Getting above 92dB

[Sky Saw]

My system is based on a pair of Ascent-i's driven by an 85wpc solid-state amp (Celeste W-4070se), a Copland 305mkII tubed preamp, a Meridian G08 CD player, Linn LP12, and a Moon 100D DAC fed by a M2tech Hiface2 usb interface from a Macbook. For the most part it sounds great, but once the sound levels get to 92-93dB the sound becomes hard and I need to turn it down a bit.

I have a large listening room (about 16 x 28 with 25ft ceiling), and it is open on 2 sides. I would like to be able to crank it up a bit more, but I don't know whether this sound problem at 92dB is related to my room acoustics, or if my amp is just running out of steam.

I get lots of bass in this size room from my Ascent-i, and my amp has no trouble producing frightening amounts of bass drum on things like Stravinsky's Right of Spring (the fantastic Reference Recordings version with Eiji Oue conducting), but when the rest of the orchestra hits 92dB, things start to fall apart.

Any thoughts - is it my amp, my room...?

Mark

 

[Rich]

With only 85 wpc trying to push the Ascent i's, I am guessing it is your amp clipping that is causing the harshness. One option would be to get another one of those amps and bridge them to double your wattage output. Another is to get a different amp and bi-amp your speakers. The Ascents sound incredible with a tube amp on the panels and SS amp on the woofers. Provide the Ascents with enough power and they will sound incredible no matter how loud you go. I speak from experience.

 

[amey01]

get another one of those amps and bridge them to double your wattage output.

That will only give you another 3dB!

Seriously though - at 92dB, if you enjoy this hobby, and want to continue to enjoy music for much longer into the future then you're already well into dangerous territory.....Think about that. You can't get your hearing back.

 

[edwinr]

The Celeste W-4070se seems to be a very good quality high current amplifier. It should have no problem driving the Ascent i's. I was thinking that if you get 'frightening' amounts of bass drum etc, then perhaps you're not over driving the amplifier. If an amp is going to run out of steam (wattage wise) - this is where you'll hear it.

So you have problems with the higher frequencies when things get busy. Just maybe the amp doesn't like the the very low impedance presented by the panels at higher frequencies? Even though the amp nearly doubles it's power into 4 ohms - 2 ohms could be it's achilles.

 

[MrBT]

What is the listening distance or distance from speakers to the point you measure 92db? Is it 92 at peaks?

Classical music can have very wide dynamic range. Quite often can be more than ~50db. You are reporting problems at 92db but what about realistic peaks of more than 100db. These over 100db peaks can sound nasty with 85w and such a large space.

 

[twich54]

Classical music can have very wide dynamic range.

not 'can'....it does !

 

[Sky Saw]

What is the listening distance or distance from speakers to the point you measure 92db? Is it 92 at peaks?

Classical music can have very wide dynamic range. Quite often can be more than ~50db. You are reporting problems at 92db but what about realistic peaks of more than 100db. These over 100db peaks can sound nasty with 85w and such a large space.

Yes, thanks for clarifying. I tend to listen to a lot of music that has very wide dynamic range. I sit 10-12 feet from the (midpoint between the) speakers, and measure the dynamic peaks at 92-93dB.

I recently downloaded one of those free spl meters for my iDevice, and am looking at the maximum values, so the typical listen volume is probably within the safe zone as far as hearing goes. With system peaks at 92-93dB, the sound loses its fullness in the loud parts, so I never listen to music louder than this. If others are able to enjoyably achieve peaks higher than 92dB, then I guess I could use more power.

I had thought of getting another W-4070 amplifier and horizontally bi-amping, but after reading Edwin's message, maybe a different, more powerful amp is a better way to go?

 

[Rich]

I had thought of getting another W-4070 amplifier and horizontally bi-amping, but after reading Edwin's message, maybe a different, more powerful amp is a better way to go?

Honestly, I think this is your best solution. My personal take on the Ascents is that they do best with 350 to 400 wpc. I am driving mine with a Pass Labs X-350.5 and it powers them as loud as you would want to go without any edginess. I have also, in the past, powered them with a Conrad Johnson Premier 140 tube amp on the panels and a basic 200 wpc SS amp on the woofers. That was sublime.

 

[Rich]

The Celeste W-4070se seems to be a very good quality high current amplifier. It should have no problem driving the Ascent i's.

High current is good for handling the impedance swings, but it does nothing to keep them from being over-driven. Simply put, 85 wpc is not enough power to drive the Ascents to high spls in a decent size room. So I think your conclusion they should have no problem driving them is absolutely false. They will distort at the high SPLs, causing the edginess and the soundstage/imaging will fall apart.

 

[gordonmenninger]

I also agree that you need to get a way beefier amp. 85 watts is peanuts. Look into used Krells, Plinius, Bryston, etc and get at least 300wpc int 8 ohms.
My Krell puts 600w Into 4 ohms on my SL3's and double that when they dip down to 2 ohms and they play VERY loud if I want them to with absolutely no strain! It's all about the amp baby! 25' ceilings is quite high though, you may need to look into a concert rig LOL!

 

[Sky Saw]

High current is good for handling the impedance swings, but it does nothing to keep them from being over-driven. Simply put, 85 wpc is not enough power to drive the Ascents to high spls in a decent size room. So I think your conclusion they should have no problem driving them is absolutely false. They will distort at the high SPLs, causing the edginess and the soundstage/imaging will fall apart.

I think Edwin is right - the Celeste does a great job of driving my Ascent-i's and sounds great doing so, with deep and clear bass; however, I have this volume ceiling, which I am getting the impression is probably from reaching the boundary of what the Celeste can realistically do. But wow, 350-400 wpc? That's monster amp territory. I was thinking of something like the Moon W-5 (190wpc).

 

[Bevensee]

I wonder how the room is. 92 dB measured with an Iphone app is quite loud. If the room has a lively acoustic, it will overload way before this, no matter the amp. Nevertheless, 85 WPC do sound a bit wimpy. So perhaps a bit of room treatment + a better amp will do the trick. But mind your hearing!

BRW: I can highly recommend Vincent poweramps. They are incredibly powerfull and at the same time sweet sounding. In my opinion, they have no serious competitors at the price.

 

[Bernard]

But mind your hearing!

This cannot be stressed enough.

 

[JonFo]

My take is that a good part of the problem is room acoustics, as these ESLs can really put out a ton of mid to high-frequency energy and cause various room resonances to get excited.

depending on how your speakers are set up, the 'hardness' of walls/windows around the room, this can be quite fatiguing at high volumes.

My recommendation would be to start by at least trying to absorb some of the ESL rear wave as it hits the walls just behind and side of it to ensure you A) reduce the amount of reflected energy from the out-of-phase rear wave B) get a cleaner first-arrival from the front of the panels with less comb-filtering effects.

Please check out our Room treatment sub-forum for some ideas and products that can help here.

As a data point, in my fully treated custom room, I can hit 105dB SPL clean with no ringing in the room. Peaks of 92 or so in normal listening are not at all fatiguing now.

 

[Rich]

I think Edwin is right - the Celeste does a great job of driving my Ascent-i's and sounds great doing so, with deep and clear bass; however, I have this volume ceiling, which I am getting the impression is probably from reaching the boundary of what the Celeste can realistically do. But wow, 350-400 wpc? That's monster amp territory. I was thinking of something like the Moon W-5 (190wpc).

Just depends on how much "headroom" you require. As Adam stated above, a doubling of wattage is only going to give you about 3 db of extra headroom. I agree with JonFo that poor acoustics can cause lots of problems, but I still think your main problem is that your amp is reaching its limits and distorting when you turn up the volume. Acoustic treatments will help with ringing and comb filtering, but won't do anything to help an amp that is distorting. A quick way to judge the difference is to hang up some heavy blankets behind your ascents and see how they sound at peak volumes, then take down the blankets and sub in a demo amp in the 200 wpc or more range and see how they sound turned up. That should give you an idea of where your biggest problems lie and what the possible solutions are.

 

[Tosh]

It might be compression in the recorded music reaching an 'irritation threshold'...

As to enough power, the quickest and easiest thing to try for an indication of whether or not the amp is running out of headroom is to disconnect the jumper to the woofer and run the amp to the ESL terminals alone at the same level as before and hear if it still sounds 'hard.' (Switch off amp before re-connecting.)

 

[MrBT]

Let's not get too serious about 92db at peaks. Damaging hearing at 92db is generally accepted statement (OSHA allows 8 hours of exposure to 90 dBA) and for prolonged exposure to such SPL. Keep in mind that even when you walk on busy city streets you may be exposed to much higher SPL peaks. Are you guys saying that musicians are deaf because of "prolonged exposure" to live, not amplified concert. In NYC philharmonics I measured peaks quite above 100db!! (107db if my memory serves me well - "pictures at exhibition" sitting at about 20th row from orchestra).

Correct me if I'm wrong....

 

[edwinr]

With only 85 wpc trying to push the Ascent i's, I am guessing it is your amp clipping that is causing the harshness. One option would be to get another one of those amps and bridge them to double your wattage output. Another is to get a different amp and bi-amp your speakers. The Ascents sound incredible with a tube amp on the panels and SS amp on the woofers. Provide the Ascents with enough power and they will sound incredible no matter how loud you go. I speak from experience.

Rich, if you were to bridge the W-4070se, would this adversely affect this amplifier's ability to drive to impedance loads? I know you would get more power per se, but I'm wondering if bridging could come at a cost when driving the panels at higher frequencies (?) I'm just not sure how this bridging idea works.

 

[Rich]

Rich, if you were to bridge the W-4070se, would this adversely affect this amplifier's ability to drive to impedance loads? I know you would get more power per se, but I'm wondering if bridging could come at a cost when driving the panels at higher frequencies (?) I'm just not sure how this bridging idea works.

I don't believe so. But that is really a question for the manufacturer. Bridging just takes a stereo amp and makes it a mono amp. It's ability to handle varying impedances shouldn't be affected.

 

[jmschnur]

Not sure about impedance being invariant in bridged mode for amp. You will need to check.


J