Exactly how much headroom?

[[email protected]]

So, exactly how much headroom do you give your speakers? I've heard of people buying amplifiers that can provide twice the recommended RMS rating of the speaker to prevent clipping, and I'm wondering if the folks here follow that same advice. I know you're more likely to damage a speaker by under powering (and I'm using this term loosely) rather than over powering.

Your thoughts?

[Ducatista47]

Depends on what kind of amp and how loudly you play/listen to your system, and to what kind of music.

The technical answer is, according to JBL engineers, ten times continuous (similar or identical to RMS - Root Mean Square) demand to safely cover peaks. At that rate, twice the rated power could be overkill for real world use. A big JBL or Altec at continuous rated power would blow out your hearing. The key is that demand depends on the factors in the first paragraph, and is not what the speaker is capable of handling; it is rather what you are actually going to do with it and is more important than the ratings in determining the power you will actually need to cleanly reproduce music.

For example, a speaker may specify the ability to handle 100 watts RMS. Double that and you get 200 watts. But what if that sensitive classic is so efficient that three watts RMS is really, really loud? (Not unusual for these speakers.) Three watts - the actual demand - times ten is thirty watts. You would need thirty watts to cleanly and safely (for the speakers) play music. Bear in mind that this is a very conservative calculation, using a times ten safety margin, not the times two calculation of the speaker ratings.

If that sounds silly, I have a speaker that is plenty loud at half a watt or less. So five watts is all I need. Welcome to the real world.

Here is my take on the specific power recommendations. I expect most here would disagree.

http://audioheritage.org/vbulletin/showpost.php?p=242888&postcount=24

http://audioheritage.org/vbulletin/showpost.php?p=243132&postcount=30

One thing is for sure, biamping makes getting this right a lot easier. Once you have sorted out biamping, of course. :D

For example, power requirements are so frequency dependent that it would be typical for a subwoofer to need more power than the mains. Biamping yields similar solutions. A big powerful amp to move lots of air for the bass and a finesse amp to render the mids and highs would be an ideal setup.

Clark

[Allanvh5150]

Most speaker manufacturers specify and RMS power and a Program power. Most older drivers are speced with a Program power of double that of the RMS power. Some newer drivers even have a Program power of 4 times the RMS. Some other companies call it Music Power. But basically what they are saying is give your speakers twice what the RMS rated power is.

Allan.

[boputnam]

Here's a little piece from JBL on the topic.

Technical Note - Danger: Low Power (http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3)

[[email protected]]

Here's a little piece from JBL on the topic.

Technical Note - Danger: Low Power (http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3)

Yeah, I have that same file saved to my computer. Just wondering what you do personally.

[Robh3606]

My speakers are in an active set-up. I use a systems aproach not the speaker power ratings. My average SPL is in the mid to upper 80's and I can do 115db peaks before anything clips using just the stereo pair. That is measured where I sit not the 1 meter sensitivity numbers. That gives me a real 20db plus figure.

If I look at the individual drivers I am under powering them. I am using 2123 for midranges as an example. I have 100 watts on each one. The power rating for them is 200 watts. If I gave them 3db of amp headroom that would be 400 watts. Complete overkill in my application.

I would look at it more from that point of view and power accordingly. More power typically won't hurt but there are times it just doesn't make sense. The money could be better spent elsewhere such as a better source componenet.

Rob:)

[Ducatista47]

I would look at it more from that point of view and power accordingly. More power typically won't hurt but there are times it just doesn't make sense. The money could be better spent elsewhere such as a better source componenet.

Rob:)

Or even spent on a better sounding, smaller amp. Which would cost a lot less than a bigger amp of the same quality. That happens to be the vector that steered me to where I am now.

If you ignore the obscenely overpriced "high end" amps and collector pieces, dollars per watt is a rough guide for figuring out amp quality. Sometimes. ;)

Clark

[Mr. Widget]

More power typically won't hurt but there are times it just doesn't make sense. The money could be better spent elsewhere such as a better source componenet.As with all of these sorts of questions it depends on application and expectations... As the JBL paper says, you are more likely to damage a speaker with too little power however putting a 300wpc amp on a tweeter requiring less than 1 watt isn't a good idea from a sonic standpoint. As most people know, amps tend to have rising distortion as the power increases, however not everyone realizes that as the power is reduced the distortion can also rise. In an application where you need 150mW and you are using a large amp, you are not only wasting power, you may be hearing your amp at it's worst. While this is more dramatic in a multi-amped situation, some parallels occur in a mono amp situation.


Widget

[MikeBrewster77]

FWIW, if my amp's meters are accurate I typically listen in the 0.5-3.0W range at a distance of ~ 3.5 meters on speakers with 89db sensitivity (using the "standard" 1 meter measure.) I rarely see a measurement above 5W and I wouldn't exactly say I listen to music at low levels. ;) I have to say having actual meters on my amp has been fairly enlightening, since I would have guess I listened at far greater power levels.

I concur with all of the previous posts that recommend buying the best first watt you can, while still providing yourself sufficient headroom for your particular listening application. Having had monster amps in the past, I was amazed the first time I actually spent some $$$ and bought a HQ amplifier.

Best,
- Mike


Yeah, I have that same file saved to my computer. Just wondering what you do personally.

[boputnam]

...wondering what you do personally.

In the home system, things are way overpowered, because I run things at modest gain, but want the headroom.

In SR, not of relevance here, I match things very carefully to the speaker manufacturer's specs (they put this stuff in their manuals, and if not, I double their "continuous" ratings), and I as-carefully match gain structure between the console, DSP and amps. With the speakers disconnected, I run things to the clip threshold on the console and DSP, and set the amps to match. That way, I know how much headroom I have even when standing at FOH...

(NB - an alternative method used to match Unity Gains, but lacking a real standard and with the increased headroom of today's BIC consoles, you can unknowingly exceed the clip "indicator" threshold margin built-in to the amps.)

[jerry_rig]

I rarely see a measurement above 5W and I wouldn't exactly say I listen to music at low levels. ;) I have to say having actual meters on my amp has been fairly enlightening, since I would have guess I listened at far greater power levels.

Strangely, I found just the opposite when I recently installed a pair of 2235H bass drivers in my system, connected directly to a 300 WPC Class A Krell amplifier. The Krell has lights to indicate current draw and I can reach the second level (out of four) without much strain. That said, my level settings for the amp driving the top section (2122, 2441 and 2405) are much lower -- for equivalent volume -- than they were when driving a pair of small bookshelf speakers. So I guess this is simply a way to say that power is VERY frequency dependent. Not a shock.

[Hoerninger]

... I match things very carefully to the speaker manufacturer's specs,
... and I as-carefully match gain structure between the console, DSP and amps. ,
...and set the amps to match.

Yes, and this holds for home entertainment too IMHO, not only for SR. But in home environments there can be severe limits in environmental noise floor and max volume. So you are limited to a dynamic range of only e.g. 30dB - this gives the illusion of more freedom in the setup.

Did we already mention cone excursion limit and thermal limit?
___________
Peter

[Allanvh5150]

Strangely, I found just the opposite when I recently installed a pair of 2235H bass drivers in my system, connected directly to a 300 WPC Class A Krell amplifier. The Krell has lights to indicate current draw and I can reach the second level (out of four) without much strain. That said, my level settings for the amp driving the top section (2122, 2441 and 2405) are much lower -- for equivalent volume -- than they were when driving a pair of small bookshelf speakers. So I guess this is simply a way to say that power is VERY frequency dependent. Not a shock.

I can verify that as well. I have two pairs of 2235's in my music room. They are driven by a Perreaux PMF 5150 which is good for about 1000wats RMS into 4 ohms. Listening at moderate levels the meters run around 3-6db below clip. The same setup has a pair of L150's driven by 300 watts RMS and that runs about the same amount below clip. IMO large amplifiers are the way to go. Max Headroom!

Allan.

[MikeBrewster77]

Class A's typically run in a higher current draw range than a "standard" amp, no?

Good point about the frequency range vs. power - I did fail to mention that in my set up what goes to the amp is high-passed at 100hz, and everything below feeds to the sub's internal amp :o:


Strangely, I found just the opposite when I recently installed a pair of 2235H bass drivers in my system, connected directly to a 300 WPC Class A Krell amplifier. The Krell has lights to indicate current draw and I can reach the second level (out of four) without much strain. That said, my level settings for the amp driving the top section (2122, 2441 and 2405) are much lower -- for equivalent volume -- than they were when driving a pair of small bookshelf speakers. So I guess this is simply a way to say that power is VERY frequency dependent. Not a shock.

[Rolf]

One can "never" get too much power, but as stated by others a high power amp is more expensive than a low power amp with the same sound quality, but that is up to each how much money one want to spend on the system.

My setup maybe as some says an "overkill", but I newer have to worry about distortion. BUT, one must be careful with the volume control.

Here is a picture of my setup:

[JBL 4645]

In the home system, things are way overpowered, because I run things at modest gain, but want the headroom.

In SR, not of relevance here, I match things very carefully to the speaker manufacturer's specs (they put this stuff in their manuals, and if not, I double their "continuous" ratings), and I as-carefully match gain structure between the console, DSP and amps. With the speakers disconnected, I run things to the clip threshold on the console and DSP, and set the amps to match. That way, I know how much headroom I have even when standing at FOH...

(NB - an alternative method used to match Unity Gains, but lacking a real standard and with the increased headroom of today's BIC consoles, you can unknowingly exceed the clip "indicator" threshold margin built-in to the amps.)
bop

So what your saying is, that levels on barograph display mixing counsel or audio loudspeaker monitor crossover system are near at clip level and are matched in similar way with barograph display on the power amplifier?

[Ducatista47]

Strangely, I found just the opposite when I recently installed a pair of 2235H bass drivers in my system, connected directly to a 300 WPC Class A Krell amplifier. The Krell has lights to indicate current draw and I can reach the second level (out of four) without much strain. That said, my level settings for the amp driving the top section (2122, 2441 and 2405) are much lower -- for equivalent volume -- than they were when driving a pair of small bookshelf speakers. So I guess this is simply a way to say that power is VERY frequency dependent. Not a shock.


I can verify that as well. I have two pairs of 2235's in my music room. They are driven by a Perreaux PMF 5150 which is good for about 1000wats RMS into 4 ohms. Listening at moderate levels the meters run around 3-6db below clip. The same setup has a pair of L150's driven by 300 watts RMS and that runs about the same amount below clip. IMO large amplifiers are the way to go. Max Headroom!

Allan.

Help me out on these numbers. If the Krell lights indeed represent current draw instead of output, that might make sense. A class A tube amp typically draws 50% of max current at idle. That is, output at zero. Also, perhaps the four lights are logarithmic rather than arithmetic.

A MOSFET class A also uses massive current to yield a small output. The First Watt F2 draws 200 watts and is rated at five watts output. Still, 3-6dB below clip seems mighty strange for that setup. Four 2235's indoors - not SR - should be quite loud, not at moderate volume, with something like 500 watts going through them. Do the SPL versus watts calculations for your listening distance and see if it makes sense for 125 watts per driver. I am a little suspicious of the accuracy of the clip indicators. Even if the indicators were peak displays rather than continuous power, that would still be at least 12-20 watts RMS or more per driver, very loud unless they are in dreadfully inefficient enclosures.

Tube Krells and MOSFET designs put out a lot of heat. That is where most of the current goes, not to the voice coils.

Clark

[Rolf]

Help me out on these numbers.
Clark

I am not sure what you are talking about. My teknikal English's is not an A in these questions.

Do you mean that xtra power in needed? If so I agree. If not, please read the manual.

[boputnam]

I am not sure what you are talking about.+1


Help me out on these numbers. er, +1


Listening at moderate levels the meters run around 3-6db below clip.

Clearly, there are different standards in-play here, and different things being displayed than what one might think.

FWIW, Allan, when I run at "3-6dB below clip", it is hella loud, and it is all I will give it (see example meter LED, imbed). I simply WILL not drive above that point. (FWIWx2, if the fans want it louder and the system too small, I simply tell them to "move up". :) ). I wonder if you are talking about 3-6dB below "0"...?

As I say, clearly there must be different things being displayed than what is thought, or to have only "moderate levels", there is some serious attenuation in the speaker leads.

[Robh3606]

One can "never" get too much power,


My setup maybe as some says an "overkill",


Hello Rolf

It's all relative. I was speaking about my system which is active. If my midrange was in a passive set-up with a 2235 you would have about 5-6 db of passive attenuation. So if I was using a 400 watt amp on that set-up I would only have 100 watts available to drive the 2123 because of the of the attenuation in the passive network.

That's the same power I am using in an active set-up. So it's a wash.

The woofer sensitivity/power handling are always the determining factor for system power requirements. Because of this power requirements are always application and system dependent.

How you power your system using either a systems approach or speaker power handling as a guide is up to you.

Rob:)

[Ducatista47]

Clearly, there are different standards in-play here, and different things being displayed than what one might think.

As I say, clearly there must be different things being displayed than what is thought, or to have only "moderate levels", there is some serious attenuation in the speaker leads.

Thank you, Bo, for the hundredth time I think. :) Like I tell friends, if you have a an injury, or chronic muscle or connective tissue pain, forget your regular medical personnel and see a sports medicine pro. Likewise, if you want to know about SPL, power and headroom issues, ask an SR pro. It is not my place, but when I read things like this thread I want to say, "Ask Bo or Subwoof."

All I have to work with are some minor EE chops - very minor - and the possession of comparative logic. And perhaps experience listening to a bazillion systems starting in the 1950's.

I was trying to say that it seemed apples were being talked about but oranges were being read off the displays. Simply running the numbers showed that if these amps deliver as advertised, they would have a ton of headroom with efficient speakers; 3-6 dB below clip would bend those little hairs in the inner ear double.

So my conclusion was either apples and oranges or huge losses somewhere else. Losses not being the case, I would trot out my old saw that if you want to buy 400% too much amp for your needs, it is your money.

Clark

[Robh3606]

400% too much amp for your needs, it is your money.

Sounds like a lot but it's not only a 6db increase in headroom. That would be the minumum for a noticeable change. Once you start getting power levels over 100 watts or so things get out of hand fast.

Rob:)

[Allanvh5150]

+1

er, +1



Clearly, there are different standards in-play here, and different things being displayed than what one might think.

FWIW, Allan, when I run at "3-6dB below clip", it is hella loud, and it is all I will give it (see example meter LED, imbed). I simply WILL not drive above that point. (FWIWx2, if the fans want it louder and the system too small, I simply tell them to "move up". :) ). I wonder if you are talking about 3-6dB below "0"...?

As I say, clearly there must be different things being displayed than what is thought, or to have only "moderate levels", there is some serious attenuation in the speaker leads.

3-6db below clip can only mean one thing. The meters on my amps indicate actual power levels and they even take the supply voltage into acount. My idea of a moderate level may of course be somewhat louder than most people. Also one must remember that the meters are reading insatantaneous power. Music is not constant and although the peaks may hover aroud 600 - 800 watts, the average power may only be 200 watts.

Allan.

[boputnam]

3-6db below clip can only mean one thing. The meters on my amps indicate actual power levels and they even take the supply voltage into acount. I think that's it.


My idea of a moderate level may of course be somewhat louder than most people. I don't think so - hell, you and I both know what -3 to -6B below clip soundsd like at FOH! :p

[Rolf]

Hello Rolf

It's all relative. Rob:)

Yes, I know. I use electronic crossover. At my picture you can see it. (Top right) I use two identical power amps. Left amp, left ch goes to woofer, right ch to the rest. Same for the right ch. Works perfectly, and is much better than using one amp for woofer and one for the rest. I have tested this.

I am now waiting for new charge coupled crossovers. They should be arriving soon.

After a about 14 days the new crossovers will perform good. I will post my experience about this later.

[Allanvh5150]

I think that's it.

I don't think so - hell, you and I both know what -3 to -6B below clip soundsd like at FOH! :p

Depends how big your system is!:D

[Ian Mackenzie]

So, exactly how much headroom do you give your speakers? I've heard of people buying amplifiers that can provide twice the recommended RMS rating of the speaker to prevent clipping, and I'm wondering if the folks here follow that same advice. I know you're more likely to damage a speaker by under powering (and I'm using this term loosely) rather than over powering.

Your thoughts?

If you are using them for a studio the recommendations in John Eargle's book suggest 6 db (power) headroom above the average mean SPL level you would be using at the desk. A good way of doing this is to biamp rather then use an amp that is 6 db more powerful.

Its all relative the efficiency of the loudspeaker and the listening distance from the system and of course the average SPL you want. The efficiency of the loudspeaker is a far more important factor in the equation because for each 3 db increase in sensitivity (the measure for SPL output over a given frequency band for a given power input) the power required for the same SPL is half.

So if your speakers were 96 db and you were using a 200 watt amp for the 6 db headroom that would be fine. But if the sensitivity was lowered to 93 db you would need a 400 watt amp and for another 3 db lower to 90 db you would need an 800 watt amp.

As I recall the SPL drops about 6 db for each doubling of the distance (depends in the acoustics). Loudspeaker sensitivity is usually quote at 1 watt /1 meter. 10 db is regarded as twice as loud.

Once you run some numbers you can see why it all gets too hard if the sensitivity is below 93 db / 1 watt /1 meter.

In respect to meters what they are actually indicating can vary widely.

Some are set up for average or peak values but only a Led clipping indicator would be fast enough to indicate the true peak power into the load.

Typically on an uncompressed signal (music) the peaks can be 6-10 db higher than the average level.(see above)

The point is that you need to avoid any possibility of overloading the amp(s). But it is very easy to run out of power and this is why you need to work out how much reserve power you need.

Given a 200 watt/channel amp is lower in cost and more readily available then a 400 watt amp it becomes a bit more rational as to what maximum average SPL you can have with 6 db headroom.

So in plain language you really only want to be cruising at 50 watts a side on average mean listening levels for the SPL you want at the listening position. You can then work out if your loudspeaker has sufficient sensitivity.

I practise this approach works very well and you will find the system runs cleaner and with more apparent dynamic range than it would if you simply worked on the basis of forcing the system to max out at your desired listening SPL.

After that you either get more sensitive speakers or biamp with 200 watts on the mid/high and typically 300-400 watts on the lows (a side) which on paper gives about 6 db more headroom if crossing over at 300 hertz.

Some people also bridge both channels of the amp to make it a mono high power channel . Refer to the manual before considering this and check the maxium rms and peak rating of the loudspeaker.

A hidden problem that raises its ugly head is that loudspeakers suffer power compression at anything above -10 db of the maxium rms power input and as you approach their full ratings you can loose in the order of 3-4 db of the full ouput because of voice coil heating. Most loudspeakers fail before you get to that point.

JBL have built in design features to minimise power compression like 4 inch voice coils but as you can appreciate going up twice in power is not the smart way of making it go louder.

Its no surprise loudspeakers (monitors) with 96 db sensitivity sound more realistic than a monitor with 90 db sensitivity.

[Allanvh5150]

The main reason that I have very large power amplifiers is so that under normal conditions the amps are just at tickover. All the reserve in the world and absolutely no chance of clipping. Distortion on the perreaux's is in the order of 0.001% at full power and can drop to 0.0005% at lower levels when the amp is essentually running class A. Power is very cheap especially if you build it yourself. I have never blown a driver from too much power. On the otherhand, a squeal from a mic can easily push an amplifier well into clip and for quite a long time. I have seen many drivers toasted in this manner. I will stick with my rule of thumb of twice the RMS power of the driver.

Allan.

[Robh3606]

I will stick with my rule of thumb of twice the RMS power of the driver.

Hello Allan

Even with a compression driver?? Passive I can see that depending on the attenuation, but in an active set-up?? Or a biamped set-up??

Rob:)

[Allanvh5150]

Yup. The last SR rig that I ran had a 2404 + 2405 on the top end each side. Each driver had 300 watts available to it. That's right: 2 300 watt per channel amplifiers. In SR I always used the same amps throughout the whole system except for the bottom end. Those amps were different. It made it easy to put a system together quickly. One amplifier channel per driver. Bottom end usually had 500 watts per driver, low mids 300 watts per driver, Hi mids 300 watts per driver but with 16 ohm drivers this will drop to 150 watts, hi's also had 300 watts per driver.

I run L150's at home and if I powered them with anything less than 300 watts they would sound pretty blousey. They are speced ta 89db I think.

Allan.

[boputnam]

Even with a compression driver?? ...in an active set-up?? Or a biamped set-up?? :flamed:

[Ducatista47]

Yup. The last SR rig that I ran had a 2404 + 2405 on the top end each side. Each driver had 300 watts available to it. That's right: 2 300 watt per channel amplifiers. In SR I always used the same amps throughout the whole system except for the bottom end. Those amps were different. It made it easy to put a system together quickly. One amplifier channel per driver. Bottom end usually had 500 watts per driver, low mids 300 watts per driver, Hi mids 300 watts per driver but with 16 ohm drivers this will drop to 150 watts, hi's also had 300 watts per driver.

I run L150's at home and if I powered them with anything less than 300 watts they would sound pretty blousey. They are speced ta 89db I think.

Allan.

Allan, I can understand that quickly being able to get a system up and running for a gig is a great thing. But I don't see how that serves a system for listening in a room at home. I'm no Pro, but there seem to be some big differences between what works for SR and what works in a moderate sized room with an audience of one.

Concerning the power requirements of a 2405, I defer to Greg Timbers.

From http://audioheritage.org/vbulletin/showpost.php?p=110075&postcount=27

The ring radiator hates passive networks. A major improvement in the upper range would be to drive the 2405 from its own little amp. You only need 3 or 4 v rms. The 2405 does 110 dB for 2.83v. It is padded way down in the system. There is little real power at those frequencies anyway. You only need to know the voltage output of the amp, power is irrelevant. The 2405 is about 12 ohms and won't draw much current. I would use some little chip amp with a 2nd or 3rd order low level highpass in front of it. Take off the passive network to the ring and just feed it straight. Make sure the amp doesn't make a DC thump on turn on or turn off. That will fatigue the diaphragm. The amp will also have to have really low noise characteristics as any hiss will be really loud directly into the ring. I used to use an old Marantz 1030 integrated amp to run my rings. I could separate out the power amp section and the tweeters always sounded really good.

As for running big amps at tickover, I'm with Widget on this one. Tube amps maybe, if they are dead quiet, but most SS amps sound like hell at very low power (as compared to the sweet spot). It is the nature of the beast.
Clark

[Ducatista47]

My bottom line on these issues is that killing a fly with a sledgehammer is a bad idea, is good only as an example of using the wrong tool for the job, and in the real audio world suffers in comparison to better approaches and in ways we can hear. Fifty years of listening to systems has not turned up an exception yet when apples are compared to apples.

You can be too rich and too thin, and it is possible to have too much power. (I love hitting more than one target with one shot.) I notice that more forum space than we think is taken up by issues related to and caused by the use of high powered, complicated systems. To each his or her own, but try this: music player + small integrated tube amp + high efficiency speaker + ears = GREAT sound, few connections, no outboard gear, few dollars. Toss in a subwoofer and high power doesn't have a leg to stand on.

(My speakers have 97 and 98 dB efficiency, minimum.)

If this post is offensive, read Ian's post and you won't have to read mine. As usual!

Clark

[Mr. Widget]

You can be too rich and too thin, and it is possible to have too much power...I do agree with your less is more premise, but I disagree with only one route toward that end. The Bryston B-100 SST is an excellent integrated that also has a space for an optional excellent DAC and a phono section. With the Bryston's 100wpc you can open up your possibilities to a wider range of loudspeakers and while the magical midrange of some tube amps is lacking, the accuracy and control will more than make up for it for many listeners. A higher cost but also excellent integrated is the Pass Labs INT 150... it almost sounds like fine tubes without the down side.


Widget

[Ducatista47]

Sorry, Widget, the example was just that, and my choice of tube amps was personal. While I see no alternative to high efficiency speakers for the ultimate sound, I have no problem with well done power however it is arrived at.

But even Nelson Pass could not design a powerful amp nearly as great sounding as his five and ten watt designs. And he surely has tried. The 25-30 watt Aleph J is as close as he as come. There are several other reasons as well why high efficiency is highly desirable for speakers (they have more to do with how a speaker works than how much power they need), but that is a big one.

In any case you are being very kind, Widget. At this point, I could understand someone saying "Clark, shut the hell up." ;)

Clark

[Mr. Widget]

There are several other reasons as well why high efficiency is highly desirable for speakers (they have more to do with how a speaker works than how much power they need), but that is a big one.I hear you, but I haven't heard many high efficiency designs that are universally superior to more moderately sensitive designs.... I appreciate what the HE speakers can do, but these designs almost universally lack accuracy to achieve maximum sensitivity. I do understand that tonal accuracy is not the paramount quality qualifier for many, and we are all capable of making internal "equalization" to compensate, but for this listener, tonal accuracy is very important.


Widget

[Ducatista47]

Widget, I think I am about in the middle. This commentary at Stereo Times is a nice talking point.

http://www.stereotimes.com/comm011602.shtml

My favorite speakers are still the Hammer Dynamics Super 12's, certainly not everyone's cup of steaming Dragonwell but far and away better and more versatile to my ears than any other single driver augmented I have heard.

I would go to the 4345's for really loud stuff. Same efficiency but otherwise a different universe. Their tonal accuracy is tough to criticize!

Clark

[Mr. Widget]

No, but if we are to continue... a new thread is in order. :)


Widget

[Chas]

As most people know, amps tend to have rising distortion as the power increases, however not everyone realizes that as the power is reduced the distortion can also rise. In an application where you need 150mW and you are using a large amp, you are not only wasting power, you may be hearing your amp at it's worst. While this is more dramatic in a multi-amped situation, some parallels occur in a mono amp situation.
Widget

A very good justification for the new Bryston SST/2 (squared) series. Lower distortion at the bottom end of the demand for power. Guess what I'm listening to for the last few weeks on the 4345's, top and bottom?;) Surprising performance given that they are a solid state design. Maybe it's time to pitch those tube amps after 35+ years....:D

[Hoerninger]

;) Surprising performance given that they are a solid state design. Maybe it's time to pitch those tube amps after 35+ years....:D
Congrats for your amp. :applaud:
Surprising - no. Important are the first 5 watts, which can be improved by an appropriate quiescent current. Old rule.
But where are these nice second order harmonics? :(
____________
Peter

[Allanvh5150]

Well I have listened to 4 different Perreaux models. PMF 1150 (100wpc), 2150 (200wpc), 3150 (300wpc) and the 5150 (500wpc) all into 8 ohms. To be perfectly honest I cant tell the difference between any of them and low power, medium or high. The 5150 has a ton more grunt but as far as the sound goes, they are identical. One thing though, I am nowhere near clip with the big ones and thats how I like it. I am currently working on a monster multi channel amplifier. All channels are the same output (500 watts into 8 ohms) but all are no created equal. The channels for bottom end have 5 pair of mosfets, the midrange channels have 3 pair of mosfets and the channels for top end have only 1 pair. Obviously if you plug a subwoofer into a hi channel you will cook the amplifier. I have built crossovers into the circuit so this can never happen. This type of system has been done before and it works extreamly well.

One can never have too many sneakers, too many T-shirts or too much power.

Allan.

[boputnam]

I would go to the 4345's for really loud stuff. Same efficiency but otherwise a different universe. Their tonal accuracy is tough to criticize!Agree - but I reallly have come to admire their ability at very low volume. It never ceases to amaze me, particularly the 2245H. As Giskard once said, "give it a watt, it gives it all back..." (or something to that end).


A very good justification for the new Bryston SST/2 (squared) series. Lower distortion at the bottom end of the demand for power. Guess what I'm listening to for the last few weeks on the 4345's, top and bottom?;) Surprising performance given that they are a solid state design. Maybe it's time to pitch those tube amps after 35+ years....:DThat is ringing in my ears. Next cash cache I think is going into a pair of Brystons for me, too. :)


Congrats for your amp. :applaud:
Surprising - no. Important are the first 5 watts, which can be improved by an appropriate quiescent current. Old rule.
But where are these nice second order harmonics? :(
I just really like this post.

[Chas]

Congrats for your amp. :applaud:
Surprising - no. Important are the first 5 watts, which can be improved by an appropriate quiescent current. Old rule.
But where are these nice second order harmonics? :(
____________
Peter

I know, but these new Brystons actually run cooler at idle than previous models. Second harmonics? Yeah, well - I guess I am not ready to ditch all the tube amps, quite yet...:o:

[Chas]

That is ringing in my ears. Next cash cache I think is going into a pair of Brystons for me, too. :)

Yup, the 4B SST/2 is attached to the 2245H's and a 2B SST/2 is loafing above 290Hz. Both are massive overkill.

I will continue to use my tube amps for high pass service occasionally. They can still do some very nice stuff that SS can't touch. Are they accurate? Who cares? :D

[Hoerninger]

I am currently working on a monster multi channel amplifier. All channels are the same output (500 watts into 8 ohms) but all are no created equal. The channels for bottom end have 5 pair of mosfets, the midrange channels have 3 pair of mosfets and the channels for top end have only 1 pair.

Are you willing to share more details? (link, literature)
____________
Peter

[TonyM]

So, exactly how much headroom do you give your speakers? I've heard of people buying amplifiers that can provide twice the recommended RMS rating of the speaker to prevent clipping, and I'm wondering if the folks here follow that same advice. I know you're more likely to damage a speaker by under powering (and I'm using this term loosely) rather than over powering.

Your thoughts?

So getting back to the original question, I have no idea what my speakers are rated for power wise and I've always used the best sounding biggest amp I could afford. I haven't blown a single driver since they stopped making Advent speakers.

Most speaker systems (not individual drivers) tend to be rated for more than 200 watts short term now days, of course there are always exceptions. I think the big question that I've seen already presented is how efficient is the speaker and how big is the room. 25 watt amps have their place driving super high efficiency speakers in a moderate size room. I'm guessing if there is a single ended tube amp in your future you're not expecting 100dB SPLs in your 1000 sq ft room with your small sealed exotic french speakers, nothing against the French.

If you're much below 90dB/W/m in a good size listening room than it's got to be 150 to 350 watts or more per channel per side. Most of the time you'll cruise along well under 10 watts per side, even for moderate peaks, but if it's not there when you need it you'll know. Most good quality modern amps sound fine loafing along at low power levels. In fact most good size amps will actually stay in class A at SET size levels.

I will be the first to admit that 10 watts in the wrong hands can smoke a tweeter voice coil or rattle an unloaded woofer but that just starts to come under abuse. I think in JBL's older literature they basically gave you a power rating but also told you as long as the amp doesn't clip, the speaker doesn't exceed its excursion limits and you don't drive it till it sounds like its going to blow bring on the big guns. The system should cry for help long before you smoke something and if you couldn't tell it was probably too loud anyway.

I don't mean to be overly critical, I'm sure some people have legitamately blown speakers but I doubt if many of them blamed it on haveing too big an amp just not enough speaker.

Sound reinforcement is a whole nuther' animal. Then again there's a ton of information on how to work that stuff out.

[Rolf]

You should try their (Perreaux) newer stuff. Sounds much better. I had the PMF2150-B, and the newer stuff is much better.



Well I have listened to 4 different Perreaux models. PMF 1150 (100wpc), 2150 (200wpc), 3150 (300wpc) and the 5150 (500wpc) all into 8 ohms. To be perfectly honest I cant tell the difference between any of them and low power, medium or high. The 5150 has a ton more grunt but as far as the sound goes, they are identical. One thing though, I am nowhere near clip with the big ones and thats how I like it. I am currently working on a monster multi channel amplifier. All channels are the same output (500 watts into 8 ohms) but all are no created equal. The channels for bottom end have 5 pair of mosfets, the midrange channels have 3 pair of mosfets and the channels for top end have only 1 pair. Obviously if you plug a subwoofer into a hi channel you will cook the amplifier. I have built crossovers into the circuit so this can never happen. This type of system has been done before and it works extreamly well.

One can never have too many sneakers, too many T-shirts or too much power.

Allan.

[Allanvh5150]

You should try their (Perreaux) newer stuff. Sounds much better. I had the PMF2150-B, and the newer stuff is much better.

I would agree. But the old stuff looks better and I like vintage sledgehammers!

Allan.:D

[Rolf]

I would agree. But the old stuff looks better and I like vintage sledgehammers!

Allan.:D

Old stuff looks better? OK, that is a personal opinion. As I understand we are different in the opinion about sound in general. I go for the best (that is what I can afford to spend) possible sound, including upgrading crossovers in my 4343's, and you want it as original as possible. Am I right?