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Distortion figures on nearfield monitor speakers
Old 22nd May 2019
  #1
Gear Head
 

Distortion figures on nearfield monitor speakers

Just wondering, how come so many (particularly budget and mid-range) manufacturers don't display their speakers distortion (THD) figures?

Was very interested in the Focal Alpha 65 with their 40-21000hz range but can't find any distortion specs. Makes me wonder at what distortion are they getting that low-end extension out of a 6.5" woofer?
Old 22nd May 2019
  #2
Lives for gear
 
O.F.F.'s Avatar
 

Practically no speaker or driver manufacturer publishes THD figures.

One of the reasons being is that people are used to THD numbers from amps, preamps etc.
Speakers produce frequency dependent THD orders of magnitude higher than those. A single number won't work so a curve is needed which is complicating things a fair bit (for the average consumer) and while amps stay below 0.1% unless clipping, speakers easily reach well over 10% THD in the bass region.


When it comes to monitors Neumann is one that springs to mind who does publish distortion figures, ME Geithain might be another if I remember right.
Old 22nd May 2019
  #3
Gear Guru
 
John Willett's Avatar
 

Quote:
Originally Posted by O.F.F. View Post
ME Geithain might be another if I remember right.
Yes

Quote:
Total harmonic distortion measured at 96dB / r=1m (3.3ft) from 100Hz ... 10kHz
Old 22nd May 2019
  #4
Gear Head
 

Ok. Tho JBL & Kali Audio have published figures for their 'budget' models so if, for example, Focal's budget range is clearly better surely it would be in their interest to publicise it?
Old 4 weeks ago
  #5
Gear Head
 

Focal Alpha 65 distortion specs

Quote:
Originally Posted by O.F.F. View Post
Practically no speaker or driver manufacturer publishes THD figures.

One of the reasons being is that people are used to THD numbers from amps, preamps etc.
Speakers produce frequency dependent THD orders of magnitude higher than those. A single number won't work so a curve is needed which is complicating things a fair bit (for the average consumer) and while amps stay below 0.1% unless clipping, speakers easily reach well over 10% THD in the bass region.
Hi again, I found a German literature that had some measurements for the Focal Alpha 65. It had the following:

Max. Nutzlautstärke:
100.2 dB (3% THD 100 Hz - 10 kHz)

Bass suitability:
101 dB (10% THD 50 - 100 Hz)

Any good?

Couldn't find a translation for Nutzlautstärke but maybe means SPL?
Old 4 weeks ago
  #6
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O.F.F.'s Avatar
 

Max. Nutzlautstärke means maximum usable volume
Old 4 weeks ago
  #7
Gear Head
 

Follow up / Focal Alpha 65 or Kali Audio LP-6?

Quote:
Originally Posted by O.F.F. View Post
Max. Nutzlautstärke means maximum usable volume
Thanks, your German skills are better than mine obviously!


I'm considering either Focal Alpha 65's or Kali Audio LP-6 for a 14x10ft room which I will be treating properly. The Kali LP-6 distortion figures are as follows:

Max SPL: 112 dB
System THD (94 dB @ 1 M): <3% 80 Hz - 1.7 kHz, <2% above 1.7 kHz

Compared to the Focal's specs given above this implies to my limited knowledge that the Alpha's are obviously more powerful but possibly have more distortion in the upper frequencies (above 10kHz). Maybe I will go for the Kali as they're cheaper and seem really flat on the FR too...

Last edited by Denta; 4 weeks ago at 08:31 PM.. Reason: Changed title
Old 4 weeks ago
  #8
Lives for gear
 

Isn't it more valuable to see a waterfall and or a graph with 2nd/3rd order distortion rather than the total?
Old 4 weeks ago
  #9
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O.F.F.'s Avatar
 

Pick the ones that work better in your room.


OK, true but it is the weasly way out.
The truth is that I have no interest in putting my name on a financial decision you are making regarding two monitors I am not familiar with.


That said the only actual info I can draw from those numbers and assuming they are actually true and derived in a similar environment and methods is that at 3% THD from 100-1.7k the Kali produces 94dBspl while the Focal produces 100.2dBspl.

Everything else is conjecture. Make of it what you will but the Kali's THD at 100dB might or might not look dramatically different. The Focals might or might not be better at 94. Lots of unknowns...
Old 4 weeks ago
  #10
Gear Head
 

Is lots of unknowns I agree. Going to go for Kali's - they're cheaper and look slightly flatter on FR, albeit not reaching quite as low. Should be good for a smallish (12sq metre) room...
Old 4 weeks ago
  #11
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Fay Smearing's Avatar
 

The less hard you drive them the less the distortion will be, both in terms of cone/driver excursion and amplifier output.

At one meter or so, nearfield, working at a sensible 75-85 db with monitors that can hit 100 or more, you'd be at lower distortion numbers than if they're being cranked to near their max spl.

Do the math on your listening distance and use something that delivers the level you need with plenty in reserve.
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