Townsend Labs Sphere Hacking
« on: February 12, 2019, 07:22:22 PM »
After seeing a video on YouTube, and couple more images i am 99% sure Sphere uses regular 797audio k67 like Behringer B2 for example. Red/Yellow wire combo is another giveaway. Saddle looks like 797audio as well. Capsule graphics in the manual look exactly like 797audio capsule. So i changed the capsule in my dual output mic for 797 audio one.

My Quick Dual Output Mic:
https://groupdiy.com/index.php?topic=69193.0

Sphere mic closeup:





By measuring the Sphere plugin and all the emulations against expected curves, and some of the mics i have measured in the past i came to conclusion that the original Sphere mic has high end attenuation circuit built in. It is similar to the u87, but a bit more aggressive.  Their Sphere Diffuse model  actually compensates for this roll off. It probably serves as a safety feature if someone tries to use 3rd party mic, and for some off axis modeling explained in the manual. The curve is easy to extract from the plugin.

Long story short, if you use dual output mic with k67 from 797audio and apply this kind of eq curve before the plugin you get the Sphere mic for cheap. The plugin is still free for download



This setup matched two vintage u87s i have measured within 0.5db in every pattern for example.  Their flat model both in cardioid and omni matches my ECM8000 response, less low end on omni naturally, sm57 is very close as well. my c12 and u47 replicas are scary close.

Again, even without any emulation with a DIY stereo out mic free Sphere plugin is extremely useful tool.
« Last Edit: February 12, 2019, 08:36:28 PM by kingkorg »


Re: Townsend Labs Sphere Hacking
« Reply #1 on: February 14, 2019, 11:29:18 AM »
Nice detective work! Bravo.

I've been contemplating this very same topic. Please continue to update this thread with your discoveries. :)

Re: Townsend Labs Sphere Hacking
« Reply #2 on: February 14, 2019, 03:33:05 PM »
Well i hope ill get my hands on one, and measure it to be sure.

Until then i have fine tuned HF attenuation curve, and got some crazy results.
Here are few examples. Right click, open in a new tab.

Real vintage u87 against my Sphere. Blue is Sphere.


My u47 clone against Sphere. Green is Sphere model


My c12 clone with Tim Campbells capsule against Sphere.  Magenta is Sphere model. Slightly darker, but the curve is there.

Re: Townsend Labs Sphere Hacking
« Reply #3 on: February 16, 2019, 02:41:35 PM »
Pretty slick, Slick.

Did you wire the output to a 5 pin XLR or just direct wire a couple of mic cables to the PCB's? 

Next weekend, for laughs I may try to throw together a dual output mic like this with a couple of pimped alice boards. I think I still have an old 32mm K67 taken out of an Apex 460 to try it with for the time being.

Re: Townsend Labs Sphere Hacking
« Reply #4 on: February 16, 2019, 03:28:32 PM »
I just used dual cable from pcbs to two xlrs.

I can send you this high end deemphasis curve i've fine tuned. I used Voxengo CurveEQ. It is CSV file, so it can be converted to impulse response, or loaded in some other VST.

Re: Townsend Labs Sphere Hacking
« Reply #5 on: February 22, 2019, 12:53:17 AM »
Can't give away the source, but i got confirmed that the capsule is indeed 797 audio capsule.

The next thing i suspect that microphone it self actually might have built in AD/DA converter and some kind of IR latency free loader that fine tunes each capsule to get most adequate pre emulation curve. Just like the one i found and use with Voxengo CurveEQ.

bremusound

Re: Townsend Labs Sphere Hacking
« Reply #6 on: February 22, 2019, 06:16:01 PM »
Nice project!!
Do you know if it's the 3 or 6 micron 797 capsule?
Thanks

Re: Townsend Labs Sphere Hacking
« Reply #7 on: February 22, 2019, 06:50:30 PM »
Unforyunately not, but they dont differ much. It's mostly tiny transient response difference, noise, and max spl.  Frequency response should be the same.


 

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