Should we care about ohms & watts in amp and speaker matching these days?

[Sy101]

The What Hi*Fi? How To Video says "Mostamps will drive most speakers" and I know you want to have similar amp andspeaker impedance to ensure tone quality is at its best and you're not overheating the amp or under powering the speakers.

My question is should I be addressing a slight mismatch in my system below by upgrading to get a precise match this time ordoes it really not matter (within reason) these days?

Speakers

Monitor Audio Silver Series RS5 FloorstandingSpeakers

Nominal Impedance: 6 Ohms

Power Handling (RMS): 100 W

Recommended AmplifierRequirements (RMS): 40 - 100 W

Amp

Musical Fidelity X-150 Integrated Amp

Power: 105 Watts One Channelinto 8 Ohms (20dBW)

141Watts One Channel into 4 Ohms

 

[Andrew Everard]

No reason to - no electrical mismatch there...

 

[Anonymous]

Hi Andrew

My setup is - Marantz PM7001 (70W @8 ohms / 100W@4 ohms) + CD6003 + Quad 11L2 (85 W @ 6ohms)

Is clipping possible considering that Speaker output is more than amp output ?

Marantz amps i am told are generally under rated ....So my calculation here was that Marantz at 6 ohms should be

more than 85W and hence sufficient to drive Quad's without clipping . I generally dont play with the volume knob beyond 11'o clock position .

Pls share your exp with Marantz PM7001 and if they are capable of driving Quad's without any clipping .

 

[jockey.wilson]

COOLDUDE7808:

Is clipping possible considering that Speaker output is more than amp output ?

Marantz amps i am told are generally under rated ....So my calculation here was that Marantz at 6 ohms should be

more than 85W and hence sufficient to drive Quad's without clipping . I generally dont play with the volume knob beyond 11'o clock position .

Clipping has nothing to do with speaker output or max continuous output (in this case a quoted 85w). Clipping is where the amp reaches the absolute limit of the voltage that it can output, causing distortion. If you consider the output as a series of peaks and troughs (ie a sine wave), clipping occurs when the demand for a peak is greater than the amp can physically output; ie you turn the gain (volume) up too much, and/or the input to the amp is too great.

Most speakers will be able to accept dynamic peaks in excess of their continuous output. For example, my Dynaudios are only rated at 150 watts continuous, but can accept up to 1000 watts transient (dynamic) power.

Hope that makes sense?

FWIW, your Marantz should have no snags with the Quads.

 

[Anonymous]

thanks Wilson ....

my system lost some brightness in the past few days .....there was some amount of distortion at times in vocals ....but i did not lower the volume .........since Marantz has a protective circuit which will lower the volume automatically ..........this circuit never got activated .............so i thought it could be the recording .............i then assumed that maybe its the burn in phase (since all of them are new ) ............all said and done the quality of sound after one and half months of playing is not to my liking ............there is no distortion now ........but loss in brightness is a bit too much ........

so I have this feeling that speakers might have suffered from some amount of clipping ......maybe the tweeters ?. Hence I wanted to check .... given the specs of the amp and speakers ..if its possible?

Then I biwired the speakers ........sound has improved to some extent ..........i will give it some more time and then see ..........maybe i need to add some more power to my amp to drive my Quad's more effectively ?

 

[Anonymous]

I have the Quad 12L2, and they are not a bright sounding speaker. That said, the tweeter doesn't sound dull either. I think it's pretty close to ideal, at least for my tastes. I'm sure there are some that would prefer brighter.

I am no expert, but I've picked up some knowledge over the years. Speaker impedance comes into play when matching to an amp. You cannot really boil a speaker's impedance down to one figure, because the impedance varies greatly across the entire frequency band. Pull up an impedance graph and you'll see this. Lower impedances (below 6ohms) can tax an amp, especially when they occur in the bass/midbass. Lower impedances at higher frequencies do not tax an amp as much, because these frequencies are easier to generate. Smaller waves, and many occur at the tweeter, which is less mass for an amp to have to move than is a big woofer.

So impedance dips below 6 can start to tax an amp that's doesn't have a lot of current to provide, but it becomes especially a concern at dips to 4ohms or less. There is another aspect to consider, which is the phase angle (also plotted on an impedance graph). When you have a tough impedance level, if the phase angle isn't at 0 at that point, these two things make life extra tough on an amp, and you'd probably need an amp that has lots of power on tap.

Hopefully I can post this article, for anyone interested in learning about this stuff. It's simply an educational piece that I was referred to. Not another forum or anything like that. http://www.symphonysound.com/articles/tubefriendly.html