4bsst2 clipping with Maggie 1.7

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a.wayne

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #40 on: 31 Oct 2015, 01:21 am »
Doesnt the Bryston have clip lights , amplfiers without clip lights could be clipping without being noticed on peaks. The maggies are 83db/m/2 watts

RDavidson

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #41 on: 31 Oct 2015, 01:45 am »
I use an AVA 400R with my 1.7s and have cranked them a few times with no problem.  I am shocked that your Bryston was clipping, that amp is no slouch.  I wonder if your amp could have something wrong with it.  Bryston have fantastic customer service.  You should send it in for a checkup before you dump it.

This has been asked a couple of times :
How big is the room?
What's your listening distance?

90db peaks is not all that loud.

Note the instruction manual says the specifications, including the 86db sensitivity of the 1.7, is "in normal installations." This tells me that the speakers may be closer to 80db sensitive in an anechoic chamber. Yikes!
http://www.magnepan.com/manual_17#OptionalTweeterAttenuation
« Last Edit: 31 Oct 2015, 02:53 pm by RDavidson »

I.Greyhound Fan

Re: 4bsst2 clipping with Maggie 1.7
« Reply #42 on: 31 Oct 2015, 03:21 am »
error

I.Greyhound Fan

Re: 4bsst2 clipping with Maggie 1.7
« Reply #43 on: 31 Oct 2015, 03:26 am »
Is this from personal experience?
Have you cranked them up to see how they work at more demanding levels...  very curious...

This is from personal experience.  I wrote a review on the 600R for AVA.  I had both the 400R and 600R in my system.  Both blow the A21 out of the water in dynamic's, speed, detail and resolution.  They are much musical.  I also have 2 friends that post on this forum.  One has the 400R with the 1.7's and the other has the 600R with his 3.7's.  I have heard both systems many times.  One thing that the R amps do is sound great at low volumes.  They tend to keep their dynamics.  Not even my Pass amp does that.  I had the R amps up to very loud volumes and they did not break up.

My room is 17x17 with 10' ceilings.  Listening position is 14' away from the speakers. 

*Scotty*

Re: 4bsst2 clipping with Maggie 1.7
« Reply #44 on: 31 Oct 2015, 03:27 am »
The truth of the matter is the RatShack meter will not measure peaks accurately on any setting. It just cannot respond fast enough and it was never designed for this type of measurement. Some of the apps on Google play have a fairly fast response time, SPL Spectrum Analyzer is pretty fast, it might register peaks as much as 15dB higher that the RS meter doesn't even know are there. I am not claiming that the SPL Spectrum Analyser app is in any way accurate but it might give a more meaningful reading than the RS meter.
 I suspect that you are hitting at least 105db when applying more than 400watts. By the math based on the claimed sensitivity, 20watts should give you 96dB and 200watts should net you 105dB. Even allowing for a miss on the sensitivity, 200watts in should allow at least 96db continuous output without clipping.
There should also be a fairly sensitive SLP/RTA meter app available from iTunes.
Scotty

Quiet Earth

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #45 on: 31 Oct 2015, 03:55 am »
The truth of the matter is the RatShack meter will not measure peaks accurately on any setting. It just cannot respond fast enough and it was never designed for this type of measurement.

No arguement there. I don't think we are trying to imply they are accurate. Or consistent. But I think a RadioShack SPL meter report gives us a much better indication of volume than "I played it loud" or "I cranked it up". Know what I mean? It's a better kind of crude measurement.  :D

This has been asked a couple of times :
How big is the room?
What's your listening distance?

We don't know how big the room is or the speaker placement relative to wall boundaries, but we do know that he sits 15 feet away.

The maggies are 83db/m/2 watts

Wow, really? That's pretty low. I wonder if that is an optimistic number considering the low SPLs nocrapman is getting with his 300 watt amp.

I still wonder about the source though....


Phil A

Re: 4bsst2 clipping with Maggie 1.7
« Reply #46 on: 31 Oct 2015, 01:26 pm »
Doesnt the Bryston have clip lights , amplfiers without clip lights could be clipping without being noticed on peaks. The maggies are 83db/m/2 watts

Yes it does:

"L·E·D INDICATORS
Each SST2 channel has a LED indicator to monitor the following conditions:
Unlit - indicates channel has no power.
Red - indicates channel is muted (power-up)
Green - indicates channel operation is normal.
Flashing Red - indicates channel clipping.
Orange - indicates channel thermal shutdown."

At one point many moons ago I also owned a 4BST and it wasn't enough power in my room for the Thiel 7.2s (was OK for 2.3s).  My old room was probably 7,000 cubic feet and open to other spaces.  I was shocked at the time that I didn't have enough power as on peaks a couple of times it went into momentary clipping.

josh358

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #47 on: 31 Oct 2015, 02:18 pm »
The truth of the matter is the RatShack meter will not measure peaks accurately on any setting. It just cannot respond fast enough and it was never designed for this type of measurement. Some of the apps on Google play have a fairly fast response time, SPL Spectrum Analyzer is pretty fast, it might register peaks as much as 15dB higher that the RS meter doesn't even know are there. I am not claiming that the SPL Spectrum Analyser app is in any way accurate but it might give a more meaningful reading than the RS meter.
 I suspect that you are hitting at least 105db when applying more than 400watts. By the math based on the claimed sensitivity, 20watts should give you 96dB and 200watts should net you 105dB. Even allowing for a miss on the sensitivity, 200watts in should allow at least 96db continuous output without clipping.
There should also be a fairly sensitive SLP/RTA meter app available from iTunes.
Scotty
Precisely! SPL meters -- not just the Rat Shack -- are designed to take averaging rather than peak readings. Which is great for noise exposure measurements and judging subjective loudness, but not so much for what we're doing.

I suggest Audio Tool for Android, it's absolutely superb and it's only $8:

https://play.google.com/store/apps/details?id=com.julian.apps.AudioTool&hl=en

A lot of pros use it for quick measurements with their phones, it's that good. Calibrate it to the Radio Shack with a test tone. It will give you real peak readings as well as spectrum analysis and even RT-60, great for the times when you don't want to haul out your measurement mic and computer. The internal mic won't however read over 100 dB SPL (Android limitation) and won't have great freq response either. So I've ordered the little Dayton phone measurement mic for $19, it should be here this afternoon. It has an individual calibration curve that you can load into Audio Tool.

josh358

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #48 on: 31 Oct 2015, 02:40 pm »
Funny you should bring up this topic. I have a pair of MMGs, smaller than the 1.7.s no doubt. I have a tube amp from a reputable company which has three large transformers producing what I felt was enough current to drive the MMGs. After a couple years, the amp failed. The suspect was the transformers. At this point, I agree that they are demanding on amplifiers. Now I use a Parasound A21, but I think I could use something even beefier with current.
I don't think you'll gain from more than an A-21 on the MMG's. I had a pair -- wonderful speakers, but while they'll gobble power, the bass starts to intermodulate and they sound veiled when you push their SPL. So you're unlikely to push them as hard as the bigger models. You can get higher SPL's out of them if you add a sub and take some load off the woofer, Davey has done that with success.

josh358

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #49 on: 31 Oct 2015, 02:48 pm »
I think you may be thinking of Innersound. I believe, but don't quote me on this, that Innersound either used Sanders technology or were a direct spin-off of the Sanders line, designed for domestic applications where the big Sanders speakers just wouldn't fit.

No, Magtechs don't show up used very often. People who have them, seem to love them.
Yes, verified that the Innersounds were an earlier Sanders design. Not cheap, though:

http://www.avsforum.com/forum/209-audio-gear/1889473-innersound-dpr-500-mkii-amplifier-attention-electrostatic-owners.html

RDavidson

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #50 on: 31 Oct 2015, 03:07 pm »
Thanks Josh358. I didn't think I was crazy thinking Innersound was basically a branch of Sanders. :thumb:

A listening distance of 15 feet = about 5 meters.
The speakers are likely somewhere in the vicinity of 83db sensitive @ 1 watt / M. To hit 105 db peaks at 5M, one would need 3962 watts peak power (before clipping). :oo
To hit 90db average, one would need 125 watts continuous, but 9db of headroom one would require 995 watts.

So if the OP is rocking out at 90db @ 5M, and the sudden drum hits are in the vicinity of +6db or more, they'd certainly cause the clipping lights to flash.

http://www.crownaudio.com/en-US/tools/calculators

josh358

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #51 on: 31 Oct 2015, 04:00 pm »
Thanks Josh358. I didn't think I was crazy thinking Innersound was basically a branch of Sanders. :thumb:

A listening distance of 15 feet = about 5 meters.
The speakers are likely somewhere in the vicinity of 83db sensitive @ 1 watt / M. To hit 105 db peaks at 5M, one would need 3962 watts peak power (before clipping). :oo
To hit 90db average, one would need 125 watts continuous, but 9db of headroom one would require 995 watts.

So if the OP is rocking out at 90db @ 5M, and the sudden drum hits are in the vicinity of +6db or more, they'd certainly cause the clipping lights to flash.

http://www.crownaudio.com/en-US/tools/calculators
A valid point! That calculation actually won't be precise because dipoles fall off linearly rather than as the square with distance, but on the flip side have less room gain. There's a calculator somewhere that has an option for dipoles. But I think the bottom line is that Maggies are inefficient and if you want to play them at higher levels you need a lot of power into 4 ohms. The .7's are a very easy amplifier load, so you're getting basically the full power of the amp, but they also dip a bit below 4 ohms in the mids and drop from 4 ohms at 3 kHz to below 2 ohms in the highs -- what's more, they do that where the phase angle is most extreme (although "extreme" probably isn't a good way to describe a -35 degree phase angle!).

I'm beginning to think based on my experience and what I read that it's overoptimistic to expect the typical amp to do well with inefficient 4 ohm speakers. This isn't a matter of RMS specs -- I'm sure a manufacturer like Bryston is honest about those -- but rather of dynamic behavior, e.g., peak headroom, voltage droop, recovery time. My old Hafler had problems which were analyzed by Jung in The Audio Amateur, the XPA-2 apparently has problems driving the larger Maggies -- there seem to be chronic problems with SS amps that are basically optimized for an 8 ohm load.

Nothing that can't be solved by going to the next model up. :-) Biamping helps too, you can put a big pro amp on the bass. And most people don't listen at these levels -- I think people should measure before they go off to buy a bigger amplifier!

josh358

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #52 on: 31 Oct 2015, 04:14 pm »
It's not completely clear from the Magnepan website whether or not the 86dB sensitivity rating is measured quasi-anechoically or in the "average" living room, but 500watts into 4ohms with give you a little over 109dB maybe somewhat louder in your listening room,or not.
I would say from an electrical standpoint that Maggies are easy to drive, but they are not the most sensitive loudspeaker out there.
 You might download some of the SPL meter apps from Google play or iTunes and measure how many SPLs you have at your listening position when the amp is clipping. You have something of a problem, even another 3dB of volume, if possible, will require an amp capable of producing 1000 watts into 4 ohms.
Scotty

Interesting question. Someone should try a gated measurement at 1 meter. That being said, my IVA manual says that the speakers "exceed 110dB RMS at the listener's seat in a 16' x 25' room with an amplifier rated at 200 watts at 8 ohms," so a bit under 400 watts at 4. Taking room gain and line source radiation into account and assuming a 3 meter listening distance, that's pretty close to their stated sensitivity spec.

srb

Re: 4bsst2 clipping with Maggie 1.7
« Reply #53 on: 31 Oct 2015, 04:15 pm »
Many of us have a favorite sounding speaker, but if I couldn't drive a particular speaker to my satisfaction (and without clipping) in an average home room size with a typical high-end 300W/600W $5,000 amplifier, I would personally have to rethink my choice of speaker.

Steve

RDavidson

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #54 on: 31 Oct 2015, 04:16 pm »
Yup. There's a limit to what can be done in a stereo amp before power from the wall becomes the limiting factor, in which case monoblocks are the next step for speakers like Maggies in a large room and/or far field listening.

Of course, another option (though more tricky in a 2 channel setup) is to high pass the mains and add a sub. If one isn't averse to using pro amps, this becomes much easier as pro amps often have crossovers. I think others have suggested the Crown XLS amps. That'd be a great option. HIGH power. Relatively low cost. Digital crossover. $299 for an XLS2500 :o
http://www.musiciansfriend.com/pro-audio/crown-xls2500-drivecore-series-power-amp?cntry=us&source=3WWMWXGP&gclid=COi37cCN7cgCFRCqaQodpqwJjA&kwid=productads-plaid^131990803467-sku^485462000000000@ADL4MF-adType^PLA-device^m-adid^83738188347

Here's the newer 2502
http://www.crutchfield.com/S-LEYzMMkMTzc/p_859XLS2502/Crown-XLS-2502.html

Phil A

Re: 4bsst2 clipping with Maggie 1.7
« Reply #55 on: 31 Oct 2015, 04:29 pm »
Many of us have a favorite sounding speaker, but if I couldn't drive a particular speaker to my satisfaction (and without clipping) in an average home room size with a typical high-end 300W/600W $5,000 amplifier, I would personally have to rethink my choice of speaker.

Steve

I'm with you on that one.  Even with the impedance of my current speakers and they are fairly efficient (90db, Stereophile tested them at 90.7), today I'd probably look at something different.  I was hesitant when I got my old Thiel 7.2s many moons ago (in a room that was about 7,000 cubic feet and open to other spaces) and found out my suspicions were with along the right path (and that was one of the reasons I never got a Magnepan in that room - really considered it when I decided to sell the 7.2s).  I have Ohm Microwalsh Talls in a small bedroom (about 11x13 with a 10 ft. ceiling) secondary system and I really like the speakers but would not recommend them in a bigger room.

josh358

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #56 on: 31 Oct 2015, 04:35 pm »
Many of us have a favorite sounding speaker, but if I couldn't drive a particular speaker to my satisfaction (and without clipping) in an average home room size with a typical high-end 300W/600W $5,000 amplifier, I would personally have to rethink my choice of speaker.

Steve
Well, always a matter of tradeoffs. Maggies are bargains as speakers go but you do need a bigger amp. The price/performance ratio is good enough so that this usually makes sense. (Magnepan could increase the efficiency by using neodynium magnets, but the magnets would cost more than a bigger amp does.)

That being said, I'm experimenting with a Crown 2500 that cost me all of $300 and it sounds great on my IVA's. Does it sound as good as the A21? No, but it's good enough so that if I didn't have the A21, I'd be delighted to live with it.

Perhaps more to the point, few audiophiles listen at levels that require this kind of amplifier power. A nightclub hits 120 dB, the OSHA limit, acoustical jazz can hit 127 on the peaks, acoustical classical can hit 122, but those are all outlying figures and not really suited to everyday listening to compressed recordings (as they almost all are) at home, and most consumer speakers can't even hit those levels without bursting into flame. When some guys on the Audio Asylum posted peak SPL readings they were *much* lower, even if you add on 10 dB since the meters don't read peaks.

I also think though that those with smaller Maggies should consider upgrading to a larger model before getting a huge or super-costly amp. There will be a bigger improvement in sound and typically the smaller Maggies start to sound strained before the amp runs out of steam. I think I'd want 3.7's at least before I considered something like a Pass or Magtech. Also, with the small models, a sub will likely give you more of an improvement in maximum SPL than a big amp will.

I.Greyhound Fan

Re: 4bsst2 clipping with Maggie 1.7
« Reply #57 on: 31 Oct 2015, 05:23 pm »

I also think though that those with smaller Maggies should consider upgrading to a larger model before getting a huge or super-costly amp. There will be a bigger improvement in sound and typically the smaller Maggies start to sound strained before the amp runs out of steam. I think I'd want 3.7's at least before I considered something like a Pass or Magtech. Also, with the small models, a sub will likely give you more of an improvement in maximum SPL than a big amp will.

I agree and disagree with this.  While moving up to bigger models of Maggies does improve the sound, a good amp and preamp will take your speakers to another level.  My going from the A21 to the Pass X250 was a major improvement.  And going from an AVA Ultra Plus tube preamp to a Pass X1 and then a BAT VK51se preamp was another major jump.  I then upgraded my DAC to a Luxman DA-06 which was the icing on the cake. I bought the BAT and Pass gear used at great savings.  Before upgrading my electronic's, I thought about upgrading to the Maggie 3.6's.  I think that I made the right decision as the 3.6's would not have sounded as good with my older gear.  I almost bought the 3.6's instead of the 1.6's and I had my wife's blessing but my electronics were not up to par at the time so I went with the 1.6's.

I do think that going from the MMG's to the 1.7's is a good place to start however.  I own a pair of MMG's and while they image a little better than my 1.6's, they certainly do not sound as good.

I am now at the point that I am considering upgrading to the 3.7's or possibly upgrading my amp to an X250.5 and my preamp to a BAT VK52se or VK32se.

a.wayne

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #58 on: 31 Oct 2015, 07:11 pm »
The truth of the matter is the RatShack meter will not measure peaks accurately on any setting. It just cannot respond fast enough and it was never designed for this type of measurement. Some of the apps on Google play have a fairly fast response time, SPL Spectrum Analyzer is pretty fast, it might register peaks as much as 15dB higher that the RS meter doesn't even know are there. I am not claiming that the SPL Spectrum Analyser app is in any way accurate but it might give a more meaningful reading than the RS meter.
 I suspect that you are hitting at least 105db when applying more than 400watts. By the math based on the claimed sensitivity, 20watts should give you 96dB and 200watts should net you 105dB. Even allowing for a miss on the sensitivity, 200watts in should allow at least 96db continuous output without clipping.
There should also be a fairly sensitive SLP/RTA meter app available from iTunes.
Scotty

doubt 105 db , the maggies would be well into dynamic compression before then ....

a.wayne

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Re: 4bsst2 clipping with Maggie 1.7
« Reply #59 on: 31 Oct 2015, 07:14 pm »
I agree and disagree with this.  While moving up to bigger models of Maggies does improve the sound, a good amp and preamp will take your speakers to another level.  My going from the A21 to the Pass X250 was a major improvement.  And going from an AVA Ultra Plus tube preamp to a Pass X1 and then a BAT VK51se preamp was another major jump.  I then upgraded my DAC to a Luxman DA-06 which was the icing on the cake. I bought the BAT and Pass gear used at great savings.  Before upgrading my electronic's, I thought about upgrading to the Maggie 3.6's.  I think that I made the right decision as the 3.6's would not have sounded as good with my older gear.  I almost bought the 3.6's instead of the 1.6's and I had my wife's blessing but my electronics were not up to par at the time so I went with the 1.6's.

I do think that going from the MMG's to the 1.7's is a good place to start however.  I own a pair of MMG's and while they image a little better than my 1.6's, they certainly do not sound as good.

I am now at the point that I am considering upgrading to the 3.7's or possibly upgrading my amp to an X250.5 and my preamp to a BAT VK52se or VK32se.

Agree with all points, the A21 is very polite sounding , pretty soft to me, i bet a 3.7 would be fantastic with the Pass ...