Eucy.
This product is the same price as the behringer, no idea how good it is.
I have used the beringer microphone for many years ,with no problems.
I have just bought a new one as the old one has been rather accidentally bashed around by me on many occasions.
It still works but I thought it was time to replace it,it's so cheap, and stereo microphones could be handy at some time if I bought the dac ?
Steve.
This product is the same price as the behringer, no idea how good it is.
I have used the beringer microphone for many years ,with no problems.
I have just bought a new one as the old one has been rather accidentally bashed around by me on many occasions.
It still works but I thought it was time to replace it,it's so cheap, and stereo microphones could be handy at some time if I bought the dac ?
Steve.
https://www.gear4music.com/
Oops forgot to post it.
Steve.
Sorry this link just takes you to the site.
Look for the subzero m100 mic.
£30.
Oops forgot to post it.
Steve.
Sorry this link just takes you to the site.
Look for the subzero m100 mic.
£30.
Hi Christian
Yep. It's electret... Need a power injector..48v to 5v will allow use of the phantom power supply, or use a separate battery powered injector
I could use a buck converter but not sure how noisy they are
RODE make an XLR to 3.5mm adaptor with a power converter 48v to 5v -> they're about $30-$40
I knew I'd be a rabbit hole..🤫
Eucy
Yep. It's electret... Need a power injector..48v to 5v will allow use of the phantom power supply, or use a separate battery powered injector
I could use a buck converter but not sure how noisy they are
RODE make an XLR to 3.5mm adaptor with a power converter 48v to 5v -> they're about $30-$40
I knew I'd be a rabbit hole..🤫
Eucy
This and the absence of calibration files is what put me off the 8000 Steve
https://www.cross-spectrum.com/weblog/2009/07/
Eucy
Hello Steve,
Very good advice. 2 interesting figures in the specifications : sensitivity at -34dB, noise 18dB. I haven't found those figures for the Behringer ECM8000 (-37dB sensitivity in a wiki page). My preference would go to the product with the most detailed specification.
Christian
Please forget any switching supply!!!!!!!!!!!! If needed a simple 9V battery would be more suitable.
You can have a look to this Rod Elliot page about electret
I am not familiar with the XLR mic input with 48V supply. Need to learn...
I think I have some where the german article... to be check being back to our main location... Seems there are some variation in the ECM8000 production...
About 48V phantom... it is definitively not suitable for electret without additional components. See the schematic below (source)
I think there are smart schematics using few components (transistors, diode...) to connect an electret to an XLR input keeping the 48V supply and the differential transmission. To be checked
I'm using this as a cheap and convenient solution:
https://www.amazon.se/Omnitronic-Mikrofon-2USB-Kondensor-Messm/dp/B078Y59NPT/ref=sr_1_5?crid=14AK6GM4BX9KQ&keywords=mätmikrofon&qid=1660915913&sprefix=mätmikrofon,aps,85&sr=8-5
If it is only for measuring with a computer on the cheap it is probably a decent option, but not sure yet how good it is really. I do get some interference showing up when using it on my laptop, but that can happen with USB audio interfaces of all sorts sometimes, so not certain how much better I would have faired with a separate soundcard and mic.
https://www.amazon.se/Omnitronic-Mikrofon-2USB-Kondensor-Messm/dp/B078Y59NPT/ref=sr_1_5?crid=14AK6GM4BX9KQ&keywords=mätmikrofon&qid=1660915913&sprefix=mätmikrofon,aps,85&sr=8-5
If it is only for measuring with a computer on the cheap it is probably a decent option, but not sure yet how good it is really. I do get some interference showing up when using it on my laptop, but that can happen with USB audio interfaces of all sorts sometimes, so not certain how much better I would have faired with a separate soundcard and mic.
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I've been using the MiniDSP USB measurement mic for several years with no issues. It has a calibration file and integrates easily with REW.
https://www.minidsp.com/products/acoustic-measurement/umik-1
https://www.minidsp.com/products/acoustic-measurement/umik-1
Hello Eric
The goal of the delay measurements I did was to try to see the velocity of the waves in the panel. The files are in my hard drive... but so many topics!
I had the possibility to make some outdoor measurements. You will find below the spectrograms.
1/ EPS 20mm 60x80cm PVA coated on both side
2/ XPS 20mm 60x60cm not coated. This piece is highly ringing (donnng!) when hitting it.
They were measured from the same locations (at 1m)
I have added the spectrogram of my plywood panel measured in the same garden but last year also in August.
Well... what to say? not easy...
- Horizontal lines are events occurring at the same time for all the frequencies. So reflections?
- Vertical lines are phenomena at a particular frequency. Typically a mode?
- The EPS seems having lower levels earlier than the 2 others. So a more adapted damping?
- The XPS (I wouldn't listen music from it) and the plywood (I like the music from it) show frequencies with a decreasing level that increases again after a moment (see yellow islands). Is it what your are looking for???? Is it a summation of a mode and a reflection. The phenomena is not so visible with the EPS. The condition of measurement were not really good, the afternoon was a bit too windy.
I hope it will give you some inputs and at least examples of the spectrogram.
Let me know if the assumption of the summation of a delayed energy in the panel due to a mode and a room reflection makes sens to you. I have some indoor measurements of the same panels showing this kind of island but with even higher levels.
I have also pictures of the panels in the garden!
What is missing in REW is the possibility to make a slice at a given frequency. The slice at a given time is not precise enough (no possibility to enter the time, ie 0s). I am thinking to write a Python script doing that. An other interesting feature might be also to show a contour a -10dB/peak for example for each frequency to appreciate the damping.
As you can detect the phenomena by listening some music, a experiment might be to listen the same panel, same music in an other location or with some mean (curtains?) to change the reflections and listen is the echo is still here.
By the way, those experiments lead me to a better understanding (I hope) about the high frequencies performance... I'll share it in an other post.
Christian
EPS20mm
XPS20mm
Plywood 3mm
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High frequency performance
With the standard loudspeaker, I was used to make simulations of filter based on the electrical model of the speaker. For DML, several papers propose a simplified model. There is for example one from Tectonic web site DML theory and practice.
In §3.3 after fig10 :
One additional element is missing which is the coil resistance.
From all of that, and it fits with my current experience, to reach high frequencies, all the other parameters equal :
In practice, this means for a given exciter, it will go higher frequencies with a stiff and heavy material.
I think it explains some questions opened here like :
For the one not too afraid by some math... As B = E.h³/12 and µ=rho.h with E Young modulus of the panel material, rho its density, h the panel thickness, it comes from (2)
Zm = 8.h².(E.rho/12)^.5
So for a given material, the mechanical impedance increase with the square of the thickness.
Does it explain the choice of thick material (ie 20mm EPS) and in consequence a large surface to reach a large bandwidth?
It might also explain the low performance of my panels made from 9mm XPS.
The reality is probably more complex because of the mechanical impedance is not constant with the frequency (not found good information about that for now) or because of the effect of the voice coil / panel interface but I think it gives some guide lines.
Some measurements show easily at least the mass or the mechanical impedance effect.
This is in the case of an exciter driven by a voltage source which is the general case with a standard amplifier.
If some are interested, I attach here a LT spice file of this simplified model
Below is the schematics
H1 and H2 are linear voltage dependent current sources.
For other value of R3, you can refer to the material sheet of the history file (see posts before)
Christian
With the standard loudspeaker, I was used to make simulations of filter based on the electrical model of the speaker. For DML, several papers propose a simplified model. There is for example one from Tectonic web site DML theory and practice.
In §3.3 after fig10 :
One additional element is missing which is the coil resistance.
From all of that, and it fits with my current experience, to reach high frequencies, all the other parameters equal :
- A low voice coil inductance is preferable
- A 8 ohm exciter is preferable (be careful : all the other parameters equal...)
- A low mass is preferable (see in a previous post the effect of an added mass)
- And last and something which new for me... a high mechanical impedance material will go higher. As given in §3 eq 2 :
In practice, this means for a given exciter, it will go higher frequencies with a stiff and heavy material.
I think it explains some questions opened here like :
- plywood has better high frequency extension than EPS. Acrylic even better. Unfortunately this goes against the efficiency (efficiency is related to B/µ³)
- Steve (Spedge) who is among the only one having 8 ohms exciters with low inductance and low voice coil mass gets very good results with EPS... not me (sad!).
For the one not too afraid by some math... As B = E.h³/12 and µ=rho.h with E Young modulus of the panel material, rho its density, h the panel thickness, it comes from (2)
Zm = 8.h².(E.rho/12)^.5
So for a given material, the mechanical impedance increase with the square of the thickness.
Does it explain the choice of thick material (ie 20mm EPS) and in consequence a large surface to reach a large bandwidth?
It might also explain the low performance of my panels made from 9mm XPS.
The reality is probably more complex because of the mechanical impedance is not constant with the frequency (not found good information about that for now) or because of the effect of the voice coil / panel interface but I think it gives some guide lines.
Some measurements show easily at least the mass or the mechanical impedance effect.
This is in the case of an exciter driven by a voltage source which is the general case with a standard amplifier.
If some are interested, I attach here a LT spice file of this simplified model
Below is the schematics
- R1 : electrical resistance
- L1 : voice coil inductance
- BL : force factor
- R2 : mechanical resistance (Rms) of the exciter
- C1 : compliance of the exciter (Cms)
- L2 : magnet mass (cancel L2 if the magnet is fixed)
- L3 : voice coil mass
- R3 : panel mechanical impedance.
H1 and H2 are linear voltage dependent current sources.
For other value of R3, you can refer to the material sheet of the history file (see posts before)
Christian
Christian.
My exciters are 4 ohms .
With my exciter, eps panel combination, the high frequencies do not reach the edge of the panel.
The hf is mostly produced in the central area ,especially if the cancellations in this area are delt with .
Ply and proplex for instance, with my combination or exciter and panel will reach 20k across the whole panel even at the edges.
Probably at a slightly lower volume, similar to the other frequencies.
I will make some plots of this ,to demonstrate the differences.
Even though the ply and and proplex show a higher output of HF across the panel,they sound lacking, I can only describe it as a restrained sound.
They lack a brightness or life to the sound ?
Podiums had the same sort of sound, the more I listened the more i noticed , which was probably why I preferred the sound from the back ?
It is strange when the measurements say one thing, but my ears say another.
I'm not saying that the heavier panels don't sound good.
The proplex panel for instance, is a very good all round performer with low colouration, no box or frame needed, simple, works perfectly.
If I was to hear this at an audio show , costing thousands of pounds, I would be impressed.
For me at home, I would still want to improve it a little.
Steve.
My exciters are 4 ohms .
With my exciter, eps panel combination, the high frequencies do not reach the edge of the panel.
The hf is mostly produced in the central area ,especially if the cancellations in this area are delt with .
Ply and proplex for instance, with my combination or exciter and panel will reach 20k across the whole panel even at the edges.
Probably at a slightly lower volume, similar to the other frequencies.
I will make some plots of this ,to demonstrate the differences.
Even though the ply and and proplex show a higher output of HF across the panel,they sound lacking, I can only describe it as a restrained sound.
They lack a brightness or life to the sound ?
Podiums had the same sort of sound, the more I listened the more i noticed , which was probably why I preferred the sound from the back ?
It is strange when the measurements say one thing, but my ears say another.
I'm not saying that the heavier panels don't sound good.
The proplex panel for instance, is a very good all round performer with low colouration, no box or frame needed, simple, works perfectly.
If I was to hear this at an audio show , costing thousands of pounds, I would be impressed.
For me at home, I would still want to improve it a little.
Steve.
Hi Steve
I'm still trying to determine exactly what Proplex is... Web results indicate that it is a corrugated ? Twin wall ? polypropylene floor protection sheet.
If that's the case surely it's relatively soft (like our Corflute) and would be an unlikely candidate for a DML panel... That's patently not what you found so I'm somewhat confused
Eucy
I'm still trying to determine exactly what Proplex is... Web results indicate that it is a corrugated ? Twin wall ? polypropylene floor protection sheet.
If that's the case surely it's relatively soft (like our Corflute) and would be an unlikely candidate for a DML panel... That's patently not what you found so I'm somewhat confused
Eucy
Hi Christian ..
Can you please explain further how you draw that last conclusion .. It seems upside down to me
Eucy
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Eucy.
I was confused too, it was not what I expected.
I posted this picture when I received them from JohnnoG.
I don't know what he used to cut the panel, but as you see , it does not chip or break .
It is designed to take a heavy pounding and weight.
It is not a lightweight panel, and I would say it has heavy self damping, with minimal self noise.
My low grade eps panels are soft and still produce a good sound, so I think maybe rigidity isn't that important?
I included an old frequency plot but I'm not sure if it was the 6mm or 4mm panel ?
Steve..
I was confused too, it was not what I expected.
I posted this picture when I received them from JohnnoG.
I don't know what he used to cut the panel, but as you see , it does not chip or break .
It is designed to take a heavy pounding and weight.
It is not a lightweight panel, and I would say it has heavy self damping, with minimal self noise.
My low grade eps panels are soft and still produce a good sound, so I think maybe rigidity isn't that important?
I included an old frequency plot but I'm not sure if it was the 6mm or 4mm panel ?
Steve..
Attachments
This is the proplex 4mm ,the one in my previous post was the 6mm.
The 4mm looks very similar to the correx type material, but I have not compared the two, so am not sure if they are the same ?
If anyone knows the answer , please let us know?
I think I have seen 3mm signage correx, which seemed quite flimsy, but I am not sure?
Steve.
The 4mm looks very similar to the correx type material, but I have not compared the two, so am not sure if they are the same ?
If anyone knows the answer , please let us know?
I think I have seen 3mm signage correx, which seemed quite flimsy, but I am not sure?
Steve.
