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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
15,878 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
901 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".

herman
2,216 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.

 

I’ll try one more time and then leave you to it. I don’t care how much your room is adding to it, it is impossible you are getting the same level at 20 Hz that you are in the midband with a 6.5 inch speaker.. impossible.... your measurements are incorrect.

something is wrong with your measurements at the top end too when you turn up the midband by 10dB (red to yellow) but at 20KHz it goes up 20dB

if you play a 20 Hz tone do you hear it?

erik_squires OP
15,878 posts
 

@herman 

What can I say, I have measured using OmniMic and Room EQ Wizard with two different calibrated mics.  The two mics were in agreement except for the range from 20Hz to 30 Hz where UMIK was 3-5 dB down @ 20Hz  depending on exactly how I placed the mics. It then merged with the measurements with OmniMic at 30.

I even tried using two different DAC's, one direct and one via Roon.  This may not be lab quality work but I'm satisfied it's in the ballpark.

hesson11
237 posts
 

This discussion reminds me of a 1987 Stereophile article by Martin Colloms. Basically, it talks about how to optimize bass response through room positioning. Nothing groundbreaking, but a good reminder:

https://www.stereophile.com/content/who-stole-bass-no-one-stole-bass-page-4

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