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jfish
10-17-2004, 10:05 AM
i am running a set of small proac bookshelf speakers for my mains.
sometimes i run them in 2ch mode. if i turn it up (loud) to where they are clipping (speakers popping), is that the fault of the amp or the handling capasity of the speaker? reason i ask it when i listened to them in the store, they were louder but running off a $10,000 tube amp. so does clipping has more to do with the amp or speakers? the salesman lead me to believe it was the amp.....

i'm running a new digital sony es 2000 amp.

Sony str-da2000es
sony es amp 7.1
125wx7

proac tablette 8

Nominal Impedance
8 ohms
Recommended Amplifiers
10 to 100 watts
Frequency Response
40hz to 30Khz
Sensitivity
86db linear for 1 watt at 1 metre
Bass/Midrange
4 1/2" long throw cone design with linear low distortion motor system and raised suspension in
die cast chassis.
Tweeter
1" soft silk dome exclusive to ProAc with special surround and inner chamber

cam
10-17-2004, 10:28 AM
With the speakers popping, that would mean that the amps power has exceeded the speakers ability. When an amp clips your speakers will not pop but will sound like $hit because the amp has run out of current.

jfish
10-17-2004, 11:41 AM
so the amp isnt clipping, but the speakers have reached their limit. it was electronic music w/ some lower end, i guess the crossovers in the speakers go quite low..to the point where the 4" cone can be over driven.

no problem now i know not to play it loud in 2ch mode, it goes quiite loud with the sub active..and no problems
thanks

RGA
10-17-2004, 12:53 PM
Not so sure about this. Firstly you want to ignore largely the watts as rated by most amplifier makers especially receivers. I usually divide the receiver's rating by 5 to be on the safe side.

If another amplifier hooked up played LOUDER and you are absolutely sure the Tube amp played your spekaer louder - and Your Sony makes it pop then I would believe that to be the amp hard clipping. The reason I say this is also because you say you can play a lot louder with the Sub on. The Sub has it's own amp no? So this would mean that the Sony when only driveing the proac is having trouble more than likely with driving the bass on the proac. a LOT of speakers have an impedence drop to around 3ohms or lower at certain frequencuies - usually in the bass and some electrostats in the upper upper treble - both can be a diasaster for lesser amplifiers(and Receivers are lesser amplifiers).

Tube amps have a different tpe of clipping behavior - they are not a series of on/offs so they will not just STOP they will fuzz up the soundand try and drive what they can when being over driven. A lot of people often say that some very transparent tube amps are WARM. That is more than likely because the amp is being overdriven so the first thing the amp will have trouble with is what? The low impedence sections - usually deep bass and treble - so people say the bass is fat or wooley and the treble is rolled off. OF COURSE. the tube amp has run out of power. Some tube designs deliberately have that sound but that's something else again.

Take home a Bryston amplifier for a weekend - most dealers will let you try one. Don;t go nuts - you can still blow a speaker - but chances are youwill be able to play ouder with less distortion than with any receiver.

markw
10-17-2004, 01:36 PM
You can't reinvent the laws of physics. You simply ain't gonna geta heckuva lot of bass outta a standard 4 1/2" speaker no matter how much power you feed it.

hertz
10-18-2004, 02:26 AM
i am running a set of small proac bookshelf speakers for my mains.
sometimes i run them in 2ch mode. if i turn it up (loud) to where they are clipping (speakers popping), is that the fault of the amp or the handling capasity of the speaker? reason i ask it when i listened to them in the store, they were louder but running off a $10,000 tube amp. so does clipping has more to do with the amp or speakers? the salesman lead me to believe it was the amp.....

i'm running a new digital sony es 2000 amp.

Sony str-da2000es
sony es amp 7.1
125wx7

proac tablette 8

Nominal Impedance
8 ohms
Recommended Amplifiers
10 to 100 watts
Frequency Response
40hz to 30Khz
Sensitivity
86db linear for 1 watt at 1 metre
Bass/Midrange
4 1/2" long throw cone design with linear low distortion motor system and raised suspension in
die cast chassis.
Tweeter
1" soft silk dome exclusive to ProAc with special surround and inner chamber


I think it is your amp clipping.As RGA siad, spec sheets for mass audio amps are useless. MOst are not high current amps. I had similar problem couple of years back when I upgraded my japanese speakers to 86 db wharfadales. My 70 watt/ch pioneer integrated amp stared clipping and struggled to drive them. I tried my friend's sony ES reciever with almost the same result.The nakamichi and yamaha 100 watters I tried also struggled. Then I bought my NAD C350 Integrated and all my problems vanished.The nad is rated at 60 watts only. The DIFERENCE IS IN THE DESIGN.I would suggest you do a home demo of some decent amps.
Have fun

jfish
10-18-2004, 07:22 AM
thanks eveybody for the input.

i'm rethinking both my amp and speaker purchase.......

Kursun
10-18-2004, 10:29 AM
i am running a set of small proac bookshelf speakers for my mains.
sometimes i run them in 2ch mode. if i turn it up (loud) to where they are clipping (speakers popping), is that the fault of the amp or the handling capasity of the speaker? reason i ask it when i listened to them in the store, they were louder but running off a $10,000 tube amp. so does clipping has more to do with the amp or speakers? the salesman lead me to believe it was the amp.....

i'm running a new digital sony es 2000 amp.

Sony str-da2000es
sony es amp 7.1
125wx7

proac tablette 8

Nominal Impedance
8 ohms
Recommended Amplifiers
10 to 100 watts
Frequency Response
40hz to 30Khz
Sensitivity
86db linear for 1 watt at 1 metre
Bass/Midrange
4 1/2" long throw cone design with linear low distortion motor system and raised suspension in
die cast chassis.
Tweeter
1" soft silk dome exclusive to ProAc with special surround and inner chamberIt's clearly a case of woofer overloading. When experiencing clipping you don't hear popping. Just a un the verge of clipping you'll notice sound becoming brighter. Under heavy clipping the high frequencies will be heard as piercingly metallic. Popping indicates that the woofer cone has come to the limits of its travel and the cone stops are hitting the magnet.
I don't think you can compare the sound volume of your speakers performing in the store and your living room. A human ear is not a good SPL meter, aside having a poor memory for such things. Besides do you or the setup in the store utilise a subwoofer?

jfish
10-18-2004, 10:36 AM
It's clearly a case of woofer overloading. When experiencing clipping you don't hear popping. Just a un the verge of clipping you'll notice sound becoming brighter. Under heavy clipping the high frequencies will be heard as piercingly metallic. Popping indicates that the woofer cone has come to the limits of its travel and the cone stops are hitting the magnet.
I don't think you can compare the sound volume of your speakers performing in the store and your living room. A human ear is not a good SPL meter, aside having a poor memory for such things. Besides do you or the setup in the store utilise a subwoofer?

no they were in 2 ch. mode. i have been fooling with speakers about 10yrs and the basic answer usually is the correct one.

they lead me to believe the 4" woofer was made on supermans planet krypton. and couldnt be overpushed. sankeoil. no biggie they sound great with the sub on and the speakers crossed over.

Kursun
10-18-2004, 12:42 PM
no they were in 2 ch. mode. i have been fooling with speakers about 10yrs and the basic answer usually is the correct one.

they lead me to believe the 4" woofer was made on supermans planet krypton. and couldnt be overpushed. sankeoil. no biggie they sound great with the sub on and the speakers crossed over.
Some receivers do have their active crossovers on and output to the subwoofer even in 2-channel mode.
I do not like Sony home theater equipment in general, but I do respect their ES series equipment. I furthermore think that their ES equipment is much more sophisticated and more dependable than, uh... NAD equipment. I didn't have a chance to hear Proac speakers, but I know they are respactable. So what you have here is a fine system.

Your speakers' low sensitivity and limited power handling capabilities (especially at bass frequencies) may not suit the music material you listen. Selection of a higher crossover frequency will probably help a lot though. If you are pleased with the speakers at normal listening levels then this is all it counts. I would always prefer a system that sounds good at normal listening levels to a system that sounds good only at demo levels.

Woochifer
10-18-2004, 03:14 PM
It also has to do with the size of your room. If you listened to those speakers in a small demo room, and you have a large room with a high ceiling at home, then the amount of power needed to drive those speakers to the same volume increases a lot. Clipping is usually the amp, but speakers can also distort as they get closer to their physical limitations. With small speakers like yours, sending a full range signal can overwork the woofer and cause audible problems.

Sony has a history of monkeying around with their receiver specs, but the specs on your receiver are probably right because digital amps like yours typically measure well in their output. Where things get murky is more in the subjective areas of how good they sound, and the reliability of their digital drive amps. Up to this point, digital amps have proven popular with subwoofers, but have yet to really catch on with amps and receivers driving main speakers.

Tube amps sound audibly different from solid state amps. They have higher distortion and a subjectively fatter sound. They're also more compliant as you get closer to their output limits. They don't get harsh and grating like solid state amps will.

spacedeckman
10-22-2004, 09:04 PM
If you have adjustable Xover that works in 2 channel mode, play with it and you will play louder. You are trying to move too much air with too little woofer in a speaker not designed for it. Bottoming is a sure case of overdriving.

Wooch is right on the room size issue. Large rooms kill small speakers...no bass, no fill, sound thin and bright. That's why every speaker at Best Buy sounds like anus.

MikeyBC
10-23-2004, 09:40 AM
It sounds like the speaker reaching its limits. If the music sounds clean at the time you hear the pop its probably the voice coil of that tiny woofer hitting the back plate of the magnet assembly. Listen to the pop close, if its a sharp abrupt metallic pop its the speaker, if the popping you decribe is sloppy sounding then its the amplifier clipping.

Geoffcin
10-23-2004, 12:09 PM
i am running a set of small proac bookshelf speakers for my mains.
sometimes i run them in 2ch mode. if i turn it up (loud) to where they are clipping (speakers popping), is that the fault of the amp or the handling capasity of the speaker?

Are great speakers. I've always liked them, and have been toying with the idea of getting a pair for my computer audio system. That being said; they have a limit to the absolute SPL, especially in a larger room. The popping sound that you heard was the woofers hitting the limits. It has NOTHING to do with the amp used. Proacs are built very well, and there should be no damage to them, but you should make a note of the fact that that's as lound as they are going to go, at least with that amount of bass in the recording.
If you use a sub, then the lower octave or so will be handled by the sub, and you should not have the problem of the Proac's woofer being overdriven.

kfalls
10-25-2004, 05:42 AM
Proacs are very well respected speakers. They're a more respected name in speakers than Sony is in receivers. Actually Sony receivers are notorious for underpowering their power supplies, especially in their AV receivers. I work in Terre Haute IN, where Sony has a CD manufacturing facility. They also have an outlet store where they sell reduced priced (A and B stock) Sony electronics. A friend who works for them tells me their receivers are always coming in broken. Usually what happens is they blow the rear speakers during loud passages such as explosions. The increased loudness sucks the power supply dry effectively putting DC across the speakers.

If you've ever experienced crossing the cables jumping a car, or experimented as a kid with dry cell batteries and noticed the wire gets hot when connected from + to - you understand how speakers "blow". During clipping the tops of a normal analogue signal is cutoff, effectively placing DC across the coil of the speaker. The more the amp is overdriven the wider the base of the signal and amount of DC. The coil heats, and if enough current is provided, bottoms the speakers to its limits in the direction of polarity. Eventually the coil heats to a point the wire opens (just like an expensive fuse) and the speaker is blown. On a blown speaker you can usually hear a scratching sound when moving the cone in and out, this is the sound of the open wire scratching the sides. Although an 86db efficiency isn't a terrible load for a receiver, I would never attempt to power a Proac from a Sony, not even their higher-end series (I believe they call it their ES Series). So to answer the question about if it's the speaker or amp clipping, it's both, but the amp clipping is the cause and the speaker bottoming to its limits is the effect caused by the amp.

Kursun
10-25-2004, 08:09 AM
A friend who works for them tells me their receivers are always coming in broken. Usually what happens is they blow the rear speakers during loud passages such as explosions.A clipped amplifier does not come in broken. The tweeter of the speaker system gets damaged.


Although an 86db efficiency isn't a terrible load for a receiver, I would never attempt to power a Proac from a Sony, not even their higher-end series (I believe they call it their ES Series).While I agree with you on your remarks about run-of-the-mill Sony HT equipment, You seem to be highly misinformed about their ES series (you seem to be not even sure what they are called). They are a completely different breed. Sony has produced some of the finest high-end 2-channel equipment during the 90's under the ES series line. Most have been highly acclaimed by even the most conservative British audio press. I have used some. They are very fine equipment indeed. I would prefer a Sony ES anytime over, let's say... NAD equipment. The internet forums are flooded with NAD owners seeking help for their faulty equipment.

entwistle101
11-02-2004, 05:56 AM
When an amp clips it does in fact chop the top of the wave form off, however this does not effecetivly place DC across the speakers what it does is effectivly place a virtual square wave across the speakers. A square wave contains a lot of high frequency content which will easily blow your tweeters.

I would say that your amp might not have the power to drive your speakers. Speaker loads are dynamic (constantly changing), they are also complex ie the voltage and current can be out of phase (not in line with each other) this means that the amp has to work very hard in order to produce the required output. If your amp isn't up to it it'll just clip which is probably what you're hearing.

I sugest you try out another amp before geting rid of the speakers!

I've been using a NAD C350 for 3 years now and have had no problems. NAD amps are well known for being good at handling tricky speaker loads I would suject you give them a try.

Ste

Richard Greene
11-03-2004, 09:58 AM
When an amp clips it does in fact chop the top of the wave form off, however this does not effecetivly place DC across the speakers what it does is effectivly place a virtual square wave across the speakers. A square wave contains a lot of high frequency content which will easily blow your tweeters.
RG
A severely clipped 100 Hz. sinewave, clipped enough to resemble a 100Hz. square wave, will result in less than one watt of clipping harmonics reaching a tweeter through a 2000Hz.
12dB/octave high-pass filter. Probably more like 0.5 watts of treble harmonics.
Far from enough power input to damage a tweeter voice coil.

The more common intermittent clipping of music transients such as bass drum hits or snare drum hits, would add small amounts of treble clipping harmonics intermittently.

Clipped music transients are unlikely to create treble clipping harmonics whose power is more than one watt, and then only intermittently. Any more would drive listeners out of the room. No tweeter voice coil will be damaged from less than one watt of intermittent or even continuous clipping harmonics.

Tweeter voice coils are damaged by too much electricity (treble too loud for too long).
Amplifier clipping adds some treble without one touching the pre-amp volume control,
so it adds to the heat load of the tweeter's voice coil.

However using a much more powerful amplifier that never clips would only allow you to play music roughly 2dB louder for the same tweeter voice coil heating as an amplifier that clipped intermittently. 2dB is a barely audible SPL increase. Not that anyone wants to listen to intermittent amplifier clipping ... but intermittent clipping is often overlooked or blamed on bad recordings or harsh speakers ... until a tweeter dies -- then audiophiles and salesmen gather around the dead tweeter and declare without a doubt that the amplifier did not have enough power ... and a new more expensive and more powerful amplifier is the only answer to prevent tweeter damage. This is an urban myth ,,, but audio salesmen love it !

kfalls
11-04-2004, 06:10 AM
Thanks Richard for the clarification. I'm embarassed to have fallen subject to the urban legend, but your explanation makes perfect sense.

If not from distortion from an underpowered amp, then what might be the culprit for blown tweeters, or woofers? Are you stating it's no more likely to blow drivers using an underpowered amp than an adequate or overpowered amp? I understand specs are best guesstimations and music and impedances fluctuate continuously, so where does the heat come from that burns voice coils when powered within their specs? With ferro fluids, vented poles, Kapton formers and heatsinks out the wazoo as part of higher-end designs (and many car subs), why is there such a concern about heat? Why did Telarc put a disclaimer on their 1812 Overture CD warning of high decibel levels and possible damage to equipment? I'm not questioning your response, on the contrary I appreciate it, after learning this is an urban legend I want to be informed so as not to propogate mis-information.

I've read a lot of reviews and understand much of what I read about speaker design, but never designed one, or discussed design with those who have. There's always going to be gaps or misunderstanding when reading is the only source, thats why we have teachers. While you're on this subject I'd like to pick your brain, if you don't mind. I've read and respected your posts in the past.

Richard Greene
11-04-2004, 10:20 AM
The amplifier used is a minor issue.

Speakers are damaged by the last person who touched the volume control.

It's that simple.

There's a coil of wire and electricity.

Too much electricity and a tweeter's coil of wire is damaged.

Woofers and mid-range drivers are usually damaged from overexcursion ...
or from voice coil overheating

Clipping harmonics add a small amount of treble output (odd-order distortion) without one touching the volume control.

A non-clipping amp playing a few dB louder will cause the same voice coil temperature.

See here why some Telarc discs are "dangerous" (really low bass frequencies)
http://www.pcavtech.com/abx/basscds.htm