What rules of thumb should be considered matching any loudspeaker to amplifier?

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Hi! I was wondering if there were any golden rules of thumb to be kept in mind for synergy previous to purchasing amplifier for loudspeakers or vice versa.

Thanks!

I can think of the following rules - with several exceptions of course:

1. Impedance match: If you have autoformers - one of the outputs should match the loudspeakers impedance - and the impedance swings should not be more than +- 1 impedance in order to avoid hights rolling off. Hence, the there are some limitations for selecting the loudspeakers. There are, of course, exceptions.. :)
2. If you have very transparent speakers, like Martin Logans, expect the loudspeakers to reveal all the good and all the bad sounds from the record. You probably should have some "smoothing" out gear (tubes in the pre-amp for instance). You may also have a tube main amplifier, which is a contradiction to rule nr.1 :)
3. If you have a dynamic speakers which is not very transparent you may consider more analytical amplifier, such as Hegel for instance.
4. An SS amp should double the effect/W from 8 to 4 ohms, and the same from 4 to 2 ohms if you speaker has impedance swings like ML. This is not crucial if you have a stable impedance for you speakers.
5. Try to avoid several stages in the loudspeaker that is hampering the signal to reach the loudspeakers. A lot of gear have autoformers - both on the amp side and on the loudspeakers side. Try to minimize all these steps (again - I can think of several exceptions)
6. Avoid "harsh" loudspeakers on "harsh" amplifiers and vice versa.
7. Decide if you want the best hi-fi detailed gear or a musical gear :)
8. Listen to the amplifiers and the loudspeakers first.
 
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I can think of the following rules - with several exceptions of course:

1. Impedance match: If you have autoformers - one of the outputs should match the loudspeakers impedance - and the impedance swings should not be more than +- 1 impedance in order to avoid hights rolling off. Hence, the there are some limitations for selecting the loudspeakers. There are, of course, exceptions.. :)
2. If you have very transparent speakers, like Martin Logans, expect the loudspeakers to reveal all the good and all the bad sounds from the record. You probably should have some "smoothing" out gear (tubes in the pre-amp for instance). You may also have a tube main amplifier, which is a contradiction to rule nr.1 :)
3. If you have a dynamic speakers which is not very transparent you may consider more analytical amplifier, such as Hegel for instance.
4. An SS amp should double the effect/W from 8 to 4 ohms, and the same from 4 to 2 ohms if you speaker has impedance swings like ML. This is not crucial if you have a stable impedance for you speakers.
5. Try to avoid several stages in the loudspeaker that is hampering the signal to reach the loudspeakers. A lot of gear have autoformers - both on the amp side and on the loudspeakers side. Try to minimize all these steps (again - I can think of several exceptions)
6. Avoid "harsh" loudspeakers on "harsh" amplifiers and vice versa.
7. Decide if you want the best hi-fi detailed gear or a musical gear :)
8. Listen to the amplifiers and the loudspeakers first.

Much better than mine.lol
 
Hola Chicos...but Julian, the final judge are your ears, no matter what, right? There are a lot of brands on the market today with outstanding performance and sound quality. You do not need to know their specs, to suite your liking. If an amplifier is not good for your speakers, then your ears will tell right away. If you do like a lot what you are listening, and your feet is moving along with the music, then you are with the right gear, no matter if the amp type is tube, SS or D. You have a lot of information through the non profit reviewers, or better say, the ones that say the truth about the product that they are reviewing, you can see pics of the printed circuit boards inside, and the quality built, and you can use the common sense as a guide for your decision. Some designs for amplifiers do not like the impedance of the electrostatic panels of Martin Logan...you can tell when they are not driving the panels right, you get distortion or roll of the highs...easy thing to tell. On others, will show you the stage, (your ears working here), is it a wide stage and has depth 3D?, the size of the instruments (your ears working here), do you have the size of a violin versus the size of a piano, playing together? the air between the instruments (your ears working here), are the instrument(s) played with air between them or do you have a mess and trouble to tell? the dynamics of the overall sound (your ears working here), is it fun to listen the percussion instruments? what about the wind instruments, like a sax or a trumpet?, the glare at the voice(s) (your ears working here) are you listening a clear voice or a sored throat that sounds like a frog singing? Is the timbre of the instrument(s) right?, can you tell the difference between a viola and a violin?... These, and of course are more, are the questions that you should ask yourself when you are evaluating an amplifier or any other audio component for your system.. specs are a guides, but will not tell you if the amp will drive your speakers with your sounding needs. Trust your ears! They are final judge. Happy listening.
 
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"Where there is much desire to learn, there of necessity will be much arguing, much writing, many opinions; for opinion in good men is but knowledge in the making".
( John Milton 1608-1674; English poet )

Thanks! Roberto, Redux and InterMechanico for detailed, clear and educational individual experience insights. Helps to determine basis for selecting synergistically matching amplifier and loudspeakers. Very helpful and definitely knowledge in the making.
 
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Hola Chicos...but Julian, the final judge are your ears, no matter what, right? There are a lot of brands on the market today with outstanding performance and sound quality. You do not need to know their specs, to suite your liking. If an amplifier is not good for your speakers, then your ears will tell right away. If you do like a lot what you are listening, and your feet is moving along with the music, then you are with the right gear, no matter if the amp type is tube, SS or D. You have a lot of information through the non profit reviewers, or better say, the ones that say the truth about the product that they are reviewing, you can see pics of the printed circuit boards inside, and the quality built, and you can use the common sense as a guide for your decision. Some designs for amplifiers do not like the impedance of the electrostatic panels of Martin Logan...you can tell when they are not driving the panels right, you get distortion or roll of the highs...easy thing to tell. On others, will show you the stage, (your ears working here), is it a wide stage and has depth 3D?, the size of the instruments (your ears working here), do you have the size of a violin versus the size of a piano, playing together? the air between the instruments (your ears working here), are the instrument(s) played with air between them or do you have a mess and trouble to tell? the dynamics of the overall sound (your ears working here), is it fun to listen the percussion instruments? what about the wind instruments, like a sax or a trumpet?, the glare at the voice(s) (your ears working here) are you listening a clear voice or a sored throat that sounds like a frog singing? Is the timbre of the instrument(s) right?, can you tell the difference between a viola and a violin?... These, and of course are more, are the questions that you should ask yourself when you are evaluating an amplifier or any other audio component for your system.. specs are a guides, but will not tell you if the amp will drive your speakers with your sounding needs. Trust your ears! They are final judge. Happy listening.


Agreed!!! However, it is easier to find candidates for benchmarking if you follow some rules of thumb regarding the specs :)
 
Yup, specs acts like a good guide, but one of the worst specs, or better say, conservative specs, are the Conrad Johnson amplifiers, and are one of the best sounding amplifiers of the whole world. And this is not only me with this statement. These are some specs the LP-125sa power amp:
Power:
LP125sa - 125 Watts per channel from 30 Hz to 15 KHz at no more than 1.5 % THD or IMD, both channels driven into 4 ohms (also available connected for 8 or 16 ohm loads)
LP260m - 270 Watts from 30 Hz to 15 KHz at no more than 1.5 % THD or IMD, driven into 4 ohms (also available connected for 8 or 16 ohm loads)

Just reading about the distortion specs, one of the most seeking specs, you will find that many power amplifiers with .000zip distortion specs, they do sound like sh*t! And your ears tell you that right away.
So again, what tells us if something is singing right, are our ears. Trust them, not the specs. Happy listening!.
 
The Lector CD player which is a superb player measures as a broken CD player
 
From an amplifier's point of view not all loudspeakers are benign loads (think true ribbons and electo-statics). Many reasonable amplifiers are optimized for rather benign loads and don't do well with more demanding loudspeakers. John Atkinson at Stereophile often covers this point in his test measurements.
 
Hola. Some time ago, in the 90s, Martin Logan had an exclusive customers list. In this list, many high-end companies were using Martin Logan as a tool design. I recall Mark Levinson, Audio Research, Conrad Johnson, Classe, Krell, Bryston, Blu Circle, Parasound, Pass Labs, Spectral, Cary Audio, McIntosch, Sutherland Audio, to name a few. We do know that ML is not very easy to drive, and the reason why the manufactures use ML as a tool design. My point and statement is: final judge of the sound quality of your system is your ears! No matter what specs your amplifier might have, listening it, your ears are the responsible of your decision, not the specs. Happy listening!
 
I can think of the following rules - with several exceptions of course:

1. Impedance match: If you have autoformers - one of the outputs should match the loudspeakers impedance - and the impedance swings should not be more than +- 1 impedance in order to avoid hights rolling off. Hence, the there are some limitations for selecting the loudspeakers. There are, of course, exceptions.. :)

Good luck, very few speakers stay within one ohm of their stated impedance, MLs being a great example.

2. If you have very transparent speakers, like Martin Logans, expect the loudspeakers to reveal all the good and all the bad sounds from the record. You probably should have some "smoothing" out gear (tubes in the pre-amp for instance). You may also have a tube main amplifier, which is a contradiction to rule nr.1 :)

Maybe and maybe not, pick neutral sources and you can get very detailed amps w/o tipping into that gritty/grainy, hyper-detailed sound some audiophiles seem to love. Not me personally, I'll always take beauty over excessive detail.

3. If you have a dynamic speakers which is not very transparent you may consider more analytical amplifier, such as Hegel for instance.

Buy better speakers!

4. An SS amp should double the effect/W from 8 to 4 ohms, and the same from 4 to 2 ohms if you speaker has impedance swings like ML. This is not crucial if you have a stable impedance for you speakers.

Again, good luck, amps that truly double will cost a fortune and may or may not sound better.

5. Try to avoid several stages in the loudspeaker that is hampering the signal to reach the loudspeakers. A lot of gear have autoformers - both on the amp side and on the loudspeakers side. Try to minimize all these steps (again - I can think of several exceptions)

Seems reasonable, but how many manufacturers are big on autoformers, McIntosh excepted, and their amps are some of the best I've heard.

6. Avoid "harsh" loudspeakers on "harsh" amplifiers and vice versa.

Yep!

7. Decide if you want the best hi-fi detailed gear or a musical gear :)

You can have both, but it'll cost you. These two things are not mutually exclusive. The system I heard at The Show, Newport with the Kronos LE TT, Audionet preamp and monoblocs with K-S cables and, YG Hailey loudspeakers was both, with no listener fatigue, gobs of realistic detail and a price tag that you could buy a BIG house for in most of the country.

8. Listen to the amplifiers and the loudspeakers first.

Yep, preferably in your own room with your own sources.
 
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And sometimes, things that on the surface seems to not match, actually end up making a lot of sense giving excellent sound. Case in pint: I just bought a pair of single ended triodes to drive my Vantages; they are superb!

Of caurse, it only works because these triodes are a bit special: 6c33 with a plate resistance of only 80 Ohms, thus making it possible to design an output transformer with suffiently low output impedance to avoid high-frequency roll-off.

Also, since Martin Logans are quite efficient (91 dB/Watt, 1 meter) despite being electrostats, a few Watts tend to go a long way. This is further enhanced by the limited 30-degree dispersion angle, which means that Martin Logans are closer to 3dB less SPL per double distance than the 6 dB per doubling distance for dynamic speakers.

So lets make a quick "back-of-envelope" estimation of the power required to get the same SPL in my sofa from a pair of dynamic speakers of, say, 87 dB/Watt/meter sensitivity as I get from my Vantages driven by an 18 Watt SET amp.

My sofa is roughly 4 meters from the speakers, so the SPL is 6 dB down from each speaker of which there are two. The SPL from a set of stereo speakers is roughly 3dB higher than from a single speaker. So from 1 Watt, I will in my sofa have an estimated SPL of 88 dB (91-6+3=88). 18 Watts is a bit over 2⁴ times 1 Watt, so with each doubling yielding a 3dB SPL increase, I will be able to get an estimated 88+(4*3) = 100 dB continous SPL in my listening position. Dynamic peaks, mind you, can be considerably louder, the 6C33 is famous for being able to deliver very high peaks indeed.

So how much amplifier power would I need to get to 100 dB continous SPL in my sofa with the 87 dB sensitivity dynamic speakers? Well, since SPL decrease by 6 dB with each distance doubling, I will get 87-12=75 dB from each speaker for 1 Watt. Since there are two, we add 3 dB (as before), resulting in a stereo SPL from 1 Watt in my sofa of 78 dB. To get to 100 dB, we need 22 dB more, each 3 dB requiring a doubling, so we would need (rounding 22 dB off to 21 for ease) 7 doublings, or 2⁷=128 Watts to get the same SPL in my sofa driving a pair of dynamic speakers of average sensitivity to the same level as my SET can drive my Martin Logans.

Note that this is due to a combination of sensitivity and radiation pattern. A dynamic speaker would need to have a 1-meter sensitivity of 97 dB to match the Martin Logan's sensitivity at my listening position of 4 meters. Not many speakers out there with 97 dB sensitivity. If your listening position is even further away than 4 meters, it gets even worse.
 
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Hi Bevensee,

Hard for me to judge the accuracy of what you state.

However i find it difficult to believe that from 1 watt i will in my sofa have an estimated Sound Pressue level of 88db ( 91-6+3=88).

What you may have at 1 watt will be a Sound Pressue level of -88db reading on your amplifier. A 2 db SPL.

Again i find hard to say since i am not an electronics expert.

What we need is an electronics experts opinion.

Please, Roberto we need your help.

Thanks for your valuable thoughts regarding the issue\thread.
 
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^ Typically a speaker will output 85-100dB with 1W power from amplifier, this is called sensitivity.
Sometimes manufacturers prefer to give a reading for voltage sensitivity which indicates how loud a speaker will play at certain voltage level, typically 2,83VAC which is same as 1W to 8ohm load. Actual power will then depend on speaker impedance 1W@8ohms, 2W@4ohms...

Doubling of output power will produce 3dB increase in SPL so 90dB/1W speaker will play at 100dB/10W, 110dB/100W and 120dB/1000W if it could :D
 
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^ Typically a speaker will output 85-100dB with 1W power from amplifier, this is called sensitivity.
Sometimes manufacturers prefer to give a reading for voltage sensitivity which indicates how loud a speaker will play at certain voltage level, typically 2,83VAC which is same as 1W to 8ohm load. Actual power will then depend on speaker impedance 1W@8ohms, 2W@4ohms...

Doubling of output power will produce 3dB increase in SPL so 90dB/1W speaker will play at 100dB/10W, 110dB/100W and 120dB/1000W if it could :D

Thanks very much MPS for the clarification. Reinforces what was said earlier by Bevensee.

Thanks, once again.
 
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Please take my calculation as nothing more than a "back-of-envelope" estimation. From my practical experience having owned various combinations of speakers and amplifiers, however, I would say that it matches quite well with what I experience. I certainly don't feel that I have less headroom than I did driving a pair of Vienna Acoustics (88 dB sensitivity) from a Vincent SP-T100 (200 W in 4 Ohms).

But this is all very room dependent. If the speakers are close to the side walls, the dynamic speaker will appear louder (but less focused). So in the end, I support Roberto: One needs to listen for oneself.
 
Yes, things will be somewhat different in actual room acoustic and also depending of the speaker construction or operating principle, there is a parameter called directivity http://www.mcsquared.com/speakers1.htm

Sensitivity or efficiency is measured in anechoic chamber because need for standard, room acoustic has too many variables to for standard measurement. You should take manufacture's readings as guideline only as ymmv.
 
Hola Chicos...and with my experience, both MPS and Bevensee are right with their statements. I am more with the reality and Bevensee is right as I said before.

Believe me this: once, I took my portable SPL to our National Theatre Concert Hall, to listen the Beethoven's 9th Symphony. I got a nice 7 center row seat, and the stage was so near to me, about 15 feet. At the highest passages, I got a measure of 93dB!. Never louder than that!, and there were over 160 musician(s) with the choir at the stage!. What a presence! Had never experienced anything like it! The kind of sound energy is different than the one that we get through our speakers.

And yes, one watt is one watt. I have a funny explanation regarding quality watts than quantity watts. We have percheons and ponies. Both are horses, but one percheon can pull 20 ponies. I know I am going to be nailed here. The percheon for me, is the quality watt amplifier, and your ears are the judge.

You do know that I prefer tubes. This is my liking. And some of you are with me on this. We have to take in count, all the parameters involved in our room. We all know that we have to treat the room for better quality sound, and to avoid the bad resonances usually by the standing waves. I have a dear friend who is nuts with measurements. He has everything in tools. You can see in graphics all what he is doing at his room...and I do not like it! I find his room lacking of fun...everything it too precise perhaps, but to my ears, I am saying no, no, no. The good thing, is that he is happy.

So, again, your ears are telling you what do you like and what you do not. Trust in them. Listen to live music, and try to emulate that sound in your home. The music is for enjoyment, right? And having the musician(s) playing for you, in your own place, is something that you are getting through your system. Do not play the music too loud. Yes I know, metallica! or hard rock music must be played loud...a reason why I do not listen that type of music. I like classical, jazz and lounge easy listening music. Unplugged! Vocals, solo instruments, you name it. I think I am out of the topic, but again the rule is: trust your ears!
Happy listening!
 
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