in yet.

1 Like
12

Also, stats present a complex and challenging load for any amplifier. Due to their capacitive nature the load impedance drops as frequency increases so at the highest frequencies the speaker load can reduce to 1 ohm! Without proper EQ an electrostat can have a very peaky (too much highs) kind of response due to phase cancellation as you approach mid-band / midrange. Without this “shelving” filter (possibly built-in to your M-L passive crossover) they would sound tipped up. It could be that the BHK amps are much better at driving the stats (sounds like the woofers have their own amp) and you’re hearing a more accurate representation of the audio signal being fed to the crossover/EQ network.

3 Likes
13

I believe that’s the case. So why then did he experience an increase in the lower frequencies with the BHK 300’s?

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He went from a 60wpc Integrated amp to 300 watts per channel driving speakers that can take advantage of the power and more importantly, the current. Combine that with the different relative volume levels and his basic level of understanding for what was really going on and the ARC setup issues.

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But his Martin Logan speakers have self powered subwoofers, so going to a more powerful amp which only drives the mid-range and tweeters should not have affected the lower frequencies.

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When you turn the bass down is the frequency balance OK, but the sound itself is fatiguing? I am getting the impression there are two issues going on; too much bass and bad sound. Yes?

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That’s the impression I had as well, which is why I asked how many hours he had on his BHK 300’s.
Could be that they aren’t fully broken-in yet.

1 Like
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@Elk Yes, I also have been thinking that there are 2 separate issues. It is fatiguing even when the bass is turned down. I am also not convinced the frequency balance is OK if I turn the bass down. I basically had to turn it down all the way to -10db, which was concerning. I am going to play with speaker placement today and see if that is still the case if I move the speakers away from the walls.
@Gary_M The preamp has about 115 hours on it. I had a clicking noice when changing volume on one channel which was due to a bad tube, and PSA sent me a replacement pair. The “harshness” seemed to be more pronounced using this new pair. So I want back to the original one, as I don’t want to introduce more variables at this time.

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The BHK 300’s I got used, so probably already broken in.

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Hmm . . .

The 300s may not be broken in yet, but my experience is they sound great out of the box and certainly not fatiguing. Yet break-in could be at play.

Do you know the gain of the speaker’s subwoofer built in amp? Probably not, but we could compare it to the 300’s gain of 30.5dB. Do you know the gain of your previous amp? Perhaps the gain adjustment of the speakers’ subwoofers is insufficient. Even then I would not expect fatiguing sound.