Topic: I recently purchased a Audio-Technica BP4029 microphone but..

[gihl]

I recently purchased the Audio-Technica BP4025 and BP4029 microphones. Both are brand new products.
While inserting the XLR cable into the BP4029, I noticed that the inner surface of the BP4029's connector looked reddish-brown.
So, I compared it with BP4025. As shown in the attached photo, the internal surface of BP4025 is clean and shiny silver.
I wonder if BP4029 is in normal condition.

[rocksuitcase]

Appears to just be corrosion to me. Use some contact cleaner with a swab. Caig Deoxit has a formula which also lubricates the insides while cleaning

[Gutbucket]

I think its just a lack of black paint on the inside of the brass tubing. 

[illconditioned]

Would love to hear some AT stereo mics.
I've got several of the AT822/825 and love them.

[gihl]

I tried rubbing the inside of the microphone connector with a cotton swab several times, but it didn't pick up anything.
Anyway, I sent an inquiry email to Audio-Technica.
Thanks for all the replies. 

p.s. These days, I'm playing around with the Voxengo MSED Plugin in Adobe's Audition for basic Mid-Side adjustment.
Actually, I'm just learning the Mid-Side. However, I intend to mainly use it for recording distant cityscapes.

[DSatz]

I have a 4029 in one of my storage rooms and was just there this evening, so I looked at its connector end--it looks like yours does in the picture.

[gihl]

I have a 4029 in one of my storage rooms and was just there this evening, so I looked at its connector end--it looks like yours does in the picture.

Thank you for the information!

[Ronmac]

It looks normal, to me. They likely used different brass alloy (copper/zinc mix).

[gihl]

Thanks!

[DSatz]

slightly off-topic, but if you are just now exploring M/S stereo recording of music, I strongly recommend learning what you can do by equalizing the "S"-channel signal, especially at low frequencies. When you record with a coincident or closely-spaced pair of directional microphones, you're opting for image stability over spaciousness. That usually makes sense, since with widely spaced microphones it's very distracting when a particular sound source seems to jump from one loudspeaker to the other during playback (e.g. a solo soprano with orchestra, if she simply turns her head from side to side a little).

But you shouldn't have to give up all sense of the size of the room; big spaces just feel nice, and that's largely conveyed by the uncorrelated low-frequency information in the recording. Unfortunately since low frequencies have long wavelengths, two coincident microphones will tend to pick up the low frequencies very nearly in mono--all the more so if they're cardioids and/or their polar pattern broadens out at low frequencies and/or the angle between them is too narrow, as it very often is. But with M/S recording you actually have the difference information right there as one of your microphone signals (the "S" channel), and you can boost the low frequencies (room noise permitting) to recover some of the benefit that a more widely spaced pair, and/or a pair with better low-frequency directivity, could have given you.

That has its limits, and sometimes you want to make a corresponding, or partly corresponding, bass rolloff in the "M" channel, but it can really make the sound more pleasant and fun, and it's not necessarily dishonest on a technical level.

[gihl]

Thank you for your advice.
But I'm just an ordinary amateur who likes to record ambient sounds of the city, so I don't fully understand your explanation.
Anyway, I'll learn step by step.

[DSatz]

OK, sorry--what I meant is, the 4029 has a switch that lets you record the Mid and Side channels, then matrix them later on to stereo left and right. If that's what you're doing (and I recommend it if possible), I'm suggesting that you play with boosting the bass in the "S" channel before you matrix to stereo left and right. Like, try +4 dB at 100 Hz (shelving, not peaking) just to get a sense of what's possible. The whole spatial picture can open up and make the listening experience a lot more fun.

It also helps if your loudspeakers aren't too close together--with you and them forming a an "equilateral" triangle or even a bit wider if your room is big enough.

P.S.: I live in New York City and love it when I get a chance to record the sounds around here. When Louis DeJoy made the Post Office replace all the outdoor mailboxes with the new, supposedly more secure kind, while there were still the old kind that I grew up with, I made some recordings of the metal flap closing after you put a letter inside one of them, because I didn't want to forget what that sounded like.

[Gutbucket]

Love that sound! 

Now wanting to assign it to my email send button.

[gihl]

Thank you for the practical explanation.
If you don't mind, can I ask you to capture how to boost the base at 100 Hz on Adobe Audition or another audio editing program? Sorry..

[DSatz]

"step zero" is to save off a copy of your unmodified, original files first. -- I have Audition CS 6, not the Creative Cloud version. According to the menus I have, I'd suggest:

[1] Choose the recorded "S" channel in Edit -> Enable Channels -> (whichever channel has the "S" signal--normally the right channel, but your setup may differ). Then:

[2] Effects -> Filter and EQ -> Parametric Equalizer. This gives you a set of adjustable controls plus a graph that shows the net effect of the combination you choose. On the left side there's a button for "HP" followed by one for "L". Activate "L", then to make the effect more obvious than you may want to use eventually, but just for the sake of experiment and ear-training, maybe set the Frequency to 150 for starters, set Gain to maybe 6 dB, and the Q/Width control can go either way but I would suggest the one with the sharper effect (the icon on the button has sharper corners). I've attached a screen capture of the dialog the way it looks in my version.

-- To convert M/S to stereo L/R it's a little non-intuitive; you'd use Effects -> Amplitude and Compression -> Channel Mixer. I use the values shown in the two smaller screen captures, which I've saved as a preset. Note that there are two tabs in the dialog (L and R), which both need to be set, and that when setting the mix for the R channel output, you need to check the checkbox under "Invert" for the R channel input.

--best regards