Refining the Old Girl

[toddalin]

The other day I posted the spectrum for the Ethyl Mermans and it was easy to see why they do female voices so well.

But now they gots more balls. I revised the crossovers to push more energy into the depression between ~250 - 1.6kHz and fatten up the very bottom end of the 2241. Also smoothed the dip at 10kHz a bit.

Again, these are from where I sit on the couch with no subs, eq, digital processing, etc.

Yesterday:


Today:

[Ian Mackenzie]

Hi Todd,

How did you EQ the 2241 bottom end?

Is that scale on your analyser 10 dB per division?

Can l suggest you try our REW with the Minidsp USB calibrated mic. REW is freeware and can run on Windows or Mac.

REW will significantly improve on your current analysers measurements and enable other types of measurements such as distortion, impulse response and power response measurements. Used together these other measurements provide a more meaningful indicators of how the loudspeaker is performing against your objectives. It should be pointed out that a sole on axis response measurement should not be the sole performance criteria for assessing the subjective performance of a loudspeaker.

If you read up on Floyd’s papers and presentations you will see there is a more scientific approach to assessment of loudspeakers.

[toddalin]

Hi Todd,

How did you EQ the 2241 bottom end?

Is that scale on your analyser 10 dB per division?

Can l suggest you try our REW with the Minidsp USB calibrated mic. REW is freeware and can run on Windows or Mac.

REW will significantly improve on your current analysers measurements and enable other types of measurements such as distortion, impulse response and power response measurements. Used together these other measurements provide a more meaningful indicators of how the loudspeaker is performing against your objectives. It should be pointed out that a sole on axis response measurement should not be the sole performance criteria for assessing the subjective performance of a loudspeaker.

If you read up on Floyd’s papers and presentations you will see there is a more scientific approach to assessment of loudspeakers.

~4mH/30mfd gave the best blend to the 2251J. Recognize I only work with what I have on hand, so values could certainly be better optimized.

It's 5 dB per division so we are at ~-70DB +-~5 dB down to ~32 Hz. The full scale is 30 dB, which is what I saw being used with Rob's software. Again, +-5 dB is not bad measured in the room on the couch with no correction of any kind.

[toddalin]

Actually, when you consider what I was working with...,

2241H spectrum (JBL service manual):


2251J measurement:


Heil AMT:


Create a new "acoustic lens" and apply appropriate rear isolation for the Heil, blend it all together with Audyn Q4 caps and 16 gauge air core chokes, carefully, and voila: