Fun with speaker placement :-)

[manisandher]

I thought I'd start a new topic to follow on from this:

... I think the sound is pretty good... but still not quite 'there'. If I adjust the speakers so that voices sound palpable and real, the LF (below 60Hz, say) seems slightly lacking. If I adjust them so that this LF is more pronounced, the mid-lows/upper-bass seem too prominent - vocals become unrealistically husky.

I decided to take a few measurements. The obvious tool would be REW, which I've used in the past. But I wanted to use the system exactly as it is (XX -> NOS1 -> BD amps -> Anima speakers), and not mess around switching gear. So, I decided to simply play a pink noise signal and capture the speaker output at the listening position with a measurement mic. The charts below show the following:

1. The pink noise signal, with its -3dB/octave slope on the FFT

- exactly as expected
- in an ideal world, it'd be great to be within a few dB of this curve

2. The captured signal, with the original speaker position (placed right in the corner).

- ~-8dB/octave roll-off below 60Hz
- 'hump' between 100-200Hz
- lack of HF above 10kHz
- matches my comment, "If I adjust them so that this LF is more pronounced, the mid-lows/upper-bass seem too prominent - vocals become unrealistically husky."

3. Hypothetically increasing the mid and high by 4dB (I didn't actually do this)

- would solve the 'hump' issue
- would exacerbate lack of LF
- lack of HF would remain
- matches my comment, "If I adjust the speakers so that voices sound palpable and real, the LF (below 60Hz, say) seems slightly lacking."

4. What I actually did: moved the speakers away from corner, and reduced the mid/high level. (This no doubt reduces the overall sensitivity of the speakers, and probably necessitates the use of a reasonably powerful amp.)

- ~-8dB/octave roll-off below 60Hz remains
- 'hump' between 100-200Hz now elimated
- HF now drops away above 15kHz

The sound is now substantially better balanced with the new speaker placement. However, there's still the unavoidable roll-off below 60Hz. (Just to put this is context though - with the Orelos, I had a dip of 25dB at 50Hz in this same room!) I'm going to see how I go before I start thinking about what to do (if anything).

One thing that I already know though is that I'd prefer the sound to be a bit more... what's the word?... hmm... how can I describe it?... ah, I know... lush!

Mani.

[briefremarks]

Mani,

I was just about to post something asking about experiences with speaker placement, room treatments, etc.  I know that VJ had posted earlier about the dramatic differences after he re-arranged Orelos and treated his room.

I've started to get used to the astonishing dynamics and clarity of the Orelos, and with the break-in now underway want to take some measurements and see how frequencies look with variations in placement.

The main variable for me is the distance from the "front wall".  I've tried everything from 10" to 24".  Further out sounds more spacious.  Have not tried any of the FM switches yet.

Of course, I'm trying to find a balance between optimum sound and everyday living!

Ramesh

[PeterSt]

Hi Mani,

Very nice work of sharing (or asking ).

I think if you toe in or out a little bit and let remain the measuring microphone at the listening position, the dip beyond 15KHz will disappear.

I already noticed your direct beaming (speakers face dead to you) which I think is not the best way for horns of this kind.
You may think it will work out better for the highs, but it is actually the other way around. Anyway, easy to try ...

Peter

[manisandher]

I was just about to post something asking about experiences with speaker placement, room treatments, etc.

Hi Ramesh, glad to hear things seem to be going well with the Orelos.

Of course, having the DSP in the LF of the Orelos means you have so much more flexibility than I have with my current speakers. I used the DSP in the Orelos to overcome the dip I was experiencing in the LF (see attached).

Pic 1 - Response from 30Hz to 70Hz with the mic placed just in front of the speaker vs. at the listening position. There was a 25dB dip between 65-35Hz at the listening position.

Pic 2 - Response at the listening position with DSP. Very similar to that with mic placed in front of speaker.

But I have to say that correcting for such a large dip with DSP came at a cost, and I reverted back to the original settings after a while.

Mani.

[manisandher]

I think if you toe in or out a little bit and let remain the measuring microphone at the listening position, the dip beyond 15KHz will disappear.

Thanks Peter, I'll give it a go.

Mani.