That, I don't get. Some cymbals are 20" or more in diameter. How is that a point source if it has as much moving surface area as do probably most hand-held acoustic instruments?
Also, I don't see where room acoustics should necessarily be a problem. When I want to listen carefully to a speaker I listen in the very near field. I don't want to hear the room.
^ Doesn't take much, say even 5-10 meters away from the drum kit in a small venue vs 0.5-1m to change a couple dB.
Calculation method of absorption of sound by atmosphere air damping dissipation absorbtion high frequencies attenuation sound during propagation outdoors outdoor - sengpielaudio Sengpiel Berlin
Calculation method of absorption of sound by atmosphere air damping dissipation absorbtion high frequencies attenuation sound during propagation outdoors outdoor - sengpielaudio Sengpiel Berlin
Why do I owe you any of my tests and measurements for Damir's design? THD, IM, Multitone, group delay, SR, psrr, etc???
-RNM
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Dan is right best fit (usually at the high frequencies) will usually give enough rejection across the audio band that a good sound card and FFT analysis will do very well. A simple time domain view of the residual remains problematic.
Anything that allows you to look deeper into the distortion products of a device is going to be extremely helpful.
Until a newer, cheaper RTX is created, try using a sound card and tell us how many you go through testing amplifiers - while getting the data of course.
Okay, the RTX is not cheap, but given the alternatives the pricing isn't bad. I broke the bank buying one of these units, but it is so valuable that it is in use every single day. It would be fantastic if it were less expensive. While we're at it, can we also order up houses and cars that I can afford? So given that isn't going to happen, then design and build us an RTX-6001 as good, but a lot cheaper than what Jens brought to market. Please?
Until a newer, cheaper RTX is created, try using a sound card and tell us how many you go through testing amplifiers - while getting the data of course.
You don't, but when you say 'You should try it' then I would expect YOU to have tried it and have something to show. My mistake.
And worth reposting my goto recording when I want something that I know is completely natural Redbird (Redbird album - Wikipedia) . Three people in their living room with 2 or 3 guitars sitting round a stereo ribbon mic and just jamming away. No attempts have been made to remove anything so you can hear all the external noises as well. A nice tonic for a world where a lot of modern music is more processed than cheez whiz!
... just listened to a bit of that, on bandcamp.. Nice.... I'll try more after work....
That was an invite to provide a link so that we can all take a listen.....else wise your assertions are pure postulating.
Dan.
What's that supposed to mean? This is DIY after all, alternatives for dynamic range enhancement of the standard tests have been around for decades. No commercial DAC/AD combination is going to give exact repeatable answers at <-130dB if you insist on measuring the stimulus simultaneously. I did better than -140dB floor measurements 35yr. ago, sort of paid DIY.
They could be repeated with ANY soundcard (within reason).I would not find the RTX useful because the software I prefer does not support ASIO. The QA400 has pretty good performance, I don't see adding a mode where it becomes a USB IO device for external software as rocket science.
Kevin has an RTX from the group buy, I would be glad to demonstrate.
I think Scott's comment on using the QA400 with usb I/o software would do very nicely and be very much lower cost.
very THx-RNMarsh
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Hi Scott,
It means that you can use a normal sound card for this, but without a front end, many will probably die a horrible death. It is DIY, and part of DIY is recognising the limitations of a chosen solution. Even an attenuator for a sound card needs to be frequency compensated. I know because I tried that.
My comment was in response to the statement that the RTX was too expensive, which I did quote so you would know what I was talking about. Of course, it wouldn't be suitable for everyone for various reasons as you pointed out. Hey, if I had the money, I'd be using an Audio Precision or a Keysight U8903B for this. I can't even come close to be able to afford one, so the RTX is the best I can do. Coupled with the right software, it might just work out for me. One thing it isn't is too expensive compared to the other testers. Having said that, with either of the full price solutions I would be off and running already making useful measurements.
-Chris
It means that you can use a normal sound card for this, but without a front end, many will probably die a horrible death. It is DIY, and part of DIY is recognising the limitations of a chosen solution. Even an attenuator for a sound card needs to be frequency compensated. I know because I tried that.
My comment was in response to the statement that the RTX was too expensive, which I did quote so you would know what I was talking about. Of course, it wouldn't be suitable for everyone for various reasons as you pointed out. Hey, if I had the money, I'd be using an Audio Precision or a Keysight U8903B for this. I can't even come close to be able to afford one, so the RTX is the best I can do. Coupled with the right software, it might just work out for me. One thing it isn't is too expensive compared to the other testers. Having said that, with either of the full price solutions I would be off and running already making useful measurements.
-Chris
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