- Thread Starter
- #21
Thanks for your explinations.
I'm already familiar with the background of binaural (dummy head) recording. And I think you are totally right on most aspects.
As far as I know the GRAS ears can be ordered via their website or specialized distributors in your country. I haven't required a quote, yet. But as far as I know their business model the price will be out of the league for ordinary mortals. Especially for the newest generation of anthropomorphic pinnas with enhanced ear canals.
The pair of ears I will use is shown above. It is a symmetrical pair of soft silicone ears. The size is just right with 67 mm top to bottom lobe. Some other models I got in the past were much to large and had trouble fitting inside some ear cups. I do still have some concerns about the 3D-printed adapter and the resonances it might introduce. Still, probably better than simply sticking the ear simulator right to the ear canal entrance. Afaik the 60318-4 is designed to be coupled close to the ear drum reference point (where an in-situ microphone would sit).
As you can see I also tried molding my own personalized pair of silicon ears. Unfortunately the compound the audiologist used was not that optimal for detailed impressions of the human ear. And even if it was, further processing, shaping and molding the replica is really an art on its own. Not so great if you don't have the practical experience and technical equipment (like a vacuum chamber for degassing).
This is why I will probably stick with the model shown above. It might be kind of random and a bit simplified in its shape. But still better than simply measuring on a flat coupler without any pinna interaction.
I know that - after all that - it is nearly impossible to hit the same baseline as the industry standards do. But I will try my best to come at least close to it, as reproducable as possible.
The mics I consider at the moment are the Dayton iMM-6 and the Superlux ECM 888. They are not the most sophisticated measurement mics, for sure. But with some calibration they will probably do the job. I will definitely have to apply some compensation for the 0° incidence in case I want to get near to the reference baseline. As I already suggested above, ear simulators are tuned for pressure response. For most measuring mics this response will be most equal to the 90° incidence.
Noise floor as a parameter of dynamic range will play a role when I want to measure things like crossfeed. Distortion measurements would be great as well. But that's where the cheap capsules and their preamps really limit. The best I could find within my price range is the Line Audio OM1 with 0.5% at 133 dB. Sadly it will not fit the coupler due to its nozzle.
The Primos are great in price and performance, especially for their 80 dB SNR. High SPL is a weakspot, though. Even with advanced circuitry and 3-wire hacks.
Regards,
P48
I'm already familiar with the background of binaural (dummy head) recording. And I think you are totally right on most aspects.
As far as I know the GRAS ears can be ordered via their website or specialized distributors in your country. I haven't required a quote, yet. But as far as I know their business model the price will be out of the league for ordinary mortals. Especially for the newest generation of anthropomorphic pinnas with enhanced ear canals.
The pair of ears I will use is shown above. It is a symmetrical pair of soft silicone ears. The size is just right with 67 mm top to bottom lobe. Some other models I got in the past were much to large and had trouble fitting inside some ear cups. I do still have some concerns about the 3D-printed adapter and the resonances it might introduce. Still, probably better than simply sticking the ear simulator right to the ear canal entrance. Afaik the 60318-4 is designed to be coupled close to the ear drum reference point (where an in-situ microphone would sit).
As you can see I also tried molding my own personalized pair of silicon ears. Unfortunately the compound the audiologist used was not that optimal for detailed impressions of the human ear. And even if it was, further processing, shaping and molding the replica is really an art on its own. Not so great if you don't have the practical experience and technical equipment (like a vacuum chamber for degassing).
This is why I will probably stick with the model shown above. It might be kind of random and a bit simplified in its shape. But still better than simply measuring on a flat coupler without any pinna interaction.
I know that - after all that - it is nearly impossible to hit the same baseline as the industry standards do. But I will try my best to come at least close to it, as reproducable as possible.
The mics I consider at the moment are the Dayton iMM-6 and the Superlux ECM 888. They are not the most sophisticated measurement mics, for sure. But with some calibration they will probably do the job. I will definitely have to apply some compensation for the 0° incidence in case I want to get near to the reference baseline. As I already suggested above, ear simulators are tuned for pressure response. For most measuring mics this response will be most equal to the 90° incidence.
Noise floor as a parameter of dynamic range will play a role when I want to measure things like crossfeed. Distortion measurements would be great as well. But that's where the cheap capsules and their preamps really limit. The best I could find within my price range is the Line Audio OM1 with 0.5% at 133 dB. Sadly it will not fit the coupler due to its nozzle.
The Primos are great in price and performance, especially for their 80 dB SNR. High SPL is a weakspot, though. Even with advanced circuitry and 3-wire hacks.
Regards,
P48
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