Why you need 500Wpc for good sound

[Islander]

Here's an interesting opinion from Anthony Michaelson of Musical Fidelity, a well-respected audio company. Keep in mind that he considers most high quality speakers to have a sensitivity of around 87dB.

http://www.musicalfidelity.com/news/letter.html

[SWL]

Well, I've been running 500 watts to the highs........500 watts to the lows on my RF-7's using an active crossover. Keeping the gains on the amps at 75% and the gains on the active crossover at 25% I've been experiencing output, headroom and clarity like never before with 200 watt amps. I would say that the extra power......in comparison to lesser powered amps prior.......controls the speakers much better. Tighter bass, better separation, smoother midrange etc.

I even had an 8 watt tube amp paired up with a JM Peach preamp that left the 7's sounding lifeless. Sold the 8 watt tube amp to a friend.......he runs it with Cornwalls.......and they sound awesome.

I'm not against running lesser power. This so far is what I've found to make the 7's sound their best.

[jbsl]

SWL how big is your room and how many watts do you actually use?

[SWL]

jbsl,

My main two-channel system covers the whole first floor which is approx. 900 sq. ft. Two listening rooms that are adjacent to each other.......including a kitchen, dining room and foyer.

How many watts are actually used? It's my understanding that maybe between 10 and 30 watts are used continuously........and that the rest of the wattage only plays a roll in certain parts of the music. Based on the research I've done on the RF-7 I went with the bigger power supply. Compared to the 100 wpc receivers......200 wpc amps I've used prior.......500 to the highs and 500 to the lows is absolutey what the 7's needed to make them shine (to my ears).

Covering this much area........three pairs of RF-7's powered this way......along with some quality subbage works pretty well. []

[LarryC]

SWL -- OT -- did you ever find something interesting to attend live-musicwise in your area?

[Guest " "]

In a 14X18 room....rarely go over .25 watts. At .25 watts, I can hear the music outside for 25ft any direction.

The amp in question can produce 200 watts per channel class A continuous into 4 ohms, and crazy numbers like 500 wpccontinuous at 1 ohm.

The room in question has 10" cement walls on two sides, and 6" framed walls on the other two (drywall, plywood, 3.5" foam sheets, cement board), and has a 4 inch insulated rasied floor over a 6" poured slab.

You have to factor Speaker SPL when comparing how many watts you need. There are many SPL calculators on the web.

[seti]

104DB 1w 1m or why you don't need 500wpc for good sound.

What the world needs is a good 5 watt amplifier. PWK

[SWL]

SWL -- OT -- did you ever find something interesting to attend live-musicwise in your area?

In a couple of months when work slows down, I'll probably attend the MSO or something in Chicago. Too busy right now....but I'm really looking forward to the experience. []

[ClaudeJ1]

What a bunch of crap. Those are space heaters and so are the voice coils that have to dissipate that heat. I would like to see ALL amplifiers rated in DB Watts. So a One Watt amplifier= 0 dbW, 10 Watts= 10 dbW, 100= 20 dbW, 1,000W= 30 dbW. So everything would fall in with those numbers. Add 3 db for 4 ohm loads in SS amps, leave alone for tubes with output Xformers.

I prefer to run big horns (cubic feet), which I have, after padding down the most efficient component have 108 db of efficiency. So if I take his numbers, I need 21 dbW less power to do the same job. A 500 Watt amp. is 27 dbW, so subtracting my 21 from his 27, I get a 6 dbW result. So I can basically do the same job with 4 watts and my MWM stack that he can do with his space heaters that happen to make noise with 500 W.

Also using a big amp on efficient speakers is bad. You will never use it unless you want to go to PERMANENTLY damage your hearing AND since S/N ratio is based on full output vs. noise, the lower power ones are less noisy in the MILLIWATT level, which is all you need to listen to 100+ db/W Klipsch speakers.

PWK was always frustrated by the amplifier power race, which led him to call amp greater than about 50W/ch a "stove." It's also the reason why LaScalas were sold with K-43's to the discos of the late 70's. They used to melt solder joints with those big stoves.

Jim Hunter once pegged an OSHA guy's sound meter with a 200 Watt Ampzilla on an MCM-1900 (like mine) 100 feet away OUTDOORS.

Some of these writers need to get a clue.

[DrWho]

Here's an interesting opinion from Anthony Michaelson of Musical Fidelity, a well-respected audio company. Keep in mind that he considers most high quality speakers to have a sensitivity of around 87dB.

http://www.musicalfidelity.com/news/letter.html

So with a 100dB speaker, you would need 13dB less watts, which would correlate to about 25W using his calculations. Throw in 6dB of headroom to ensure you're still in linear operation and you're looking at about 100W...

Transient peaks in music are just killer, but then I have to wonder if people just generally like the sound of soft limiting.

[ClaudeJ1]

So with a 100dB speaker, you would need 13dB less watts, which would correlate to about 25W using his calculations. Throw in 6dB of headroom to ensure you're still in linear operation and you're looking at about 100W...

Transient peaks in music are just killer, but then I have to wonder if people just generally like the sound of soft limiting.

Transient peaks are killer, but with a sanme 78-88 db average listning level with a 108 db speaker (x2 ch, so 111 combined), and a 10 db drop at the listening position, I'm down in the 0.1 watt range most of the time. LaScala and Khorn owners user about 0.25 watts or 2.5 times that. PWK was a symphony man and he told me 17 db was all you needed for headroom, so if you round up to 20 db, is't 100X nominal. So if I multiply my 0.1 watts X100, 10 Watts is all I need, and that's mostly on the woofer section. Dividing the 4 horn woofers I use, I get 2.5 watts per bin for the PEAKS. Even for movies, where the horns are used for sub-bass, I never use more thatn 10 W on peaks.

So, yes the Khorn and LaScala people would need 5-20 W/ch to do the same job. This is why if you want robust levels at LOW distortion with max dynamics, you need an all horn system with lower power, not some over priced EuroTrash direct radiator speaker with a Kilowatt of power, puhlease.

Figure this one out when I was 14 years old by just hanging out at a Klipsch dealer.

[oldtimer]

So why haven't the brits and europeans figured it out? The horn guys over there are true mavericks, and far and few between.

[Guest " "]

" Transient peaks are killer, but with a sanme 78-88 db average listning
level with a 108 db speaker (x2 ch, so 111 combined), and a 10 db drop
at the listening position, I'm down in the 0.1 watt range most of the
time. LaScala and Khorn owners user about 0.25 watts or 2.5 times that.
PWK was a symphony man and he told me 17 db was all you needed for
headroom, so if you round up to 20 db, is't 100X nominal. So if I
multiply my 0.1 watts X100, 10 Watts is all I need, and that's mostly
on the woofer section. Dividing the 4 horn woofers I use, I get 2.5
watts per bin for the PEAKS. Even for movies, where the horns are used
for sub-bass, I never use more thatn 10 W on peaks."

I agree, I think that's a better way of looking at this .

If I'm using 1/4 watts most of the time..... then 2.5 watts would give me head room X, 25 watts would give me head room X times 2.

At head room X.... 2.5 watts..the cops would be at my door.

[artto]

Here's an interesting opinion from Anthony Michaelson of Musical Fidelity, a well-respected audio company. Keep in mind that he considers most high quality speakers to have a sensitivity of around 87dB.

First of all Antony Michaelson DID NOT say “that he considers most high quality speakers to have a sensitivity of around 87dB”.

What he said was “I strongly believe that with an ordinary high quality loudspeaker of about 87dB sensitivity you’ll need bout 500 watts to avoid any clipping or limitation”.

Keyword: ordinary

I can only speak for myself, but I didn’t buy Klipschorns because they were “ordinary” anything.

Second Keyword: believe

He “believes” ? Yeah right. That tells me he doesn’t actually KNOW.

The problem with his “beliefs” is that by the time a speaker of this low sensitivity approaches life-like sound levels in any reasonably good sized room with proper acoustical treatments, the speaker literally can either no longer absorb the amount of power required to produce the louder sound levels without destructing, and/or cannot do so with low distortion. And this is not to mention the “compression” that normally occurs as the speaker plays louder and louder.

He obviously does not recognize “the FACT that distortion is approximately inversely proportional to efficiency and that uniform efficiency relates to flatness or uniformity of output with respect to frequency or so-called flat response”. (PWK’s words not mine).

If you’re using something reasonably efficient, say around 100dB/w/m or so, and inserting a high powered amplifier makes a positive difference to you, then I aver that something else other than the available power is the cause of the so-called “improvement” in sound quality.

And I have to wonder what does Michaelson mean by “ordinary high quality”? Isn’t that an oxymoron?

[fenderbender]

Same reason a car with 600 hp is better than one with 200 hp.... bragging rights!!!!

[oldtimer]

You might not believe it fella, but it will cure your asthma too.

[Jay481985]

Here's an interesting opinion from Anthony Michaelson of Musical Fidelity, a well-respected audio company. Keep in mind that he considers most high quality speakers to have a sensitivity of around 87dB.

http://www.musicalfidelity.com/news/letter.html

So with a 100dB speaker, you would need 13dB less watts, which would correlate to about 25W using his calculations. Throw in 6dB of headroom to ensure you're still in linear operation and you're looking at about 100W...

Transient peaks in music are just killer, but then I have to wonder if people just generally like the sound of soft limiting.

25 watts or 100 watts translated in my room will be above 130 db. I probably use a good watt if I am critically listening. Most of the time I doubt its a watt.

[SWL]

.....ya learn sumthin new every day. [:$]

[DrWho]

25 watts or 100 watts translated in my room
will be above 130 db. I probably use a good watt if I am critically
listening. Most of the time I doubt its a watt.

Ever measured it? It's called crest factor...

2. Suppose you have an amplifier rated at 120 watts continuous.
How much clean continuous power can it deliver to a loudspeaker
when fed with a 20 dB crest factor signal?

Converting the amplifier rating into a level, we have 20.8 dBW.
We can add 3 dB since the amplifier was rated using a sine wave
(+23.8 dBW). Subtracting the crest factor of the signal (23.8 -
20) leaves 3.8 dBW. Converting back to watts we have 2.4 watts.

http://www.prosoundweb.com/install/synaudcon/news27_1/epr_p2.php

That 2.4W on a 100dB speaker is gonna measure about 100dB at 1meter
with an SPL meter (thanks to the integration time of the needle). Some of my favorite recordings have crest factors
closer to 30dB...making that a mere 0.24 effective watts from a 120W
amplifier (yikes)...that'll be measuring under 94dB on an SPL meter,
even though it's almost clipping the amp. And we're talking at 1m...it only gets worse the further back from the speakers you sit.

Or how bout we do the math on a 1W amplifier with 20dB crest factor...a 100dB speaker will be doing at most 83dB at 1m.

[tigerwoodKhorns]

Here's an interesting opinion from Anthony Michaelson of Musical Fidelity, a well-respected audio company. Keep in mind that he considers most high quality speakers to have a sensitivity of around 87dB.

First of all Antony Michaelson DID NOT say “that he considers most high quality speakers to have a sensitivity of around 87dB”.

What he said was “I strongly believe that with an ordinary high quality loudspeaker of about 87dB sensitivity you’ll need bout 500 watts to avoid any clipping or limitation”.

Keyword: ordinary

I can only speak for myself, but I didn’t buy Klipschorns because they were “ordinary” anything.

Second Keyword: believe

He “believes” ? Yeah right. That tells me he doesn’t actually KNOW.

The problem with his “beliefs” is that by the time a speaker of this low sensitivity approaches life-like sound levels in any reasonably good sized room with proper acoustical treatments, the speaker literally can either no longer absorb the amount of power required to produce the louder sound levels without destructing, and/or cannot do so with low distortion. And this is not to mention the “compression” that normally occurs as the speaker plays louder and louder.

He obviously does not recognize “the FACT that distortion is approximately inversely proportional to efficiency and that uniform efficiency relates to flatness or uniformity of output with respect to frequency or so-called flat response”. (PWK’s words not mine).

If you’re using something reasonably efficient, say around 100dB/w/m or so, and inserting a high powered amplifier makes a positive difference to you, then I aver that something else other than the available power is the cause of the so-called “improvement” in sound quality.

And I have to wonder what does Michaelson mean by “ordinary high quality”? Isn’t that an oxymoron?

You guys tend to get very upset when other use non-horn speakers. Clause, no offense but not many people have speakers in their living room that are bigger that refrigerators.

To everyone, you may find this hard to believe, but there are people out there who have speakers that are not horns. Actually, high quality speakers, lots of them, all over the place. There are many out there that are less efficient than 100 db 1W/1M. I know, hard to believe. [:^)]

Anthony Michealson is known for boasting a lot about his equipment, but that said, he makes OUTSTANDING equipemnt that is typically less expensive that others of the same quality (mass production, use the same case for many pieces of equipment, etc).

He is also british and speaks differently than Americans, and the attempt to make arguments on his word choice is just plain silly. To turn the table, your statement that a "reasonably efficient speaker" is around 100 db is simply wrong. An extremely small percentage of speakers are 100 db efficient and almost all are horns. So are all speaker unreasonable because they are less efficient?

Lets try another one:

"He obviously does not recognize “the FACT that distortion is approximately inversely proportional to efficiency and that uniform efficiency relates to flatness or uniformity of output with respect to frequency or so-called flat response”. (PWK’s words not mine)."

Musical Fidelity (Michaelson's company) does not make speakers, so how do you come to this conclusion? He is making a product to drive speakers that have normal efficiencies. He cannot control how much power a speaker needs to hit a required volume, he just makes amps to drive them. It is also commonknowledge among owners of "inefficient speakers" like B&W, Wilson, etc. that you need very big amps. Check out audiogon and count how many amps are over 300 wpc, quite a few. I also guess that speaker manufacturers do recognize the above and have worked around it as most high end speakers are in the 87 to 92 db range and have much less coloration than K Horns and more detail.

"ordinary high quality" is not incorrect either. I read this as a high quality speaker that has an expected imedence and load. Many high quality speakers have very difficult loads and require a lot of power. I assume that this is what he means.

"The problem with his “beliefs” is that by the time a speaker of this low sensitivity approaches life-like sound levels in any reasonably good sized room with proper acoustical treatments, the speaker literally can either no longer absorb the amount of power required to produce the louder sound levels without destructing, and/or cannot do so with low distortion. And this is not to mention the “compression” that normally occurs as the speaker plays louder and louder."

Just plain wrong. My "inefficient" speakers play very loud if required (not 118 db like my old K Horns but I never listened that loud as I like my hearing). I have 700 wpc monoblocks driving them ( I had 900 wpc channel before) and they simpyl get louder. The soundstage does not break up or get bigger, and they do not have an extreme change in tone as K Horns do (and Yes, I had K Horns and Belles and they change tone with increased volume). You also assume that speakers are not designed to dissipate heat and handle the power expected to be driving them. My speakers are rated at 1000 wpc and the woofers have huge magnets and look more like aircraft parts than home audio. I think that the engineers knew what they were doing, and these woofers are definately not $150 EV woofers. My subwoofer is a JL Audio F113. That driver also does not fall into your description and it is built like a tank.

Not intended to be a personal attack here. If he said that horn speakers need 500 wpc I would say he is incorrect, but his assumptions do appear correct.