Matching Amp to Speakers

[Deutscher]

Hi guys,

Just wondering if there was a general rule to matching a amp and speakers?
Should you get an amp with the rated power of the speakers or abit higher?
I'm gonna get some Focal 6.5 K2 85RMS speakers, looking for an amp to match them, just not sure if I need 85RMS or 100RMS or watever. Thx guys.

[holdenboy]

Honestly, those are really great sounding speakers and i would give them atleast 100wrms. You can basically give them as much power as you want, but just be very careful when tuning the amp as clipping (distortion) at even 50wrms can potentially damage your speakers.

[Deutscher]

Honestly, those are really great sounding speakers and i would give them atleast 100wrms. You can basically give them as much power as you want, but just be very careful when tuning the amp as clipping (distortion) at even 50wrms can potentially damage your speakers.

I've heard only got reviews on them, just wondering, how many dB would these produce? By looking at RMS rating can you determine the volume? or has that nothing to do with it? I just want to be able to compare speakers somehow in volume... I know these speakers will be very good on SQ but in volume?

Edit: I own a pair of Type R Alpines which are rated at 75RMS (or 70.. cant remember), and I was looking for something louder. But 75 to 85 isnt much, I was looking at other speakers rated at 150RMS... which are around same price but everyone been saying for for Focals.

[wez]

If the amp is more powerful than the speakers, it is capable of blowing them up, but fuses in the speaker lines prevent this. It starts sounding like crap before it is at the stage of blowing the speakers, so provided you ease the volume up to test with a cd you are familiar with, you should be able to work out your max volume setting. For this purpose don't use music that is already distorted, like Death Metal; maybe use a symphony orchestra recording - you might be amazed how good it sounds cranked up.

If the speakers are rated too much higher (eg double) they might not sound at their best.


Try slow-blow 3amp fuses on the speaker lines if the speakers are 8 ohm, and 4amp if they are 4 ohm. To be on the safe side, you could use lower value fuses and see if they blow before you reach the volume you want. Inline fuse holders and fuses are really cheap, and a blown fuse is better than a blown speaker any day.

HOT TIP: An important spec. to check out when buying speakers is Sensitivity. 3dB more sensitivity gives the same volume as using double the power in the amp. The wattage of a speaker does not in itself tell you how much volume you will get.

[wez]

"just be very careful when tuning the amp as clipping (distortion) at even 50wrms can potentially damage your speakers."
That's right; if you overdrive the amp you can blow your speakers at lower than their rating; go the fuses just to be sure.

[Deutscher]

ok, my understanding is that, for 85rms prob look for 100-125rms amp? to give the amp headroom? even though you don't use it for full capacity. If you use a 85rms amp you would be pushing the amp to its limits which possible cause distortion and prob shorten the life.

So golden rule, look for an amplifier 1.5x the rms rating of the speakers?

Edit: I'm currently looking at the MB Quart DSC 4125 4channel amp, rated at 125W x 4.

[holdenboy]

Yep, youve basically got the idea. The MB Quart amp youre looking is good quality too. Just out of curiosity, what are you planning to run off the rear channels?

[2LOUD2OLD]

If the amp is more powerful than the speakers, it is capable of blowing them up, but fuses in the speaker lines prevent this. It starts sounding like crap before it is at the stage of blowing the speakers, so provided you ease the volume up to test with a cd you are familiar with, you should be able to work out your max volume setting. For this purpose don't use music that is already distorted, like Death Metal; maybe use a symphony orchestra recording - you might be amazed how good it sounds cranked up.

If the speakers are rated too much higher (eg double) they might not sound at their best.


Try slow-blow 3amp fuses on the speaker lines if the speakers are 8 ohm, and 4amp if they are 4 ohm. To be on the safe side, you could use lower value fuses and see if they blow before you reach the volume you want. Inline fuse holders and fuses are really cheap, and a blown fuse is better than a blown speaker any day.

what are you on about, there is absolutely zero reason to put a fuse on your speaker wire

there is nothing wrong with more power to your speakers, as mentioned so long as the gains are set correctly and the amp isnt clipping you'll be fine. more power is always a good thing, i like plenty of power on my midbass, it tends to open the sound right up, it also means your amp doesnt have to work as hard

[holdenboy]

LOL, yeah i was wondering about the fuse thing to......but each to their own i suppose.

[Deutscher]

Yep, youve basically got the idea. The MB Quart amp youre looking is good quality too. Just out of curiosity, what are you planning to run off the rear channels?

Well atleast you think the amp is good! That's a start. It's not actually for me, It's for my missus, I'm just getting her system for her. I'm not sure what I'll do, If I will just get 2 sets of focals, one for the front and one in back back or do what I'm doing to my car and having both sets at the front.

Gotta ask her. I was just thinking a 4 channel would be more beneficial instead of getting a 2 channel now and another 2 channel later.

[holdenboy]

In my opinion the focals are a little bright sounding (abit too much treble). But thats just my opinion, and as you know everyones tastes are different.

Will the system incorporate a subwoofer?

[Deutscher]

In my opinion the focals are a little bright sounding (abit too much treble). But thats just my opinion, and as you know everyones tastes are different.

Will the system incorporate a subwoofer?

Yes, 12" Hifonic Olympus 2412, 2400RMS/4800Peak. Running off a Hifonic Brutus 2608d amp, 2600RMSx1

[Deutscher]

Uhh... guys...
change of plan... thinking about going with the MTX THUNDER TXC 6.1 component set (150RMS).

Was wondering if should get the:
MB QUART DISCUS DSC450 4 CHANNEL, which is 200RMS x 2 (bridged) or
MB QUART DISCUS DSC2150 2 Channel, which is 150RMS x 2 or
(don't think so) KENWOOD KAC-7204 2-CHANNEL, which is 170RMS x 2.

The 4 channel would give me headroom and not to push the amp to it's limits, which I think would be the best idea. But not too sure about the bridged part... don't know if components should be bridged or what the CONS are for it.

Reason I put the kenwood in was because of the 170RMS, I was thinking 150RMS wouldn't be enough to power the 150RMS speakers easily.

[holdenboy]

Luke0011 mentioned a while ago that bridging a 4 channel amplifier results in a reduction of channel separation. Basically theres a smaller difference in between the left and right channels. I dont know whether you'll notice the difference or not, but its just something to consider.
Anyway 150wrms will be fine for a front stage, even though thats what the speakers are rated at they'll still go hard! Plus i'd prefer MB Quart over Kenwood anyday

[Deutscher]

Luke0011 mentioned a while ago that bridging a 4 channel amplifier results in a reduction of channel separation. Basically theres a smaller difference in between the left and right channels. I dont know whether you'll notice the difference or not, but its just something to consider.
Anyway 150wrms will be fine for a front stage, even though thats what the speakers are rated at they'll still go hard! Plus i'd prefer MB Quart over Kenwood anyday

Ye, go MB Quart German engineered
Not fan of Kenwood. How do you mean channel seperation? I'll try to search about this. It's not frequency range or anything is it? you mean db volume difference? weird haha.

[holdenboy]

Basically bridging the channels reduces the difference in between left and right channels, making it less noticeable that one speaker is playing left and one is playing right sounds.....well thats the best way i can descibe it.

I personally run a 4ch amplifier (german too) bridged to run my front stage (feeding 150wrms to 60wrms speakers). I have unbridged the outputs and besides the obvious volume drop i cant hear any major differences. I havent got the most sensitive ears though, 145+ db does that haha.

If it really concerns you then message Luke0011 about it, he may be able to explain it further.

Oh yeah, remember RMS power ratings are just one of the specs you should take nto consideration when buying a set of speakers. Things like sensitivity, mounting depth (if applicable) and one thing i always regard high is the materials used (i.e. tweeter - soft / titanium / ribbon). Just a few more things to confuse you