2. tech-talk
  3. 194542-91377

Wasted amp power to limited range speakers...how degrading is it to SQ?

Per title, basically trying to understand the electrical science more with power amplification and transducers in passive speakers when it comes to low frequencies the speakers may struggle to produce. to start with, here’s my amp/speaker chain right now:

SF Sonetto 1
Arcam SA20
SVS Micro3000 sub

NOTE: I probably am restating the same question in multiple ways, or maybe asking questions that are too different to be tied together well…i simply don't understand electrical physics for this stuff well at all.

I use preout on my arcam to the sub and lowpass to set sub performance well...but I’m more concerned with the power chain to the sonetto’s. Power to produce all frequencies is being sent to the sonettos…including frequencies they have no hope to reproduce. Given lower octave frequencies are most difficult to properly power for an amplifier…isn’t it massively detrimental to it’s power delivery/speed elsewhere in the midbass+ frequency ranges? 

Isn’t the amp doing its hardest work for nothing? I understand that the arcam is neither AVR nor a very high end piece but am I misunderstanding power delivery to think this is a huge issue with this amplifier and others that don’t have adjustable high pass filters for stereo speakers? if it is a detrimental effect…what would that look like? Leaner delivery? more vol cranking to get going?

When i’ve read reviews in the past of amps that do  (say, parasound hint 6 or something), its discussed as a nice bonus feature…when my intuition (though incredibly novice here) screams that this is much much more detrimental than ’oh well cant have everything’, more like a significant kneecap in its speed and control? 

if it's not an issue, is it because theres some element in the power amplification stage that routes power appropriately for the given speaker? is it up to the speaker to handle that (even if passive)? Wouldn't think the latter for passives but maybe the power stage part? im lost lol.

What am I missing? Is it not a big deal? Is there some factor to the sonetto woofer not actively moving to produce lowest frequencies that makes it not draw much power to begin with for those? what about the lowest frequencies it CAN ’produce’ (though not in the best manner)...say 40-60hz region etc.

I tried looking for threads but honestly didn’t quite know how to search this and didnt find quite the results i was looking for.

TLDR: 
- When a speaker has limited frequency range, how are amplifier stages handling energy ’needed’ to produce frequencies outside of the speakers ability?
- is the speaker simply not drawing energy for those from the poweramp stage? 
- Is there NOT a tremendous waste of energy by speaker and/or amp to worry about?

zander024
kennyc
1,888 posts
 

+1 you’re overthinking this

Amps are rarely used to their full power.  Increased headroom often leads to better sonics running at lower wattage.  Only class A is considered highly inefficient as it runs full power and gives off lots of heat.  Understanding a speaker’s impedance and phase angle graph helps to understand how easy/difficult the speaker is to drive including electrical current needs.  Understand a speakers frequency to amplitude graph helps to understand how neutral a speaker is and it’s frequency extremes.

erik_squires
16,728 posts
 

Hi OP:

So without a high pass filter before the main amp, the main amp produced the same voltage no matter what the sub does, and the speakers attempt the bass frequencies as best they can.

From a technical perspective, adding a high pass filter before an amp can really reduce wasted power... but it's rare that it even matters outside of professional applications.  What really matters is reducing the distortion of the midwoofer.

It is often highly beneficial to high pass the main speakers and, if ported, to seal the ports.  Use as high of a cut off frequency as you can (80 to 120Hz), not the lowest. The real sonic benefits of a sub + satellites comes when you can reduce the distortion of the mid-woofer. 

Best,

 

Erik

audio_guy_uofw
64 posts
 

This is typically not really an amplifier issue, unless you are pushing the output capabilities of the amp. It IS a speaker issue, however, as the LF can heat up the voice coil even if the speaker can't reproduce them, and they can cause significant cone excursion. Plus depending on the design the LF can modulate the higher frequencies causing distortion. So for the speaker it is indeed better to limit the input to frequencies it can reproduce.

More to discover