camarada78

BM-87 - A cardioid U87i inside a BM-8000 body
« on: July 28, 2020, 01:28:51 PM »
This past week I decided to fit a U87i circuit inside a BM-8000 body.

I did only the cardiod version because it was the capsule I had available. After some troubleshooting some stupid connections (thanks Delta for the tip), i manage to finish and test the prototype. The results are better than i expected!

very good looking microphone for 10-18 dollars. Mine had a very usable shockmount also. It's a steal.





Anything that is too stupid to be spoken is sung


camarada78

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #1 on: July 28, 2020, 01:29:38 PM »
inside 1
Anything that is too stupid to be spoken is sung

camarada78

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #2 on: July 28, 2020, 01:30:30 PM »
inside 2
Anything that is too stupid to be spoken is sung

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #3 on: July 28, 2020, 03:40:28 PM »
I am sure it works great, but that headbasket is acoustic nightmare. It makes huge dips in upper midrange, notch type dips, possibly larger than 10db. It messes with polar response as well, it is not cardioid most definitely.  It substantially  extends the time the sound waves need to reach the rear compared to the front.  Quite opposite of u87 head basket which is meant to be transparent. 

camarada78

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #4 on: July 28, 2020, 03:45:47 PM »
I am sure it works great, but that headbasket is acoustic nightmare. It makes huge dips in upper midrange, notch type dips, possibly larger than 10db. It messes with polar response as well, it is not cardioid most definitely.  It substantially  extends the time the sound waves need to reach the rear compared to the front.  Quite opposite of u87 head basket which is meant to be transparent.

I will test it during the week and comment.  Comb filtering might be bad. I will give some comments later.
Anything that is too stupid to be spoken is sung

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #5 on: July 29, 2020, 11:12:37 PM »
I am sure it works great, but that headbasket is acoustic nightmare. It makes huge dips in upper midrange, notch type dips, possibly larger than 10db. It messes with polar response as well, it is not cardioid most definitely.  It substantially  extends the time the sound waves need to reach the rear compared to the front.  Quite opposite of u87 head basket which is meant to be transparent.
What, if anything, could be done to fix it? Flattening the mesh?  Looks quite similar to what Blue uses except their head baskets are flat on one side. Actually the Kiwi is flat on both sides but still sticks out.
« Last Edit: July 29, 2020, 11:30:52 PM by Icantthinkofaname »

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #6 on: July 30, 2020, 12:27:54 PM »
The tube surrounding the capsule is too deep.  I moded  one to be thinner, it made a world of difference. Sometimes you want that notch, if the frequency is right it attacks sibilant  areas.

Blue has shallower tube, but also different capsule even though it's based on k67. Some are based on c12, but still different. Some Blue mics also have some of that dip going on. There is also more room around the capsule.

Blue uses very cool mod to standard chinese k67 with rotating disc instead of second half of cackplate. You can tune FR and PR this way.

https://groupdiy.com/index.php?topic=73182.0

Soyuz uses similar headbasket, but it's much tighter to the capsule. And capsules are not typical k67.

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #7 on: July 30, 2020, 03:33:38 PM »
Neewer sells (or used to sell) a mic called the NW-500 which looks similar but the headbasket seems to be smaller. I'd still want the grille to stick out a bit less. It doesn't seem to be available anymore on Amazon.

Below is a video of it:

https://youtu.be/YREILTxFpS8

There's a mic sold by Freeboss that looks interesting too, the model is FREEBOSS ES-4-SB and I'm attaching a picture of it.
« Last Edit: July 30, 2020, 05:23:52 PM by Icantthinkofaname »

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #8 on: July 30, 2020, 06:15:09 PM »
That looks way better.

shot

Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #9 on: July 31, 2020, 04:45:18 PM »
There's a mic sold by Freeboss that looks interesting too, the model is FREEBOSS ES-4-SB and I'm attaching a picture of it.

I have built FET847 mic into this body. Bought it on aliexpress for 30ish dollars. Don't know under which name they were selling it but it wasn't Freeboss.
Dissasembling the headbasket was tricky and I had to make custom capsule saddle to fit it inside. I remember that it took twice the time to fit the capsule in there than to assemble everything else!
I've "tested" it by playing pink noise from headphone to headbasket and it showed nice curve. No excessive dips or peaks.
And I really like that mic!

:)

Luka


Re: BM-87 - A cardioid U87i inside a BM-8000 body
« Reply #10 on: July 31, 2020, 06:25:03 PM »
I have built FET847 mic into this body. Bought it on aliexpress for 30ish dollars. Don't know under which name they were selling it but it wasn't Freeboss.
Dissasembling the headbasket was tricky and I had to make custom capsule saddle to fit it inside. I remember that it took twice the time to fit the capsule in there than to assemble everything else!
I've "tested" it by playing pink noise from headphone to headbasket and it showed nice curve. No excessive dips or peaks.
And I really like that mic!

:)

Luka
Yeah, the Freeboss version is also around $30 assuming you order the cheapest version.


 

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