It's the pipe organ effect
Careful placement and minimising turbulence around the openings will minimise this.
I have seen simulation where 5mm change in placement can have a significant impact.
It's the pipe organ effect
Careful placement and minimising turbulence around the openings will minimise this.
I have seen simulation where 5mm change in placement can have a significant impact.
Hi Ian,
Do recall if there was a particular nearby "feature" that was the subject of the simulation?
e.g., cabinet edge, floor, driver, adjacent port, adjacent "wall" (close enough approaching slot loading)
whether part of the cabinet system or not,... Just curious, as "significant" can mean functional (audible)
or/and measurable. I can imagine this port placement sensitivity being quite system specific.
hi
following this thread for a while now and have finally decided to take the plunge.
i will receive a pair of jbl D2430k drivers and am looking for a pair of M2 horn lenses and adapters.
could anybody point me to where i can get them aside from speakerex ?
any help is appreciated.
malcolm
edit: i just realized that i should have probably posted this in the m2 diy thread .
Nearfield measurements of my clones with original EQ settings. DSP is Hypex DLCP
No smoothing. Dont like that peak at 254hz...
We had some discussions earlier regarding the acoustic crossover in M2. Electrical, 2216nd is crossed over with 36dB/oct LR. I added a target curve showing 8th order LR (48dB/oct) in REW, and it seems to match pretty good...
Without EQ at the "trouble area"
Your dips/peaks around 250hz look similar to Scott's ones.
The peak dissapears in far field measurement, but the dip is still there. Overall response looks good, but indoor measurements are hard to rely on.
According to all my measurements the target is a LR 36dB/oct a bit under 800Hz, both for phase and amplitude.Originally Posted by johanwholst
Each driver measured on axis, ~1m distance.
That is a pretty well-matched LR 36dB/oct at 750Hz.
No doubt! Thanks for the confirmation...
Hi Pos,
I noticed that every time I take a spatial average of my M2s in a room (6 positions, 1m square, ~3m measurement distance) I find a peak centered at around 8.1 kHz.
A few people on another forum have suggested that the openDRC-AN with rephase may not behave 100% predictably. Do you think there could be something strange going on with the high end?
Hi Synthetic
There can be minor differences up top, partially because of the different DACs and amplifiers, but also due to the IIR implementation in the Crown/BSS (Qs are never fully correct up high with biquads).
But I think that 8kHz thing is as least partially intended: http://www.audioheritage.org/vbullet...ht=#post391305
The strange thing to me, that I also measure and see in most "real world" Crown-powered M2 measurements, is the 6.5kHz dip...
That would be great if someone with the BSS unit could measure the outputs of the processor with the M2 preset engaged.
Here is a set of measurements of the M2 in different medium to large rooms, from FLoyd Tool's presentation (go to 1:11:40), that clearly show the same phenomenon:
What I see is a gradual "sag" from 3 - 8K. 3 and 8K are actually where they should be. As you indicate above, there's a lot going on with all that gear, data acquisition. A "witch hunt."
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