Delighted to hear your insights, this is largely new to me, and interpreting the results is difficult for me. For the TD-4001 there is amazingly little information (I mean measurements) I am hoping to remedy that by sharing what I have measured when I am least partially confident I know what I am doing. (Definitely not always the case!!)
I can see some definite benefit to your improved adapter particularly compared to bolting two of the off the shelf adapters together. Leads me to wonder just how optimal mine are, but there is not much I will be able to do in the short term about that. Need to understand whether improvement is possible and then how to implement it.
I can see some definite benefit to your improved adapter particularly compared to bolting two of the off the shelf adapters together. Leads me to wonder just how optimal mine are, but there is not much I will be able to do in the short term about that. Need to understand whether improvement is possible and then how to implement it.
imo a superior method for distortion analysis is stepped sine with RTA in REW. Also use a good quality audio interface, a low distortion amp and a very high quality microphone like M23. Otherwise results are questionable.
Yes, it's a good choice and it needs to be considered. Kevin is indicating this with the dedicated interface.
Nevertheless, my response hasn't changed.
The corner diffraction is detrimental to the vertical perspective. In addition...
Clearly it plays catch-up where diffraction is involved.. this essentially makes the point brought up by profiguy and others.
There is a solution. While this horn calls for a line source, you could use a transitioning phase plug
Waving your hands and stating things as facts does not make them true. If you have something to demonstrate whatever point you are trying to make, great, otherwise I find this sort of back and forth with you to go nowhere.
They would be irrelevant as you have now become the second person I feel I have to ignore.
Thank you for this insight. This, and the measurement of standing waves likely caused by diffraction in the "simple" throat adaptors, do shed a new light in my understanding of the throat adaptor problem. So a better adaptor, besides loading the driver well and smoothly making the circular driver wavefront rectangular, would also transition a spherical spreading at its entrance to a cylindrical spreading at its exit. Making sense? If it does, then I will take a stab at testing this idea.
The EMX-7150 is a rather good measurement mic:
FEATURES
https://www.isemcon.net/ashop/product_info.php?products_id=57
A review can be found here:
https://www.isemcon.com/datasheets/iSEMcon EMX-7150.pdf
Not extactly cheap either, but roughly half the price of a M23. Do not know about the availability in US though.
FEATURES
- Frequenzgang 10Hz-20kHz
- Empfindlichkeit 6mV/Pa typ.
- Matching Toleranz ±0,5dB Linearität, 1mV Mikrofonempfindlichkeit @94dBspl
- Dynamikumfang ~30 >140dBspl
- 3% Verzerrungsgrenze 145dBspl typ.
- Kalibrier-Messschrieb und Kalibrierdaten von my.isemcon.com
- IEC 61672 Klasse 1 Frequenzgang
- Abmessungen: Mikrofon-Ø 1/4" (7mm); Gehäuse-Ø 0.75" (19mm); Gesamtlänge 6" (152mm)
- Gewicht 0.3oz (75 grams)
https://www.isemcon.net/ashop/product_info.php?products_id=57
A review can be found here:
https://www.isemcon.com/datasheets/iSEMcon EMX-7150.pdf
Not extactly cheap either, but roughly half the price of a M23. Do not know about the availability in US though.
Makes sense to me.
https://www.jochenschulz.me/en/blog...7150-vs-behringer-emc8000-vs-beyerdynamic-mm1
The TM1 is supposedly quite good and a step up from lower grade mics.
Most do well enough from a FR perspective with calibration, but low self noise and distortion performance are things that only the more expensive mics really have.
Measuring the true distortion performance of anything at home is going to be difficult unless you can find a way to lower the noise floor regardless of the mic you use.
The EMX-7150 seem to be out of stock in the U.S at the moment. The M23 is too expensive to consider for a dilettante dabbling in acoustic measurements on a single speaker system in his basement. I am still debating whether or not the UMIK-2 is not enough for my needs.
Interface being considered Motu M2 or M4.
Mics
Beyer Dynamic MM1 ($199)
EMX-7150
Audix TM1Plus (on sale at $299)
?
@fluid I removed my post and replaced it, while I did so you posted a reply to my questions.. Oops...
Interface being considered Motu M2 or M4.
Mics
Beyer Dynamic MM1 ($199)
EMX-7150
Audix TM1Plus (on sale at $299)
?
@fluid I removed my post and replaced it, while I did so you posted a reply to my questions.. Oops...
Funny you mention room noise. This is a really quiet room, and most of the time the noise floor I am measuring is the mic itself. There are exceptions like when the heat is running, steam boiler increases room noise floor substantially, laundry really noisy in the next room over. We live in an extraordinarily quiet neighborhood, very little evening traffic and most of our neighbors go to bed quite early, my wife is quiet. A B&K SPL meter, recently calibrated and borrowed from work some years ago was not able to measure the noise floor in here during my usual listening hours, which is kind of nice. The power and isolation transformers produce most of the audible noise. Quiet might be one of the very few things this listening room has going for it.
Once I retire I will probably renovate the room, and one of the planned improvements is to install mineral wool between the floor joists supporting the living room on the GND floor.
The most I have measured in here was around 30dBA. (During times I would normally be listening)
Once I retire I will probably renovate the room, and one of the planned improvements is to install mineral wool between the floor joists supporting the living room on the GND floor.
The most I have measured in here was around 30dBA. (During times I would normally be listening)
Motu M4 is a great interface for measurements and recording. There are 2 versions on the market. The older one is US made and the later chinese. I prefer the US made one due to the way its assembled. Both perform equally well though. For the fact the M4 is USB bus powered, its amazing how low the noise floor and low level THD is.