Topic: Naiant X-8S microphone (switchable 8/card/omni; or x-former 8 only)

[Gutbucket]

http://naiant.com/studio-electronics-products/microphones/x-8s-multipattern-condenser-microphone/

I ran a Naiant X-8S for the first time last weekend, used as the side microphone in an M/S pair.  Worked very, very nicely.  Upon listening to it both alone in isolation and as matrixed with the Mid through a M/S decode with an appropriate ratio dialed in, I was pleased to find it sounding quite natural, and was somewhat surprised to find it had a more authoritative bass response than either the hypercardioid Mid mic I was using (a DPA 4098H, which rolls off significantly, like most typical miniature super/hypers), or the high-quality supercardioids I had flanking the M/S pair (MG M210, which has a more substantial low end response and perhaps a lower roll-off corner frequency, somewhat similar to the response of the Schoeps MK41).

I'll try and get some samples together for anyone interested in hearing them, but it may take a while before I get a chance to do so.  Disclaimer- This was an amplified PA recording of a band in a okay sounding medium sized club from just in front of the soundboard.  A rather typical situation by live music taper standards, but not something acoustically delicate, direct or pristine.

Quoting the Naiant webpage description- "The X-8S is available in two versions; the standard output which enables multipattern and stereo/dual capsule operation, and transformer output which is bidirectional only."

My pair of X-8S are the transformer output version, so as to be able to use them as figure-8s into an unbalanced input.  Last weekend I was running the mic into a balanced input recorder, powered via P48.  Doing that is straightforward, just use a standard balanced mic cable. Next weekend I plan to use one into an unbalanced input preamp, 9V powered.

"The standard output X-8S does not sum the opposing signals from its two capsules internally in bidirectional mode, so a balanced input microphone amplifier is required to generate a bidirectional signal.  For use with an unbalanced input amplifier with external phantom power supply, a balun transformer should be used between the phantom supply and the unbalanced input.  The X-8S may also be supplied with a transformer-balanced output (such that an inline transformer is not required); however, that option will limit the X-8S to bidirectional operation only."

Question for Jon-
How do I correctly wire a 3-pin XLR to 2-wire cable to do that?

Figured I'd open a thread and ask here so that others wanting to do the same can reference this thread.

[Gutbucket]

Thanks for the super quick response.  That's as I assumed, connecting negative signal and ground.

Any reason to connect pins 3 and 1 at the supply end rather than the mic end?  Somewhat better interference rejection even though unbalanced?  This will be an approx. 3' long run.  I'm just not sure what cable I have on hand to make something up in time, and may only have 2-conductor.

[Gutbucket]

Dang.  Appears I misunderstood the powering requirements.  For this particular application, the plan was to run this into a 2-wire preamp providing ~9V PIP, without needing additional devices.  This setup needs to be very compact, and it would be unfortunate to need an additional device to power these microphone(s).  I'm now coming to the realization that is not possible.  Correct?

Checking the specifications on the web-page, I now see you specify +12V to +48V Phantom power.  That leads me to assume the mic needs to see an isolated +12V at pin 2 and pin 3.  As it seems powering via 2-wire 9V PIP is not possible, could I rig up a battery box using two 9V alkalines, using one for each leg, and capacitor coupling pin 3 and pin 1, or is that insufficient voltage?  Now scheming on what I can do easily with parts I have on hand before the weekend.

I'll certainly get good use out of these for recording setups using balanced input recorders, yet I must admit I was thrilled thinking I'd finally found a figure-8 which would work with super compact 2-wire PIP gear.

[Gutbucket]

I believe I asked in the previous thread (couldn't locate it anymore) if the switchable version of the X-8S could be powered using both channels of a 2-wire preamp/supply, and your answer after some thought was that it could not.  Does the transformer version make doing that a viable option?  Assuming 9V is sufficient (perhaps with reduced sensitivity and SPL handling), can I power the mic using both preamp channels, then tap the differential signal after the preamp by leaving the preamp's output ground floating, feeding the unbalanced input of the recorder with the + signal from channel 1, and using the - signal from channel 2 as input signal ground?

If so, It seems I could simply make two custom cables:
1) A mic cable with a mini plug at the preamp end and XLR at the mic end (wired- Tip to 2, Ring to 3, Sleeve to 1).  Pin 2 feeds channel one signal input, pin 3 feeds channel two signal input. Pin 1 to preamp input ground.
2) An interconnect cable between preamp and recorder with miniplugs at either end- Tip to Tip, Ring to Sleeve, with no Sleeve connection at the preamp's ground output.  Preamp channel one signal out to recorder signal input, preamp channel 2 signal (inverted) to recorder input ground.

If that would work, I assume the gains of the two preamp channels would need to be very closely matched.

[Gutbucket]

Thanks Jon.  I'll give that a try.

[backwhereubelong]

You guys are AMAZING.  I don't understand a lick of that (wish I did) but I have mad respect for great minds that do.  I've learned so much from being on this site.

[The Other Chris]

You guys are AMAZING.  I don't understand a lick of that (wish I did) but I have mad respect for great minds that do.  I've learned so much from being on this site.

This. A thousand times this except I still haven't learned shit

[backwhereubelong]

You guys are AMAZING.  I don't understand a lick of that (wish I did) but I have mad respect for great minds that do.  I've learned so much from being on this site.

This. A thousand times this except I still haven't learned shit

You've probably forgotten more than I'll ever learn.  LOL. 

[tnelson]

So GB, have you had a chance to complete and test this experiment? A compact high quality M-S rig would be hugely useful. Good luck!

[Gutbucket]

Short answer is it worked, with no obvious problems, just not sure yet how well.  These are on-going experiments for me.  Nothing conclusive yet. Haven't really had the opportunity to play around with the resulting files.

Longer technical answer-

I had a recording opportunity the evening following my query to John above, and another 2 weeks later.  Since these were quick proof-of concept type tests I ran to the dollar store, bought a pair of one dollar headphones to scavenge the stereo miniplug cable, and soldered up a couple XLR connectors to power the two X-8S "single ended" (floating pin 3, grounding pin 1, +9V applied to signal pin 2) though an unbalanced 9V preamp (a Church Audio CA-UGLY v1). Sensitivity was reduced as expected, so I set gain on the preamp to the maximum available ~+20dB.  That worked, with no obvious frequency response problems, self noise problems, or interference noise problems apparent on a few cursory quick listens to the X-8S channels.  However I don't currently have a computer setup with audio editing software on it so I haven't had a chance to manipulate the files as necessary for actual listening and assessment as M/S pairs in combination with the boundary/baffled omni mids.  I only listened to make sure it worked without obvious problems.

These files were recorded on a second small 4 channel recorder run concurrently with the primary recorder, and a delayed copy of the intended Mid mics from the first machine were routed to that second recorder.  The headphone/monitor line out from recorder one was routed to line-in of recorder two, and the A>D>A>D delay inherent in that signal chain caused a delay between the Mid files and Side files recorded on the second machine.  That was expected.  I'll either delay the X-8S files to time align them with the Mid files recorded on the same machine, or use the copies of the Mid files recorded on both machines to help sync the X-8S files with the files from the first recorder.  Wrap your head around that one for a minuite.

Yeah, a crazy convoluted setup requiring post work to listen to correctly, but these are just tests to see if perusing this idea further is worthwhile, and the only way I could record a third pair of mics with a relatively small pocket-able rig using a second DR2d, which didn't compromise my standard 4 channel setup.

^
Please keep in mind that this is not Jon's recommended powering arrangement for these mics.  I plan to run these again in a couple weeks at an outdoor music festival with a proper balanced connection and P48 powering, similar to my first test recording with them, but as part of a different multi-microphone array.  That will be recorded into a DR-680 so there will be no need to do the two recorder sync and time alignment thing.

[Gutbucket]

More on the arcane setup above, altered slightly the second time around-

The second trial run I changed the routing by mult'ing the center omni Mid mic signals just after the preamp using a 'Y' adapter to send it directly to the inputs of both DR2d recorders, instead of recording the monitor out from the first into the second. 

Doing that avoided the A>D>A>D time delay in the Mid files recorded to the second machine which was recording the X-8S mics.

However, absent a computer with audio editing software loaded, I still can't listen to the M/S pairs directly using the built-in M/S playback decoder on a recorder because the two Mid files make up one stereo file on the DR2d, and the two X-8S files make up the second stereo file.  I may be able to use SoundDevices Wave Agent (which is loaded on the computer) to split these to mono files, swap and recombine them to stereo files, then play them back on a recorder which has a M/S playback decoder (DR2d does not, but R-44 and DR-680 both do).  Or I should just load and editor and do it right on the computer.

This concludes the "more information than anyone cares about" post.

[tnelson]

Definitely worth pursuing....It would be so useful to have an ultra compact but high quality M/S rig like this with simplified powering and cabling requirements. The ability to monitor M/S is one of the great things about the SD 7xx recorders, but just about everything associated with that is substantially up there in $$ and size/weight, compared to your experimental kit.

[Gutbucket]

For most folks, any balanced input recorder with P48 is all that is needed to run the X-8S as the Side mic in a M/S pair.  It's all the other stuff I'm doing which make it complicated, but it needn't be.

Besides being out of my budget range, the SD 7 series is simply too large for this application. For my setups the DR-680 has sufficient channel count and the decoding functions, but is likewise too large.  My R-44 can decode, but doesn't have the necessary channel count and is also too large anyway.  DR2d has been the best fit by far, so far.  But understand that my application is unusual in that I'm doing multichannel surround recording. Ideally, a pocket-able 6 (or 8 ) channel input recorder is needed. I imagine one currently under development and await delivery by a mermaid riding a unicorn.

If perusing this particular application further I'll build a proper battery box supply for the mic based on Jon's powering instructions.

[lsd2525]

For most folks, any balanced input recorder with P48 is all that is needed to run the X-8S as the Side mic in a M/S pair.  It's all the other stuff I'm doing which make it complicated, but it needn't be.

Besides being out of my budget range, the SD 7 series is simply too large for this application. For my setups the DR-680 has sufficient channel count and the decoding functions, but is likewise too large.  My R-44 can decode, but doesn't have the necessary channel count and is also too large anyway.  DR2d has been the best fit by far, so far.  But understand that my application is unusual in that I'm doing multichannel surround recording. Ideally, a pocket-able 6 (or 8 ) channel input recorder is needed. I imagine one currently under development and await delivery by a mermaid riding a unicorn.

If perusing this particular application further I'll build a proper battery box supply for the mic based on Jon's powering instructions.

FWIW, it only has 4 channels, but the DR60 will do M/S........pretty small form factor

[Gutbucket]

Not small enough.  Regardless I don't need M/S decoding on the recorder anyway, I just need additional recording channels.   Using a recorder for M/S playback decoding (which needn't be the same machine used for recording) is simply a work around for test listening until I get a computer setup with editing software again.

But yes, that recorder should do fine for this for most folks.