That “rule of thumb”

Speakers & Subwoofers
1

So while you’re trying to learn all you can about the lingo, and the jargon, and the slang, and the vernacular, while you’re trying to bone up on your vocabulary, and learn to tell the difference between an ohm and an amp, and why on earth would you want a pre amp if you’re just going to feed that into an amp anyway, you also inevitably run smack dab into some “rules of thumb”.

They tell you that “mono blocks sound better”?

Really? Better than what?

If I took an $800 stereo amplifier, which does well bridged as a a Monoblock, and bought ANOTHER identical $800 stereo amplifier, would running one to my left channel and the other to my right channel, would that sound BETTER than running a single $1600 stereo power amp?

Sure, I have no doubt it would sound better than the single $800 amp, but that’s not what you should measure such a setup against. We’re talking about spending $1600 on amplification, is the pair of $800 amps going to sound notably better than a single $1600 amp?

How far out does this scale? I’ve bumped into “bi-amping” a number of times, and keep reading the “rule of thumb” that running separate amps for each frequency sounds better -

Does running 2 amps as stereo, one for high frequencies and the other for low frequencies sound better than 1 by the same amount as running one for left and the other for right? Does $3,200 sound better spent on 4 amps at $800 each, so I can run an $800 amp to the left high, another to the left low, another to the right high, and finally to the right low?, or would a single $3,200 stereo amp sound just as good?

This is all, of course, assuming the speakers in question can take a proper bi-amp setup to begin with…

2

Single chassis stereo amplifiers presumably? Single chassis dual mono amplifiers to a lesser extent? Assuming they’re from the same brand and model/series of products? I guess in one sense, most often you’ll find that a mfg for their higher end lines go from stereo power amps to then monoblocks as their higher end option which can be one way to get that impression, but that’s only in one highly specific case where that could potentially consistently hold true.

Probably not, but all depends on the amplifiers, speakers, and rest of the chain as well. You also don’t have to run bridged, a more apples to apples comparison would be a single chassis stereo amp compared to a monoblock design amp, not bridging stereo amps. But considering your bridging scenario, could sound better (or actually potentially worse depending on the speaker you use), but you’d likely get more value from a higher end stereo amp (assuming from the same company, if you compare a very different stereo amp from a different company it really muddles things). Generally though you aren’t going for monoblocks and/or bridged for value (most of the time). Personally imo I wouldn’t go for bridged amps if I wanted monoblocks and would prefer a design meant as a monoblock from the ground up without bridging but that’s just me

Biamping is another complicated topic that ends up being very situational, personally I’ve only really found it worthwhile if you were forced to use vintage electronics, or really really really (and I mean really) high up and that was the only option. Personally I’m not too partial to it since often it ends up being more hassle than it’s worth and more expensive for a variety of reasons, something that’s more of a legacy holdout than anything else.

Don’t really think any of those are “rule of thumb” in my mind, as the choice between single chassis stereo vs monoblock vs bridged monoblock, and biamping is very situational and really depends on a lot of aspects to where it’s really hard to give any simple answer of what’s worthwhile or not. Once you bring value into things it gets really hard to say what’s actually worth doing or not.

3

Thank you @M0N
That was EXACTLY what I was fishing for!

So generally speaking - if I have a given budget specifically for amplification, I would be best off spending that budge on a single stereo amp rather than two monoblocks which cost half that budget each?

4

Very useful in the pro audio world as it allows each driver to have its own independent channel of DSP.

It could be useful in the hifi world also for the same reasons, if digital processing wasn’t the devil :wink:

1 Like
5

Depends on the budget, the actual amps you’re looking at, and the speakers and rest of the chain

See I was going to mention that, but it’s not really relevant in most hifi situations since you really don’t need that extra power, and most hifi speakers don’t have external and/or active crossovers. Not to say there aren’t good designs like that in the high end, but those tend to be integrated into the speakers themselves at that point as active monitors more often than not or are electronics designed to specifically pair with that set of speakers so the “what amps” question isn’t even one that needs to be asked. This is assuming premade though, this will come into play with more diy designs. But yes common in pro audio

All depends on the tradeoffs, there’s good digital processing and bad. Sometimes depending on the system can be more improvement than not, sometimes more detrimental than improvement even with nice digital processing options

6

The “rule of thumb” that i usually find and that most often comes is the 3db rule.
3 dB increase|sound energy is doubled
3 dB decrease|sound energy is halved
or double the power or change box closed vs venter or larger driver etc.

If you would have 100db with 500wrms.
To double the sound energy. You would have 103 db and with 1000wrms.

The price doubling and rules of thumbs is something not i have noticed.

7

technically that isn’t a rule of thumb imo, as a rule of thumb in definition is based on practical experience rather than hard/strictly defined theory/science. That’s also only with actual energy and not perceived loudness, as that’s going to be more ~10db is a double in perceived loudness which will vary from person to person and other aspects, so perceived loudness is going to be more rule of thumb worthy than actual loudness in my mind as that’s more subjective/in practice. But guess there’s not anything saying that hard science/theory can’t be a rule of thumb, it’s just very typically not how that phrase is used and what’s attached to it, that’s more just a strict rule, rather than a rule of thumb for how I think about the phrase lol

1 Like