Floorstanders & low power amps?

[admin_exported]

I see in most reviews that “budget” lower power amps, lets say Rotel RA-04 (40W) and Marantz PM6002 (45W) for example, are typically paired with standmounts (MS Mezzo2s and B&W 685s being good examples of the breed). This may be a stupid question, but why not floorstanders, the likes of MA BR5s or KEF iQ5SEs, or equivalent?

I accept that price for price standmount speakers are probably superior to similarly priced floorstanders, but if aesthetics, more bass, etc were important criteria would floorstanders be a realistic option, or are these amps simply underpowered?

I see that iQ5SEs and BR5s specify power requirements of 15 to 130W and 30 to 120W respectively. So, I assume that a small amp would do the job.

This is where I get confused. Comparing the Mezzo 2s (120W, 89dB) and the BR5s (120W, 90dB) with the same max power handling, wouldn’t the BR5s with their higher sensitivity be easier for a small amp to drive? Or, am I missing something here?

 

[the record spot]

This throws me to a degree as well, however, I put an old NAD 3020A amp onto my current Mission 752 floorstanders, thinking it might be a little muted, but worth trying, and it drove them fine. Admittedly, the 3020 is conservatively rated at 25wpc, but I'd suggest that is on the slim side.

As long as you don't have a wild imbalance (e.g. Eastern Electric Minimax amp with speakers which can't accommodate an 8wpc amp - which the EE is) then you'll be fine. Otherwise, you risk damaging the amp or speakers.

 

[SteveR750]

Might have more to do with system matching from a price point of view. In the good old days of vinyl, then big floorstanders with their attendant extended LF would upset many a budget turntable, so matching stuff up was critical

 

[Anonymous]

Either way, I would always recommend buying an amp rated at least half the speaker power output. This prevents signal clipping. In other words, the amp being overdriven, creating sound waves that are distorted. I know this from experience, and from blown speaker cones in the past. Playing music at loud volumes put too much pressure on the amp, and knackering my speakers.

An amp of 25wpc playing through speakers rated 150w will never reach full potential. Its like having a ferrari limited to 80mph...not using its full potential...i think you get my drift now

 

[plastic penguin]

ScottH:

Either way, I would always recommend buying an amp rated at least half the speaker power output. This prevents signal clipping. In other words, the amp being overdriven, creating sound waves that are distorted. I know this from experience, and from blown speaker cones in the past. Playing music at loud volumes put too much pressure on the amp, and knackering my speakers.

An amp of 25wpc playing through speakers rated 150w will never reach full potential. Its like having a ferrari limited to 80mph...not using its full potential...i think you get my drift now

In the main, I think you're right. However, pairing floorstanders with a low powered amp is better, because, generally, floorstanders have higher db. My 40 watter has no problems powering my RS6's (91db), unless you need to play it at wall-shaking levels, then the power issue, obviously, comes into play.

If you do plump for stand mouted monitors I would suggest a speaker of no less than 89db.

 

[Anonymous]

Thanks for the advice guys. By way of example and clarification, I recall a What Hi-Fi review not too long ago recommending a pairing of the Marantz PM6002 (45W) amp with the standmount Mezzo 2s (120W, 89dB). Not quite half the power, but probably near enough.

If What Hi-Fi is comfortable recommending this pairing, can I therefore assume (ignoring specific system matching) that the Marantz amp would be equally comfortable driving the floorstanding BR5s with the same power rating of 120W? In fact, I guess the BR5s will be easier to drive given their 90dB higher sensitivity.

In conclusion, does this mean that my standmount vs floorstander question is a non issue as long as power ratings are kept within reason?

My question originates from my need to find replacement speakers to pair with my old Rotel RA935BX amp (40W and no tone controls). I will replace the amp in due course. So far considerations are B&W 685, MS Mezzo 2, MA BR2 standmounts, and KEF iQ5SE and MA BR5 compact floorstanders. It has been suggested that the MA BR2 and BR5s may be a little harsh at the top end with this particular amp, but I need to audition. I would like decent bass and room filling sound, at moderate volume, for a 5m x 5m room. Any suggestions?

 

[Andrew Everard]

Just to do some clarification on the whole thread...

- There's no such thing as speaker power output - it's power handling. In other words the range of amplifier outputs the speaker is designed to be used with.

- As long as your amp is at least as powerful as the minimum figure given by the speaker manufacturer, you should have no problems.

- You're much more likely to damage your speakers by using them with an amp that's too feeble rather than one with more power than the rated maximum quoted by the speaker manufacturer.

- Yes, sensitivity plays a major part in amp/speaker matching, and yes floorstanders tend to have higher sensitivity and are thus able to be driven by amps of less power.

- Bear in mind that speakers don't just keep on getting louder as you sling more amp power at them: they all have a finite maximum sound pressure level, limited by the amount of cone excursion possible.

- Also bear in mind that it's unlikely you'll ever be using the full power of your amp at normal listening levels: a few Watts is all that's needed to deliver pretty solid listening levels, and the rest is almost all there for dynamic headroom.

 

[SteveR750]

and perhaps one more point to Andrew's list is that doubling the power output = +3dB increase. Doubling the perceived volume = +10dB which is quite a lot of power required. In absolute listening loudness levels, there is not much between a 40w amp and a 140w amp into the same speakers, the higher powered amp simply has a greater current capacity to better handle transient peaks.

NAD's soft clipping is so very useful - it means you can simply turn the thing up to 11 without any fear of melting your tweeters! The ultimate student party amp!

 

[Andrew Everard]

Indeed, Mr 750 - meant to include that one but got momentarily distracted here in the office and hit the post button meaning to come back to it, but you know how these things are...