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Guess How Big My Speakers Are

If you read any of my threads on here or looked at my virtual system you probably already know the answer to this question, but for those who have not, try this as a thought exercise. Given this plot alone how big a speaker do you think this is?

Frequency response plot showint extension to 20 Hz

 

Hints:

  • 2’ from sides, 1.5’ from rear
  • Ported
  • Not horns
  • No EQ applied. This is the natural in room response using short sine sweeps.
  • For a living room this is a well treated room with GIK soffit traps, bass traps and diffusion panels strategically placed.

I’ll reveal my answer if we get 5 guesses or more. :)

erik_squires
erik_squires OP
16,037 posts
 

@herman but it is, and I’ve measured it. It’s not "real." It’s not the capability of the speaker so much as the resonance of the room.

Rooms can add 20 dB or more in a node, so this is totally possible. However, it is very much range limited. :)

 

From my new blog entry, you can see that compression eventually must set in...

 

Here you can see the output at 60, 70 and 80 dB is fine, only when we get to 90 dB is the output compressed.

erik_squires OP
16,037 posts
 

@herman 

I did retest using Room EQ Wizard and OmniMic.  REW measures about 5 dB lower at 20 Hz than OmniMIc.  It also shows a weird clipping at the top octaves.

While I agree 100% that you can't get loud at 20 Hz with small drivers (this is pure physics) I hope you see that my argument that rooms are complicated and we can't assume we know what's going on without measurement is worthwhile. :)

james633
1,005 posts
 

While deep the output is only 75db in the graph so could be anything. Large speakers are needed for full range at high output. Small active speakers go super deep, just not loud without compressing. 

erik_squires OP
16,037 posts
 

@james633  - Absolutely right.  No way we are getting live level performances out of these.

One thing this shows too though is that if we wanted to use a sub we absolutely have to high pass these speakers or the combination would be a hot mess.

ejr1953
912 posts
 

Very interesting discussion, Erik thank you for stimulating that.

On the subject of sub woofers, I had my pair turned "off" while the amplifier in one of them was being repaired and I really missed the "visceral" experience they add to the musical experience.  When the repaired amp was reinstalled, I used the DSP engine tuning and REW/miniDSP microphone setup to "tune" the subs to the room and the full-range speakers.  You've peaked my interest in seeing what REW/miniDSP reports with the sub woofers turned "off".

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