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Multi-Way Conventional loudspeakers with crossovers

Beyond the Ariel
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Old 5th November 2008, 11:07 AM   #4691
mige0 is offline mige0  Austria
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Quote:
Originally posted by Kolbrek



Seems like I have to release my BEM SW...
....

I will rather spend that time working on the SW, and eventually make it available to the public later. I hope you understand.

Bjørn

Soon as you take preorders, Bjørn - please drop me a PM.




-------------


Have put my work and some personal findings about BDMD (and the extra ordinary event of this very day ) into a paper available through the link below in order to give a more compact picture about the topic and some of the conclusions having evolved from this thread .


Michael
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Old 5th November 2008, 12:54 PM   #4692
Kolbrek is offline Kolbrek  Norway
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Quote:
Originally posted by mige0

Soon as you take preorders, Bjørn - please drop me a PM.
Don't hold your breath

Bjørn
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Old 5th November 2008, 01:51 PM   #4693
gedlee is offline gedlee  United States
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Default Re: OSWG BEM simulation

Quote:
Originally posted by Kolbrek
Hi Earl, all,
Attached is the frequency response with driver at different angles. Does this resemble your measurements, Earl?

It would in any case be interesting to see a frequency response measurement of your waveguide with driver, without the crossover. Also the electrical impedance would be interesting to see.

Bjørn
Bjorn

Thank you very much for this. From your data I am assuming that the mouth of this waveguide would be 10", my smallest. I have data for this device and I will post it as a comparison, but I should also say that this waveguide is the worst of the bunch being just too small. The 12" and 15" devices are much better. But at any rate I'd have to say that you have achieved all of the pertinent features that I find. First the constant directivity, and the -6 dB / oct HF loss is typical. The lowest resonance peak is "tamed" by the HP filter and the next one, which I don't typically see this strong (but I use foam remember) needs a second tank circuit to control. The hole on axis is now quit accurate.

I'll dig up my data and post it.
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Old 5th November 2008, 02:37 PM   #4694
Paul W is offline Paul W  United States
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Quote:
I will rather spend that time working on the SW, and eventually make it available to the public later. I hope you understand.
No problem at all...thanks for considering the request.
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Old 5th November 2008, 02:54 PM   #4695
gedlee is offline gedlee  United States
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Here is my data for the Nathan 10" waveguide with a DE250. We mostly agree, but the bump at LFs is not in your data. This is likely due to the throat and the gap in front of the diaphragm not being correct.

Click the image to open in full size.

There is clearly more damping of the resonanaces in my device, this could be the foam, but, in general, I don't find the foam having that much of an effect. Perhaps the driver has more Bl than you have used. I'll dig up an impedance curve and post it too.
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Old 5th November 2008, 03:03 PM   #4696
soongsc is offline soongsc  Taiwan
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I somehow recall it rolling off at 16KHz or so, this one seems to roll off a lot earlier.
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Old 5th November 2008, 03:35 PM   #4697
gedlee is offline gedlee  United States
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The sample rate here was only 32 kHz so what you are seeing is the anti-aliasing filter. I never look at data above 10 kHz so I don't even notice these sorts of things.
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Old 5th November 2008, 09:45 PM   #4698
Nevod is offline Nevod  Russian Federation
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Sorry for interrupting again.
Well, maybe the tweeter is already chosen - I haven't read the whole (very interesting indeed!) thread, but still:

Has anyone read something about new Alcons Audio pro-ribbons? The RBN1801 and smaller RBN601, particularly?

Some states on RBN1801:
108dB/m sensitivity
210W continious power handling / 3kW peak handling
1kHz - to over 20 kHz responce.

RBN601 is similar, but smaller and less powerful. But even that is very enough. If only we could have 130dB SPL in the whole band..
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Old 6th November 2008, 01:27 AM   #4699
tech.knockout is offline tech.knockout  Australia
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Default Re: Listmania Part II

Quote:
Originally posted by CLS 10NDA610 is fully equipped: strong motor, light cone, extremely low inductance. So powerful in such a wide range!
It has a rising response with little midbass; which can mean its range is actually not very wide. This is unless you use a wide baffle which can make it usable from around 300hz. Although the cone at first impressions from the graph is good and minimal breakup. Its 10 inch size is very deceptive. Take note its Xmax by the simplest definition is 0; the manufacturer uses a diff formula.

Although to be fair the manufacturer measurements are taken in full space in a 30L box. This is in comparison to other manufacturer graphs some of which are taken with infinite baffle.
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Old 6th November 2008, 01:48 AM   #4700
CLS is offline CLS  Taiwan
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Thanks for attention. I've noticed its rising response, too.

And also, I'm still confused by such "evaluation". The results are quite different from what I've experienced (subjectively). So it'd probably be something wrong (or lackings) with the table

By the way, 250Hz was picked because of many smaller drivers are affected by their low end resonant peak of impedance at slightly lower frenquency than this. Say, some drivers actually ride on the half way towards their peak at around 150Hz. So I can not take that frequency (or lower) to calculate their actual impedance by the Re and Le. Around and below this region, driver's behavior is dominated by other things instead of inductance.

So in the end, this seems all in vain. Or I need many more other factors to make it right.
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