Studio monitors?

[Docbop]

I remember when I first got to hang at recording studios and seemed like they all had Altec 604e monitors or the alternative Urei Time Aligned Studio Monitors that were basically a clone of the 604e coaxial speakers.  Then I got my jor at Sound City and it was the first time hearing Tannoy studio monitors those were great.  

[stoken6]

10 hours ago, TJ Cornish said:

Which version was used with the toilet paper over the tweeters?

That was the ultra-desirable limited-edition variant!

 

Cheers ,Mike.

[GRollins]

I've spent many, many years in hifi audio and could yammer on at length about the uses and abuses of mid-fi to high end speakers for live instruments. I'm short on time (today is sheerock...and I hate sheetrock...by suppertime tonight I will be in a truly foul humor) and will limit myself to saying:

 

1) Yes, you can use home stereo speakers in a studio setting.

2) I would recommend decent mid-fi speakers, never lo-fi, and usually not high end.

3) As a general rule, stereo speakers will have lower distortion, but...

4) Will not play as loud, and...

5) May or may not handle transients well. (This will vary widely from speaker to speaker.)

6) "Pro" speakers can reach ear-crushing volumes. DO NOT try this with stereo speakers. You need to be honest with yourself about what volume levels you intend to strive for. If you want "live" 120dB levels, go with pro studio monitors, not stereo speakers. Me? I want to keep my hearing intact. I play at lower volumes these days.

7) I have a range of speakers available...some very, very nice. Know what I use for my studio? My venerable old ADS 300C speakers from back in the day, with subs...they're damned near perfect for what I do. NOTE: I do not play loud. If I were to do so, I would pull out different speakers. The ADS 300 series were available in different formats--a bookshelf speaker (300), a version with a mounting clamp (the ones I'm using...very convenient for my layout)(300C), a flat, open-backed version for mounting in the rear deck of a car (300i...NOT recommended for this application). Maybe others that I'm not remembering. There were also different generations, but that's going to be going rather far afield.

8 ) ADS had other speakers, some downright huge, that were used in various applications, including pro studios (Telarc used ADS monitors. Not sure about which model...2030s?) Although some would argue that ADS was a high end company, in my book they're just mid-fi. For my money, the best speaker in their lineup was the early 710...no, not the 810, the 710. I'd use them instead of my 300s if I had room. The best speaker they ever made.

--Not a fan of this auto-format thing where I'm try to make #8 on a list and it's insisting on turning it into a sunny, cool emoji...that's why this entry has a space and the others don't--

9) PAY ATTENTION, THIS IS IMPORTANT: You can use speakers of any sort with more power than they're rated for. The critical thing is never to let an amp clip. EVER. It's clipping that kills speakers, not (usually) power, per se. When a waveform clips, it begins to approximate a square wave. The cone lurches forward, then sits there. Current is flowing through the voice coil, but the cone isn't moving. Dynamic drivers are air-cooled devices and if they're not moving, air isn't flowing past the voice coil and they're not cooling. Heat builds up rapidly and the coil former (plastics or synthetics--metal formers will be okay) will melt or the adhesive (anything from shellac to epoxies) used to hold the voice coil windings in place will melt, then burn. Likewise the insulation on the wire on the voice coil. In extreme cases the wire itself melts. As long as the cone is moving freely the driver can cool. When I was toiling in the audio fields and someone burned up speakers, I'd sit 'em down and have a talk, then sell them a bigger amp...not bigger speakers. More speakers die from too-small amps than too-big amps, by a 10:1 ratio.

10) Woofers are susceptible to over excursion on transients. How well a stereo speaker will handle this varies--some do, some don't. Here's where you run into people screaming not to use stereo speakers in a studio. They bottomed the woofer; the voice coil slams against the back plate of the magnet structure. This sounds like shit (loud, clattering noise) and very quickly destroys the voice coil. Or the surround on the cone rips. Options: Use a subwoofer to take up the lower octaves or try a different speaker. Yes, this is sorta #5 again, just in a little more detail.

11) It's not a bad idea to use a compressor to lower the transients, especially for higher volumes. Combined with a sub, a compressor will let you get away with murder.

12) If you go with mid-fi speakers (ADS or other), try an assortment. They have a strong tendency to have bumped-up bass (technically the woofer's Q will be over 0.707, sometimes by ridiculous margins) right before the low end rolloff. My Rogers LS3/5a's are a good example. They were specifically designed as monitors for the BBC. Bump, but very well handled. Lovely speakers. No, you're not going to find LS3/5a's for pennies on the dollar--look for the ADS. The ADS 200 variants were too small. Skip those. The 300 or maybe 400s (the ones with the larger cabinets) would be good bets. Then jump to the 710. After that, you're into models that will require help moving and start taking up floor space. Your call. If you've got a speaker (of any sort) with a bass hump, use your active crossover to tune it out; set the crossover point above the bump.

 

I need to move on. Good luck.

 

Grey

[TJ Cornish]

3 hours ago, GRollins said:

 

9) PAY ATTENTION, THIS IS IMPORTANT: You can use speakers of any sort with more power than they're rated for. The critical thing is never to let an amp clip. EVER. It's clipping that kills speakers, not (usually) power, per se. When a waveform clips, it begins to approximate a square wave. The cone lurches forward, then sits there. Current is flowing through the voice coil, but the cone isn't moving. Dynamic drivers are air-cooled devices and if they're not moving, air isn't flowing past the voice coil and they're not cooling. Heat builds up rapidly and the coil former (plastics or synthetics--metal formers will be okay) will melt or the adhesive (anything from shellac to epoxies) used to hold the voice coil windings in place will melt, then burn. Likewise the insulation on the wire on the voice coil. In extreme cases the wire itself melts. As long as the cone is moving freely the driver can cool. When I was toiling in the audio fields and someone burned up speakers, I'd sit 'em down and have a talk, then sell them a bigger amp...not bigger speakers. More speakers die from too-small amps than too-big amps, by a 10:1 ratio.

 

This is not accurate. The shape of the wave does not automatically harm a driver - heck - every synth on the planet uses square waves as an oscillator source. The issue, as you point out, is power handling. Square waves - at least in units of time relevant for audio (at some point a square wave at very low frequency is essentially DC and can indeed be power dissipation without cooling from movement) are composed of not a single frequency, but the fundamental plus odd harmonics. In fact, your speaker’s ability to reproduce close to a square wave indicates excellent transient response and high frequency resolution, which is desirable and contributes to fidelity.

 

Clipping of an amp - either the power amp or a preamp - can be an issue because high frequency content is generated by the clipping which wasn’t there in the original signal (those new odd harmonics), which can increase power sent to a band where a driver is less capable of handling that power - the HF driver. Even in this case, though, the issue is power handling, not the shape of the wave.

 

The ‘I’d sell them a bigger amp, not bigger speakers’ is a pet fallacy of mine - anyone who is unhappy with the performance of their setup such that they run them into clipping will not be happy with a larger amp that may buy them a couple of dB worth of less distorted sound; they will just run the larger amp into clipping too, and destroy those too-small speakers even faster.

[GRollins]

TJ Cornish,

We are in agreement. Fourier analysis breaks a square wave down into a succession of sine wave harmonics. But...you're missing the point that that's true for any repetitive waveform, triangles, sawtooths, etc. (Smart guy, that Jean-Baptiste...) Yet it's square waves (i.e. clipping) that are fatal, not triangles, et. al.

 

Curious, that...

 

Amps don't clip in sine, triangle, ramp, or sawtooth waveforms, they clip in square waves (once you push 'em hard enough).

 

Your statement about bigger amps being a pet fallacy makes no sense. "...Anyone who is unhappy with the performance of their setup such that they run them into clipping..." So you're saying that people who are unhappy with the sound of their system...what?...they think higher volume will make it sound better? This, I don't understand. I don't know about people in St. Louis, but over here in the Carolinas, people tend to crank their volume knobs for the exact opposite reason. They like what they hear and want more of the same. They're not running their gear into clipping because they don't like what they hear. I am completely at a loss to understand why anyone would do as you describe.

 

Note also that your statement about tweeters being least able to handle power flies in the face of reality. Go to, say, Parts Express or Madisound and look at the wattage ratings for tweeters. If you've got a tweeter that's rated for 90W (ScanSpeak Classic D2010/852100, chosen at random, but a decent tweeter, for all that), the entire output of a 100W amp would not be sufficient to blow the tweeter...if your position was correct. Remember, subtract passive losses through the crossover (quite a bit, actually--consider that 10W and 20W resistors are common in crossovers, and it's not just to say "my resistor is bigger than your resistor"), also subtract the power represented by the fundamental and lower harmonics of the waveform, which will be handled by the woofer and/or midrange. Note, per Fourier analysis, that the fundamental is going to be far, far larger in amplitude than any harmonics routed to the tweeter. Yet, I guarantee you a 100W amp will fry a tweeter rated for any wattage you care to throw into the fray. How can a, let's say, 20W signal (after crossover insertion losses and the signals powering the woofer and midrange) destroy a tweeter if it's rated for 90W? Or even 50W? If it's only a matter of the power rating of the tweeter, as you claim, then you've got some 'splaining to do.

 

Besides, you've already admitted that I'm right: "Square waves - at least in units of time relevant for audio (at some point a square wave at very low frequency is essentially DC and can indeed be power dissipation without cooling from movement)..." Note that square waves don't have to be 'at a very low frequency' to be harmful. Consider heat dissipation in computer CPUs, for instance. Lotsa heat. Very high frequencies. But at this point we're going to get off into duty cycles and such and I'm out of time.

 

Just sit and think it through, you're already most of the way there.

 

Grey

[jazzpiano88]

9 hours ago, GRollins said:

I've spent many, many years in hifi audio and could yammer on at length about the uses and abuses of mid-fi to high end speakers for live instruments. I'm short on time (today is sheerock...and I hate sheetrock...by suppertime tonight I will be in a truly foul humor) and will limit myself to saying:

 

1) Yes, you can use home stereo speakers in a studio setting.

 

Shaking head vigorously in agreement.

 

I used to use PA speakers and power amps with mixer for home studio and audio reproduction.

Regarding the latter, boy could you overdo things putting on Aja and blasting your ears out in pure hi-fidelity

You could feel like the sound pro at the club testing out their system before the band set up.

 

Since then I'm really really happy with the high end home stereo approach.  

The Klipsch Cornwall III's satisfy everything you point out as caveats.     The one thing you can't do is set anything on top of them that will move. 

 

[TJ Cornish]

2 hours ago, GRollins said:

TJ Cornish,

We are in agreement. Fourier analysis breaks a square wave down into a succession of sine wave harmonics. But...you're missing the point that that's true for any repetitive waveform, triangles, sawtooths, etc. (Smart guy, that Jean-Baptiste...) Yet it's square waves (i.e. clipping) that are fatal, not triangles, et. al.

 

Curious, that...

 

Amps don't clip in sine, triangle, ramp, or sawtooth waveforms, they clip in square waves (once you push 'em hard enough).

 

Your statement about bigger amps being a pet fallacy makes no sense. "...Anyone who is unhappy with the performance of their setup such that they run them into clipping..." So you're saying that people who are unhappy with the sound of their system...what?...they think higher volume will make it sound better? This, I don't understand. I don't know about people in St. Louis, but over here in the Carolinas, people tend to crank their volume knobs for the exact opposite reason. They like what they hear and want more of the same. They're not running their gear into clipping because they don't like what they hear. I am completely at a loss to understand why anyone would do as you describe.

 

Note also that your statement about tweeters being least able to handle power flies in the face of reality. Go to, say, Parts Express or Madisound and look at the wattage ratings for tweeters. If you've got a tweeter that's rated for 90W (ScanSpeak Classic D2010/852100, chosen at random, but a decent tweeter, for all that), the entire output of a 100W amp would not be sufficient to blow the tweeter...if your position was correct. Remember, subtract passive losses through the crossover (quite a bit, actually--consider that 10W and 20W resistors are common in crossovers, and it's not just to say "my resistor is bigger than your resistor"), also subtract the power represented by the fundamental and lower harmonics of the waveform, which will be handled by the woofer and/or midrange. Note, per Fourier analysis, that the fundamental is going to be far, far larger in amplitude than any harmonics routed to the tweeter. Yet, I guarantee you a 100W amp will fry a tweeter rated for any wattage you care to throw into the fray. How can a, let's say, 20W signal (after crossover insertion losses and the signals powering the woofer and midrange) destroy a tweeter if it's rated for 90W? Or even 50W? If it's only a matter of the power rating of the tweeter, as you claim, then you've got some 'splaining to do.

 

Besides, you've already admitted that I'm right: "Square waves - at least in units of time relevant for audio (at some point a square wave at very low frequency is essentially DC and can indeed be power dissipation without cooling from movement)..." Note that square waves don't have to be 'at a very low frequency' to be harmful. Consider heat dissipation in computer CPUs, for instance. Lotsa heat. Very high frequencies. But at this point we're going to get off into duty cycles and such and I'm out of time.

 

Just sit and think it through, you're already most of the way there.

 

Grey

 

Grey, you admit that it is ultimately power consumption that damages speakers, but you indicate that shape of the wave matters. You are incorrect; a triangle wave of equivalent power (area under the curve) to a square wave at any frequency you care to examine will have the same heating power, and the same destructive potential. The same is true for whatever shape wave you want to consider. An amp driven into clipping puts out more energy than an amp not driven into clipping (up to 3dB more, AKA 2X the watts), but a larger amp putting out the equivalent SPL of your clipped amp will have similar heating power to the clipped amp, with the main difference being that the extra energy of the clipped amp is in the form of HF signal, which puts HF drivers at risk.

 

I have significant experience in professional sound reinforcement and I have owned many amplifiers capable of putting out 4000 watts into a 4Ω load and speakers that have matching capability. Your hypothetical 90W high frequency driver would typically be paired with a 2000W low frequency driver. It takes much more energy to reproduce low frequencies than high frequencies. If the speaker you are considering has a 90W HF driver and a 90W LF driver then I guess you would be correct that in that instance you would be unlikely to blow a HF driver with a 100W amp, but I have never seen a speaker built that way because it doesn’t make sense. Doing a quick look on Sweetwater, the typical studio monitor has something like a 5:1 power ratio of LF:HF. 

 

As to the LF driver’s experience being sent a square wave - if like some cheap speakers the LF driver gets the full range signal and the HF is run with just a HPF, then yes, the LF driver theoretically gets the whole square wave, but the corners of the square wave - the part that is different from a sine wave, are small in magnitude and don’t contribute significantly to heating. If your speaker has a better crossover that contains both a HPF for the HF driver and a LPF driver for the LF driver, then the LF driver doesn’t even see the square wave; it sees a sine wave with a slightly flatter top - the flattening due to the harmonics the driver gets below the crossover frequency. I agree there is a duty cycle factor here, but as I stated above, a larger amp driven to the same apparent volume will have the same duty cycle issues on the LF side, but the extra energy goes to the HF driver, not the LF driver.

 

RE our hypothetical friends with too small speakers plus a too big amp - it takes double the electrical watts to get just 3dBSPL more output. Maybe some of your friends live in that knife-edge area where that 3dB is the difference between not enough and just right, but in my not insignificant experience, I find that if the user is unhappy with whatever volume their rig can make pre-clipping, the barely discernible difference of the extra 3dB that twice the amp would make isn’t going to cut it. Making them happy means significantly more output - usually 6dB (4x the watts) or more. That’s definitely going to require different speakers.

 

The best thing that has happened in the last 20 years is multi-amped speakers with electronic crossovers, time alignment, internal limiting, and the whole ball of wax making them relatively plug and play. All of the above is trivia from another age for 99% of speaker users.

 

Please leave your condescension at home.

 

Thanks.

[jazzpiano88]

22 minutes ago, TJ Cornish said:

Grey, you admit that it is ultimately power consumption that damages speakers, but you indicate that shape of the wave matters.

 

I think what Grey is getting at is not the short term frequency content that is described by a short term time interval in frequency space that you are talking about. 

 

He is talking about clipping duty cycles of time durations that destroy speakers due to DC current.  A synth square wave has a duty cycle of no-where near the energy needed to destroy a speaker at audio frequencies.   

[TJ Cornish]

1 minute ago, jazzpiano88 said:

 

I think what Grey is getting at is not the short term frequency content that is described by a short term time interval in frequency space that you are talking about. 

 

He is talking about clipping duty cycles of time durations that destroy speakers due to DC current.  A synth square wave has a duty cycle of no-where near the energy needed to destroy a speaker at audio frequencies.   

There are very few amplifiers that can produce a DC signal long enough in duration to do damage to a speaker. There were some 1970’s era amps that had this issue (and issue is the right word for it - no amp should be able to do this); virtually every amp made in the last year has a HPF of 20Hz or so that will prevent this from happening, unless the amp is damaged.

[jazzpiano88]

11 minutes ago, TJ Cornish said:

There are very few amplifiers that can produce a DC signal long enough in duration to do damage to a speaker. There were some 1970’s era amps that had this issue (and issue is the right word for it - no amp should be able to do this); virtually every amp made in the last year has a HPF of 20Hz or so that will prevent this from happening, unless the amp is damaged.

 

If you say every amp is protected in the last year, I'll grant you that since I have no info otherwise.     Do you have an address I can send you my defective NAD 3020 since you seem to be indemnifying the industry retroactively 😆

[TJ Cornish]

39 minutes ago, jazzpiano88 said:

 

If you say every amp is protected in the last year, I'll grant you that since I have no info otherwise.     Do you have an address I can send you my defective NAD 3020 since you seem to be indemnifying the industry retroactively 😆

Your NAD amp appears to have been produced in the 1970’s and predates my experience in audio; however according to Wikipedia, even your NAD amp seems to have a high pass filter, as the frequency range is listed as 10Hz on the low end. If you send me your amp I will gladly recycle it for you and suggest you get some kind of modern monitor with internal DSP, multiple amp channels, and limiting.

[UnderGroundGr]

I have Genelec 8030A for almost 15 years, excellent studio monitors!

[GRollins]

14 hours ago, TJ Cornish said:

 

Grey, you admit that it is ultimately power consumption that damages speakers, but you indicate that shape of the wave matters. You are incorrect; a triangle wave of equivalent power (area under the curve) to a square wave at any frequency you care to examine will have the same heating power, and the same destructive potential. The same is true for whatever shape wave you want to consider. An amp driven into clipping puts out more energy than an amp not driven into clipping (up to 3dB more, AKA 2X the watts), but a larger amp putting out the equivalent SPL of your clipped amp will have similar heating power to the clipped amp, with the main difference being that the extra energy of the clipped amp is in the form of HF signal, which puts HF drivers at risk.

 

I have significant experience in professional sound reinforcement and I have owned many amplifiers capable of putting out 4000 watts into a 4Ω load and speakers that have matching capability. Your hypothetical 90W high frequency driver would typically be paired with a 2000W low frequency driver. It takes much more energy to reproduce low frequencies than high frequencies. If the speaker you are considering has a 90W HF driver and a 90W LF driver then I guess you would be correct that in that instance you would be unlikely to blow a HF driver with a 100W amp, but I have never seen a speaker built that way because it doesn’t make sense. Doing a quick look on Sweetwater, the typical studio monitor has something like a 5:1 power ratio of LF:HF. 

 

As to the LF driver’s experience being sent a square wave - if like some cheap speakers the LF driver gets the full range signal and the HF is run with just a HPF, then yes, the LF driver theoretically gets the whole square wave, but the corners of the square wave - the part that is different from a sine wave, are small in magnitude and don’t contribute significantly to heating. If your speaker has a better crossover that contains both a HPF for the HF driver and a LPF driver for the LF driver, then the LF driver doesn’t even see the square wave; it sees a sine wave with a slightly flatter top - the flattening due to the harmonics the driver gets below the crossover frequency. I agree there is a duty cycle factor here, but as I stated above, a larger amp driven to the same apparent volume will have the same duty cycle issues on the LF side, but the extra energy goes to the HF driver, not the LF driver.

 

RE our hypothetical friends with too small speakers plus a too big amp - it takes double the electrical watts to get just 3dBSPL more output. Maybe some of your friends live in that knife-edge area where that 3dB is the difference between not enough and just right, but in my not insignificant experience, I find that if the user is unhappy with whatever volume their rig can make pre-clipping, the barely discernible difference of the extra 3dB that twice the amp would make isn’t going to cut it. Making them happy means significantly more output - usually 6dB (4x the watts) or more. That’s definitely going to require different speakers.

 

The best thing that has happened in the last 20 years is multi-amped speakers with electronic crossovers, time alignment, internal limiting, and the whole ball of wax making them relatively plug and play. All of the above is trivia from another age for 99% of speaker users.

 

Please leave your condescension at home.

 

Thanks.

 

It's like Nelson Pass once said to me: "Music is part of the entertainment industry. Some people just happen to get their entertainment value out of arguing about it." I'd never thought about it in those terms, but...yeah...he's right.

 

Your post is largely nonsense. I don't have the time (or the energy, frankly) to deconstruct all the errors, but I'll take an easy one right off the top...your very first paragraph. This isn't about the heat delivered to the load by the signal (regardless of waveform), it's about the load's ability to dissipate that heat. It just happens that square waves have this unique thing where the cone lurches forwards (or backwards) and sits there, unlike sine, triangle, or other waveforms, which are always in motion. Until you understand that distinction, you'll go nowhere, fast. It's easiest to visualize with a woofer because you can see the cone move and you can look at the spider and see that it's an open mesh that air can pass through. As the cone moves, it pumps air past the voice coil, cooling it (clever trick, eh?). If the cone is sitting still, reproducing a square(ish) wave, it's not pumping air and the voice coil isn't cooling. Heat builds up. Driver dies. The same is true for mids and tweeters. You just have to trace the heat dissipation. It's that simple.

 

...or...apparently, that hard...

 

For homework, take a battery and apply it to a woofer as a crude approximation of (half of) a square wave. The cone jumps, then sits. Yet the heat doesn't stop just because the cone is sitting still--the full current is still flowing, creating heat in the voice coil. Now, a D-cell isn't going to do a decent sized woofer any harm because there's not enough current available (an 8 Ohm driver would be facing a terrifying 0.28W or so...do not use a car battery!). This is just a visualization aid. But the same principle holds true at higher signal levels. Lurch, sit, get hot. Lurch back the other way, sit, get hotter. The ventilation represented by the lurch isn't proportionate to the heat buildup. Ventilation falls behind heat production. Heat reaches the point where the driver fails. Simple. Bad...but simple.

 

And if I'm reading your post correctly--maybe there's something I'm missing (man, I hope so, because this is just weird)--you're still arguing that people who are unhappy with the sound turn up the volume in a doomed attempt to make things sound better...?

 

Huh? What?

 

I repeat, it's not about volume, per se, it's about heat dissipation. Focus on the heat buildup, not the volume. Heat is the enemy.

 

Oh, well...argue away, if that's your entertainment value. I'll go along for a little while longer, but will reach a saturation point soon. Until you've actually thought this through, there's not going to be a lot more to be said.

 

Back to work--plumbing (done, thankfully) and more sheetrock (ugh)...

 

Grey

[TJ Cornish]

1 hour ago, GRollins said:

 

It's like Nelson Pass once said to me: "Music is part of the entertainment industry. Some people just happen to get their entertainment value out of arguing about it." I'd never thought about it in those terms, but...yeah...he's right.

 

Your post is largely nonsense. I don't have the time (or the energy, frankly) to deconstruct all the errors, but I'll take an easy one right off the top...your very first paragraph. This isn't about the heat delivered to the load by the signal (regardless of waveform), it's about the load's ability to dissipate that heat. It just happens that square waves have this unique thing where the cone lurches forwards (or backwards) and sits there, unlike sine, triangle, or other waveforms, which are always in motion. Until you understand that distinction, you'll go nowhere, fast. It's easiest to visualize with a woofer because you can see the cone move and you can look at the spider and see that it's an open mesh that air can pass through. As the cone moves, it pumps air past the voice coil, cooling it (clever trick, eh?). If the cone is sitting still, reproducing a square(ish) wave, it's not pumping air and the voice coil isn't cooling. Heat builds up. Driver dies. The same is true for mids and tweeters. You just have to trace the heat dissipation. It's that simple.

 

...or...apparently, that hard...

 

For homework, take a battery and apply it to a woofer as a crude approximation of (half of) a square wave. The cone jumps, then sits. Yet the heat doesn't stop just because the cone is sitting still--the full current is still flowing, creating heat in the voice coil. Now, a D-cell isn't going to do a decent sized woofer any harm because there's not enough current available (an 8 Ohm driver would be facing a terrifying 0.28W or so...do not use a car battery!). This is just a visualization aid. But the same principle holds true at higher signal levels. Lurch, sit, get hot. Lurch back the other way, sit, get hotter. The ventilation represented by the lurch isn't proportionate to the heat buildup. Ventilation falls behind heat production. Heat reaches the point where the driver fails. Simple. Bad...but simple.

 

And if I'm reading your post correctly--maybe there's something I'm missing (man, I hope so, because this is just weird)--you're still arguing that people who are unhappy with the sound turn up the volume in a doomed attempt to make things sound better...?

 

Huh? What?

 

I repeat, it's not about volume, per se, it's about heat dissipation. Focus on the heat buildup, not the volume. Heat is the enemy.

 

Oh, well...argue away, if that's your entertainment value. I'll go along for a little while longer, but will reach a saturation point soon. Until you've actually thought this through, there's not going to be a lot more to be said.

 

Back to work--plumbing (done, thankfully) and more sheetrock (ugh)...

 

Grey

lol. You can repeat your misunderstanding as many times as you want to; it’s still not correct.

 

First of all, your amp doesn’t make DC. I don’t care what happens with a battery and a speaker; that’s not what happens with an amp. ALL AMPS THAT ARE NOT BROKEN HAVE A HIGH PASS FILTER AND DO NOT PASS DC. DC has never been useful to the production of sound; it robs power handling with no acoustic benefit. I won’t argue this with you; check any spec sheet, go ahead and try to get your amp to do this - send a DC signal in, plug your driver on the output, watch what happens. Your voice coil will move in whatever direction it moves relative to polarity of the input, then it will settle back to its resting position because the amp’s high pass filter filters out the DC.

 

Secondly, the waveform of the signal does not directly translate to the position of the driver. It is an accelerating force in one direction or the other. Your driver has mass. It takes time to get where it is going. Once it gets to where the signal tells it to go, it doesn’t stop; it keeps ringing due to the springiness of the assembly. How much depends on materials, the size of the driver, damping factor of the amp, etc.

 

Hoping for the best that you agree with me thus far, we are now left to the thought experiment of a tiny slice of time where the signal on a square wave is flat. We will consider JazzPiano88’s NAD amp with a high pass filter of 10Hz (this seems to be lower than many; 20Hz is probably more common), so the maximum amount of time a theoretical driver could be held in position is 1/2 the period of the low-pass value of 10Hz, which is 1/20th of a second, or 50 milliseconds. This means that your driver is still fanning itself at full travel 20 times per second, even when sent a worst case square wave.

 

The issue is and has always been about the power handling of the driver, not the shape of the waveform, and not that the driver “hangs out at full travel positions and heats without moving”. I know we both agree that clipping is bad. 

 

I have already explained where the extra energy of a clipped waveform goes - to higher harmonics. This is why adding any distortion effect always brightens the sound. It does not and cannot make the fundamental frequency louder. Whether this actually causes damage depends on the power handling of the driver in question. You can put your 100w amp in full square wave at the frequency of choice in one of my 4000w speakers and it will be annoying, but not cause any damage. Conversely, your 100W amp operating at below clip into a 10W driver may be death.

 

For hopefully the last time to our friend seeking more volume:

 

1. We assume that our friend has an amp such that at program power (1/8 peak power handling, which equates to typical music just at the point of clipping) for a certain style of music that our friend wants to listen to it is perfectly matched to the power handling of our friend’s speaker.

 

2. We assume that this person is not happy with the level they are achieving with their existing amp; otherwise they would not be seeking to turn it up.

 

3. Our theoretical amp if driven to extreme clipping (1/3 power handling) can produce 2X the electrical power compared to an unclipped signal, which in a perfect world would produce 3dBSPL more sound, with that additional energy being in the form of harmonics. In reality, our non-ideal speaker is probably entering power compression, where you get less additional output per input due to the impedance of the coil increasing due to heat. 

 

4. We both agree that clipping is bad, and discourage our friend from doing that. We take divergent paths.

 

- You tell him to go buy an amp 2X the size of his original amp so that Mr. Friend can get his additional sound out, and hopefully become happy, because you tell him the root issue is clipping of his amp, and not power handling of his speaker. Mr. Friend now operates his new amp just before the point of clipping. Mr. Friend’s speaker is now receiving twice the power input as it was previously which has to be dissipated by heat, and the result of this additional energy is at best 3dBSPL more, but is likely less due to power compression. This new energy- even if it doesn’t immediately blow something up, will shorten the life of the speaker.

 

- I tell him that his speakers are inadequate and his choices are to either be disciplined and not run his amp into clipping, or go buy speakers that are more capable with appropriate amplification that can meet Mr. Friend’s need for SPL with enough headroom so Mr. Friend won’t be tempted to drive his amp to clipping.

 

Your scenario can work on the margin - it is probably possible to get slightly more usable output from a given speaker with an amp slightly oversized (note that is an extreme simplification - it is very difficult to model speaker capacity as musical content varies widely, and even things like ambient temperature of the room can have a material effect). However, I don’t believe this works in the real world. Anyone tempted to turn up an amp already on the verge of clipping will not be satisfied with maybe 2dB more output; all you are doing is giving them a bigger heater with which to cook their speakers.

 

[jazzpiano88]

15 hours ago, TJ Cornish said:

Your NAD amp appears to have been produced in the 1970’s and predates my experience in audio; however according to Wikipedia, even your NAD amp seems to have a high pass filter, as the frequency range is listed as 10Hz on the low end. If you send me your amp I will gladly recycle it for you and suggest you get some kind of modern monitor with internal DSP, multiple amp channels, and limiting.

That may have been the spec, but DC was getting into the output as you could clearly see in the speaker cone movement.

 

Anyway, there are high end amplifiers that specifically designed to drive very low impudences down to almost DC.
Audio Research had these massive monoblocks designed to meet distortion specs into 1 ohm and 2 Hz!    They are said to drive happily drive a  short and serve as a dual purpose arc welder if your mains can handle it.  

[TJ Cornish]

1 minute ago, jazzpiano88 said:

That may have been the spec, but DC was getting into the output as you could clearly see in the speaker cone movement.

 

Anyway, there are high end amplifiers that specifically designed to drive very low impudences down to almost DC.
Audio Research had these massive monoblocks designed to meet distortion specs into 1 ohm and 2 Hz!    They are said to drive happily drive a  short and serve as a dual purpose arc welder if your mains can handle it.  

Mea culpa; there are extremely specialized amps without high pass filters.  Not sure that’s the norm in studio or live sound reinforcement situations, but I give.

[jazzpiano88]

Yeah, to some degree I think it’s paying for a spec that will never be challenged, although I’ve heard that these amps have unmatched clarity — maybe because they so effortlessly perform in the normal source material range.  
Each one had 20 6550c tubes with individual bias settings from the front panel and cost roughly $35k/pair.  

[TJ Cornish]

Just now, jazzpiano88 said:

Yeah, to some degree I think it’s paying for a spec that will never be challenged, although I’ve heard that these amps have unmatched clarity — maybe because they so effortlessly perform in the normal source material range.  
Each one had 20 6550c tubes with individual bias settings from the front panel and cost roughly $35k/pair.  

Just clarifying, because I suspect I will get an “I told you so” from someone, clipping does not create DC, even if the amp can produce DC. A sine wave of 50Hz with amplitude increased so that it is now a square wave is still a 50Hz wave; it just has more high harmonics.  Your $35,000 heateramps’s ability to make DC is a different thing altogether.  

[GRollins]

TJ Cornish,

--Lots of hi-fi amps pass DC. Some don't even cost very much money. I happen to own several at varying price points. Get over it.

--A square wave is switched DC by another name. By definition.

--Your attempt to excuse or rationalize someone wanting turning up an unsatisfactory sound system in an attempt to make it sound better is just...peculiar. Maybe it's a "thing" in your area, but I assure you it's not universal.

 

So, with those facts in hand, all of your posts this afternoon implode. Nothing left to debate. There's no substance. Nada. Rien. Smoke on the wind. Move along, nothing to see here.

 

I suspected earlier that it would come to this. Your posts have gone far enough over the line that facts clearly no longer matter. I wish those of good heart well, but this is getting to be a waste of time and I have better things to do. I'm going to bow out of this thread. Everybody have fun, okay?

 

Grey

[TJ Cornish]

6 minutes ago, GRollins said:

TJ Cornish,

--Lots of hi-fi amps pass DC. Some don't even cost very much money. I happen to own several at varying price points. Get over it.

--A square wave is switched DC by another name. By definition.

--Your attempt to excuse or rationalize someone wanting turning up an unsatisfactory sound system in an attempt to make it sound better is just...peculiar. Maybe it's a "thing" in your area, but I assure you it's not universal.

 

So, with those facts in hand, all of your posts this afternoon implode. Nothing left to debate. There's no substance. Nada. Rien. Smoke on the wind. Move along, nothing to see here.

 

I suspected earlier that it would come to this. Your posts have gone far enough over the line that facts clearly no longer matter. I wish those of good heart well, but this is getting to be a waste of time and I have better things to do. I'm going to bow out of this thread. Everybody have fun, okay?

 

Grey

I don’t know why it is desirable for any amp to produce DC; I concede the fact that some may exist in audiophoolery land. They don’t in my world of professional sound systems. A square wave of any audio frequency is not remotely the same as DC. RE our “friend” - a more powerful amplifier of equivalent design doesn’t sound any better than a less powerful amplifier when both are run in their linear range (not clipping). The only reason to seek a larger amp is for more output potential.

 

Thank you very much for ending your continual repetition of your interesting understanding of audio physics. We appreciate it.