Confused about Pairing Speakers with the Right Amp/Stereo Wattage

[62caddy]

Good comments and they certainly help to clear things up a bit. I do understand that a jump from, say, 45 watts to 50 watts is negligible. Would there be ANY benefit if I went from my current 44 watts (on a new Onkyo a-9010) to 65 watts (on a Kenwood KA-7300 I’m currently eyeing)?

65 watts only provides 1.7 dB acoustic advantage over 44 watts which isn't very much worth talking about. With speakers of 86 dB sensitivity, you may want to consider a more significant upgrade in output capability - something on the order of 100 wpc or better.

 

[spark1]

From a power standpoint, negligible. Can't speak to relative sound quality.

 

[Djcoolray]

If a person is running a pair of speakers in the sensitivity range of 82db-86db, they can be pushed allot harder with a more powerful amp. With speakers of a sensitivity between 88db-105db the extra power does not make the sound fuller and there is no problem with distortion. I run a pair of 400 watt tower speakers with the sensitivity of 105db with a 160 watt amp and the volume hardly ever goes past the twelve o’clock position. The sonics of the soundstage is detailed within wondrous separation from front to the rear instrumentals.

Also, there is a reason why so many people are parting out their speakers on eBay and Amazon.

 

[rotobadger]

65 watts only provides 1.7 dB acoustic advantage over 44 watts which isn't very much worth talking about. With speakers of 86 dB sensitivity, you may want to consider a more significant upgrade in output capability - something on the order of 100 wpc or better.

Ok, thanks. I’m reading up on Watts to Decibels but it’s a bit over my head. Generally, however, I do understand the concept of the need for exponential power for significant gains in levels. Generally.

I guess, another way of putting it is that I started this thread with the though of a kenwood KR 9600 (160 watts) but was worried that was overkill for my KLH 5s.

Would maybe 85 watts be a “sweet spot”?

Also, I was liking the KA 7300/KT 7300 combo look but don’t want to spent the money just for eye candy. Would like a sound benefit as well.

 

[WaynerN]

Clipping is flat lining a sine wave, the output transistors are maxed. The flat line on an oscilloscope is DIRECT CURRENT! So, that means the speakers are getting the juice, they are just not moving. When this happens, the voice coil heats up (because it can't get rid of its energy), and then ultimately, starts to turn plasmatic and warp, sometimes accompanied with smoke and fire. This is called now days (being politically correct), as speaker abuse.

 

[spark1]

You can use a 1000 watt amp or a 5 watt amp.

The upside to the bigger amp is that you will never clip the signal. The downside is that you will have to use your ears to recognize when you are starting to push the speakers to their limits, and use your hand to control the volume (voltage drive) accordingly.

The smaller amp will almost assuredly be clipping if you decide you want to crank up the tunes.

Generally, assuming the amp is not running into clipping, power rating has little to do with sound quality.

Bottom line, you need an amp that will not clip when driving your speakers to the loudest level at which you will ever want to listen, and speakers which can handle the power required to do so.

Be aware that 160 vs 85 watts = 3dB in sound pressure (loudness). 3dB is generally considered to be the SMALLEST change in loudness to be clearly noticeable.

 

[toxcrusadr]

160W is not overkill if those are indeed 86 db speakers. One thing to also keep in mind is that if you go right to a nice powerful amp, you won't have to wish you had one later.

Side note: literally rolled my eyes when this thread turned into a debate about distortion and clipping. Let's keep in mind the OP asked a simple question and although he may want to go there at some point, this is not only way beyond the scope here, but it's been discussed at length in other threads. Just my two cents.

 

[spark1]

160W is not overkill if those are indeed 86 db speakers. One thing to also keep in mind is that if you go right to a nice powerful amp, you won't have to wish you had one later.

Side note: literally rolled my eyes when this thread turned into a debate about distortion and clipping. Let's keep in mind the OP asked a simple question and although he may want to go there at some point, this is not only way beyond the scope here, but it's been discussed at length in other threads. Just my two cents.

Determination of power requirements is inexorably related to clipping, and clipping is an important variable in sound quality.

 

[shelly_d]

Let's add a bit more clarity to dB's and sound level for you.

First, an average sound level of 85dB is loud enough to need two people standing next to each other have to shout to each other to be heard. Changing the sound level by 3 dB will be perceived as a small volume change by most people. Anything less then that is heard but is misidentified as somehow being fuller or richer or thinner or tinnyer or some other subjective description that is not volume. That change equates out to either doubling or halving the power needed from the amp. A 10dB change in volume is perceived as twice as loud or half as loud. This is a change in power by a factor of 10. So a change from 55 dB to 65 dB needs 10 times the power.

The way you compute this is to use power ratios. Using a scientific calculator (available in Windows, open the calculator App, click view and then select Scientific) take the power rating of the larger amp and divide it by the smaller one. Then take the Log of that number and then multiply that value by the number 10. This comes from the definition of the decibel:

dB = 10 * Log(P1/P2)

Using this method you can compare how much extra volume a more powerful amp will give you over the one you use now.

There is a whole lot more to using this where amps and speakers are concerned but I don't want to overwhelm you with all of that right now.

Now to your original question. There is no real sweet spot matching speaker power ratings and amp power. There is only a sliding scale that must be judged to your listening habits. The rule to follow is that you want enough power so that at a musical peak or crescendo won't drive the amp into clipping at your loudest preferred listening level. Once you have that level of power, it devolves into considerations of sound quality and what you like. That issue is again, beyond the scope of what I will get into here.

I hope this helps some, even though it is not a definitive answer. If you want more help with the math of the dB and volume I will be glad to help with further posts.

Shelly_D

PS: The only time an amp might be too powerful for a pair of speakers is when the speakers are so sensitive and the amp so powerful that even turned fully down you can audiblebly hear the noise of the amp through the speakers. That is an extreme situation unlikely to happen as long as you use those speakers, no matter what amp you choose. If you like the sound of the Kenwood, go for it.

 

[62caddy]

Ok, thanks. I’m reading up on Watts to Decibels but it’s a bit over my head. Generally, however, I do understand the concept of the need for exponential power for significant gains in levels. Generally.

I guess, another way of putting it is that I started this thread with the though of a kenwood KR 9600 (160 watts) but was worried that was overkill for my KLH 5s.

Would maybe 85 watts be a “sweet spot”?

Also, I was liking the KA 7300/KT 7300 combo look but don’t want to spent the money just for eye candy. Would like a sound benefit as well.

The only benefit of extra power capacity is the ability to play louder/resolve musical peaks at a higher level without distorting/clipping than a lower power amplifier. Additional power in of itself carries no inherent sonic benefit otherwise.

This of course is a separate issue from other sonic differences that may exist between various amplifiers having nothing to due with power differences. Simply because one amplifier is more powerful does not automatically mean it will perform better than a lower powered amplifier and visa versa.

Also, the older the equipment, the greater the chance it will need repairs which is another factor. It all boils down to whether your present unit has sufficient power for the speakers at the volume levels you customarily enjoy.

 

[sax6]

You'll be OK with a, let's say, 100 watts per channel amp... as long as there is no booze involved
or booze affected friends near the volume knob.

Otherwise, you'll be fine... use judgement... booze alters judgement.

 

[Grenadeslio]

Good comments and they certainly help to clear things up a bit. I do understand that a jump from, say, 45 watts to 50 watts is negligible. Would there be ANY benefit if I went from my current 44 watts (on a new Onkyo a-9010) to 65 watts (on a Kenwood KA-7300 I’m currently eyeing)?

Yes, the KA7300 is something special. Outstanding phono section, great preamp, true dual mono power supply, incredible build quality. Notice the clean architectural layout.

 

[toxcrusadr]

Dang that is sexy inside!

 

[Grenadeslio]

Also, I was liking the KA 7300/KT 7300 combo look but don’t want to spent the money just for eye candy. Would like a sound benefit as well.

Sure it's eye candy, especially with the handles lol. You just described my living rm system, but it's not all about the look, these integrateds are highly sought after and rather rare.

All that said, I'm currently using my 7300 as a pre only with one of my Belles I amplifiers doing the heavy lifting. That's one of the sweet things about this amp, it allows adding a dedicated power amp later on if you decide to upgrade but want to keep your Kenny. Yes the Belles sounds better, it should, it was more expensive and didn't include an awesome preamp along with it's power amp like the Kenny does.

Here are some pics.

The system driving AR58s.


The Belles I

 

[shelly_d]

Good comments and they certainly help to clear things up a bit. I do understand that a jump from, say, 45 watts to 50 watts is negligible. Would there be ANY benefit if I went from my current 44 watts (on a new Onkyo a-9010) to 65 watts (on a Kenwood KA-7300 I’m currently eyeing)?

If you went to anything less then 90 watts per channel, you would not perceive any increase in volume. If the new device is anything less then 90~100 watts per channel, consider only the quality of the sound, not the power output. There is not enough of it to increase volume levels noticeably.

 

[Grenadeslio]

Dang that is sexy inside!

Yes it is, I changed the picture for a larger so you could drool even more lol.

 

[Grenadeslio]

If you went to anything less then 90 watts per channel, you would not perceive any increase in volume. If the new device is anything less then 90~100 watts per channel, consider only the quality of the sound, not the power output. There is not enough of it to increase volume levels noticeably.

Not all amps of similar "stated" output are created equally.

 

[rotobadger]

Let's add a bit more clarity to dB's and sound level for you.

First, an average sound level of 85dB is loud enough to need two people standing next to each other have to shout to each other to be heard. Changing the sound level by 3 dB will be perceived as a small volume change by most people. Anything less then that is heard but is misidentified as somehow being fuller or richer or thinner or tinnyer or some other subjective description that is not volume. That change equates out to either doubling or halving the power needed from the amp. A 10dB change in volume is perceived as twice as loud or half as loud. This is a change in power by a factor of 10. So a change from 55 dB to 65 dB needs 10 times the power.

The way you compute this is to use power ratios. Using a scientific calculator (available in Windows, open the calculator App, click view and then select Scientific) take the power rating of the larger amp and divide it by the smaller one. Then take the Log of that number and then multiply that value by the number 10. This comes from the definition of the decibel:

dB = 10 * Log(P1/P2)

Using this method you can compare how much extra volume a more powerful amp will give you over the one you use now.

There is a whole lot more to using this where amps and speakers are concerned but I don't want to overwhelm you with all of that right now.

Now to your original question. There is no real sweet spot matching speaker power ratings and amp power. There is only a sliding scale that must be judged to your listening habits. The rule to follow is that you want enough power so that at a musical peak or crescendo won't drive the amp into clipping at your loudest preferred listening level. Once you have that level of power, it devolves into considerations of sound quality and what you like. That issue is again, beyond the scope of what I will get into here.

I hope this helps some, even though it is not a definitive answer. If you want more help with the math of the dB and volume I will be glad to help with further posts.

Shelly_D

PS: The only time an amp might be too powerful for a pair of speakers is when the speakers are so sensitive and the amp so powerful that even turned fully down you can audiblebly hear the noise of the amp through the speakers. That is an extreme situation unlikely to happen as long as you use those speakers, no matter what amp you choose. If you like the sound of the Kenwood, go for it.

Excellent read, Shelly. Thanks. I'm starting to understand the math a bit.

Also, thanks for the replies. All of you have really helped make this process enjoyable and educational!

 

[rotobadger]

Sure it's eye candy, especially with the handles lol. You just described my living rm system, but it's not all about the look, these integrateds are highly sought after and rather rare.

All that said, I'm currently using my 7300 as a pre only with one of my Belles I amplifiers doing the heavy lifting. That's one of the sweet things about this amp, it allows adding a dedicated power amp later on if you decide to upgrade but want to keep your Kenny. Yes the Belles sounds better, it should, it was more expensive and didn't include an awesome preamp along with it's power amp like the Kenny does.

Here are some pics.

The system driving AR58s.
View attachment 1320347

The Belles I
View attachment 1320348

Ok, that picture you posted is NOT helping my situation! Now I REALLY want to add the Kenwood. It looks amazing in that setup!

So, aside from my power questions, the 7300 has a nice sound? I'm currently using a Project Tube Box S2 for a preamp and think I might want to keep that in the chain. Of course, if I do that, I will not be using the 7300's pre, only the Aux. Not to digress but the Tube Box S2 does not use opamps and is very nice and "tube-y" sounding. Wonder how it'd sound with the Kenny. Also, if I do get the 7300, I will have the add the KT7300 because it looks so cool!

 

[Grenadeslio]

Ok, that picture you posted is NOT helping my situation! Now I REALLY want to add the Kenwood. It looks amazing in that setup!

So, aside from my power questions, the 7300 has a nice sound? I'm currently using a Project Tube Box S2 for a preamp and think I might want to keep that in the chain. Of course, if I do that, I will not be using the 7300's pre, only the Aux. Not to digress but the Tube Box S2 does not use opamps and is very nice and "tube-y" sounding. Wonder how it'd sound with the Kenny. Also, if I do get the 7300, I will have the add the KT7300 because it looks so cool!

It's also a great tuner with the same chassis build quality of the amp, I know because that's what the amp is sitting on.