JBL 4346 DYI with 2123H

With with the studio-six app, this little guy is still no earthworks mic, but a lot less hassle then a mic/stand/cables/audio I-O interface/computer :)

http://www.parts-express.com/dayton-...droid--390-810

Thanks Grumpy

Agree we need to validate the measurements if possible.

While we are waiting on details of the mic location it lools like the response from 1200 Hz up is uniformly shelved some 6 db approximately.

I am theorising that is a level mis match on the HF and UHF filters or there is a lot of bleed from the woofer /mid cone as this is pink noise and not a solo tracking single frequency measurement.

Lets ee what our friend comes back with.

Never thought my issues will attract so much help. Thank you guys you are really something...


i used RTA app from onyx. i have an Iphone 5s. i took the measurements as follows

the full drivers at about 90 cm in front of the speaker

each individual driver was measured on axis at about 30 cm.

if you give me indications i can repeat the measurements with your parameters.

Hi

Was the full drivers measurement on axis with a particular driver?

no, somewhwre between the mid and the woofer

Okay,

Ideally (if practical) the measurements should be centred with the baffle at a height level with the bottom edge of the horn.

You might need to put the iPhone on a chair or a camera tripod.

Alternatively turn the enclosure upside down and raise the iPhone off the floor until it's at the right position.

The reason is the horn and slot have quite narrow vertical coverage.

I would try a do a full driver measurement at 2 metres distance.

This will help the wave fronts of the individual drivers merge in manner as heard by the listener.

You might get some interference from the room at low frequencies but we are interested in the response above 700 hertz.

2m in front of the baffle full on lpads between hf and uhf below the horn

Okay looks a lot more like it

What is the distinction of the two curves ?

Those curves are quite typical of this system.

The system response is not a magazine response curve.

My suggestion is to get a pair of the 2308 on EBay , they are about 120.00 new from Kenji.

The lense will modify the subjective and objective performance.

I recommend you considered obtaining the Dayton mic in Grumpys post.

This will provide more meaningful measurement as you can calibrate the mic.

Thanks

Evidence the data sheet on the Beyma slot

https://www.hifisound.de/out/media/p...kdVQ%3D%3D.pdf

Quote:

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Originally Posted by Ian Mackenzie

Evidence the data sheet on the Beyma slot

https://www.hifisound.de/out/media/p...kdVQ%3D%3D.pdf

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Hi,

1.
Using 2308 lenses would reduce higher FR-response due to the spreading off-axis response especially over 4kHz, that would reduce the response , as I have remembered about 3~4 dB.

2. Due to the geometrical differences between VHF and UHF drivers, a kind of comb-filter effect would be evident, especially round 8kHz~12kHz when passive network without time delay compensation is applied. Even with the time compensated electronic network, due to the drivers baffle mounting a kind of the same effect can be get, but I believe that all of that would be hard to be recognized by the listener.

3.
I think a kind of adequate measuring equipment has to be used not as mob-phone (garbage-in->garbage-out).

4.
I think that firstly drivers sensitivity has to be adjusted, and after that I would not expect any great problem at all as any of the used driver is of high quality and very linear, may be the best of any.
5.
I would prefer 2441/45/46/50 & 2311 instead of 242x & 2307, as such combination seems to me more natural sound in the lower VHF FR-spectrum (may be due to the larger diaphragm surface)

regards
ivica

Hi Ivica

Thank you for your insights.

Those Beyma slots are cute.

Did you ever get around to using them?

Hi guys. Thanks again for all your input. i will get a Dayton mic myself and make some measurements. However it seems that something eludes me. It is the sound that is not that clear. As it is a fundamental issue like for example the cables or the drivers are veiling the sound. I was under the impression that the sound of these
monitors should be clearer. Is it something that I miss? should i change the
diaphragms of the 2425's should i change theninternal cables? or this is the end sound of the apeakers and i should get along with that?

the thig is that i heard the spekers the guys at krs were rebuilding abd they sounded very crisp and clear. Not mine.... Please help

Thank you for your input.

Dear ivica,

Please see my comments inline.

thank you for your answers

Bogdan

Quote:

---

Originally Posted by ivica

Hi,

1.
Using 2308 lenses would reduce higher FR-response due to the spreading off-axis response especially over 4kHz, that would reduce the response , as I have remembered about 3~4 dB.

so should i purchase the 2308 lenses or not. Would that improve o. the sound clarity?

2. Due to the geometrical differences between VHF and UHF drivers, a kind of comb-filter effect would be evident, especially round 8kHz~12kHz when passive network without time delay compensation is applied. Even with the time compensated electronic network, due to the drivers baffle mounting a kind of the same effect can be get, but I believe that all of that would be hard to be recognized by the listener.

is there anythig here that may be improved?

3.
I think a kind of adequate measuring equipment has to be used not as mob-phone (garbage-in->garbage-out).
i will purchase a Dayton calibrated mic.


4.
I think that firstly drivers sensitivity has to be adjusted, and after that I would not expect any great problem at all as any of the used driver is of high quality and very linear, may be the best of any.


How can I adjust
the
drivers sensitivity?
5.
I would prefer 2441/45/46/50 & 2311 instead of 242x & 2307, as such combination seems to me more natural sound in the lower VHF FR-spectrum (may be due to the larger diaphragm surface)


Is there a possibility to improve these 2425's ?
regards
ivica

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