Possible Moron DIY: Headphone Switch

[Suntower]

Hi,

Just read the Gear Geaking column about 'headphone phase' and it got me thinking (dangerous, right?) I want to create a gizmo to do two things:

1. When I record myself singing I use the one ear headphone thing. And even when I squeeze the other ear to the side of my head to muffle the leakage -still- sometimes gets into the mic.

2. I'd like to make a headphone phase switch a la the Gear Geek column.

So... I was wondering
a) if someone makes a little a little in-line box (like Whirlwind used to make for their el-cheapo DI transformers) and

b) if there was a ready-made switch I could place in said box which would disable ONE channel of the headphone.

c) if there was a ready-made phase-reversal switch I could place in said box. I assume this could also be passive, right?

Anyhoo, I want a case and circuit that is reliable and cheap.

Maybe there is already something like the above on the market? Or is there more to it than I'm thinking... I mean, does putting these switches in the signal path do something bad to a headphone sound? (That's the moron part, I expect.)

TIA,

---JC

[The Scum]

Are you looking for the reversal and one side kill to be active intependently? You can use either, or both, just by hitting the corresponding switch?

If you can deal with the phase reversal only when the one phone is connected, it's easy and passive.

But it's not so easy to do if you need reversal when both ears are going.

[Suntower]

Independently. I just was hoping to have both functions in one box to save space and I guess. cut down on noise.

The phase thing is more curiosity... I just never experienced it before.

I actually -need- the channel cut-out switch. If I can't have both I only want this one.

TIA,

---JC

Are you looking for the reversal and one side kill to be active intependently? You can use either, or both, just by hitting the corresponding switch?

If you can deal with the phase reversal only when the one phone is connected, it's easy and passive.

But it's not so easy to do if you need reversal when both ears are going.

[dfuruta]

If you need to flip the polarity of the sides independently in between the headphone amp and the phones, you'll need to use active circuitry or re-wire your headphones.

To turn off either side is easy; per side, use an spst switch with one connector coming from your headphone amp and the other connector going to the + wire of the headphones. Leave the ground connected.

What's your chain going to the headphones? It would be easier to flip the polarity prior to the headphone amp, potentially.

[Suntower]

Thanks. I guess I'll avoid the phase thing.

But wrt may main request: turning off one side of headphones switch. Does someone have a source for an in-line box (a la Whirlwind or Proco) for the SPST?

I don't want some clunky footswitch or table box that will inevitably get knocked over or stepped on. As stupid-simple as this idea is, if it isn't -convenient- it's pointless to do. I'm CONSTANTLY whipping headphones on/off so the ergonomics matter.

TIA,

---JC

If you need to flip the polarity of the sides independently in between the headphone amp and the phones, you'll need to use active circuitry or re-wire your headphones.

To turn off either side is easy; per side, use an spst switch with one connector coming from your headphone amp and the other connector going to the + wire of the headphones. Leave the ground connected.

What's your chain going to the headphones? It would be easier to flip the polarity prior to the headphone amp, potentially.

[ashcat_lt]

I think that all of this is easier done on the other side of the headphone amp. Are you ITB or out?

Also, I either missed or have not yet received whatever article you're talking about. Are we inverting the polarity of both phones at the same time? Why?

[Suntower]

I'm ITB.

I'll try to make this simple as possible. IDEALLY, what I want is an enclosure the size of a female XLR connector, with an instrument jack on each end and a little SPST switch sticking out the side which simply shorts one side of the stereo signal.

How can I make something like -that-?


AFA the Gear Geeking article: http://tapeop.com/columns/gear-geeking/108/

See 2nd paragraph (boy that guy writes long paragraphs.)

Maybe this is too elaborate to put into the same gizmo.

TIA,

---JC

I think that all of this is easier done on the other side of the headphone amp. Are you ITB or out?

Also, I either missed or have not yet received whatever article you're talking about. Are we inverting the polarity of both phones at the same time? Why?

[The Scum]

If you've got headphones that you could take apart and put some switches in the earcups, we can do the polarity reverse. Old Koss K4's or K6's would work...newer, smaller phones will be tougher.

But it's hard to do the polarity flip upstream, because both of the speakers in the 'phones share a common ground.

It sounds like Andy was just using the polarity switch on the preamp.

But simply killing one or the other side of the phones with a switch isn't too tough. I'll put together a parts list and a recipe tonight or tomorrow.

[ashcat_lt]

Oh yeah, I remember that article now! It is a good idea, but again, I'd probably just invert the hardware send from Reaper. What, your DAW doesn't have a polarity button for each hardware send? Bummer!

I don't love the idea of shorting any active output, especially one that's kind of designed to provide relatively high current. A lot of those chips are going to be short-protected, but better safe than sorry. Just opening the hot connection should work just fine.

[floid]

I think the key sentence there is, "Flip the polarity anywhere in the signal chain." Same should apply to the channel mute. Somewhere in your DAW or interface control there's prolly a solution that takes only a few mouse clicks once you find it.
Very cool pair of ideas BTW. Makes me consider headphone bleed phase. Really need to find time to read the new issue.

[aquaman5k]

Perhaps I'm missing the point here, but why not just pan the entire mix in your daw to the side of the phones you want to monitor with? Solves the bleed from unused side problem.

[ashcat_lt]

I took that article to be more about the relative phase between what's in the headphones and either a vocalists own voice in their head or the acoustic sound from the room bleeding through the headphones. It makes a lot of sense, and I'm definitely trying it next time a situation like that comes up.

I guess I can see where you might like to have a little switch box there near wherever the headphones are in cases where that's not near the DAW, and you don't have anybody else running the thing so you can a/b in situ or whatever.

I find myself wondering, though, do you just run your headphone mix mono, then? I guess you do it all the time already, but IDK if I'd want to just throw away the one side of the mix.* A DPDT and two resistors instead of the SPST could have it sum both signals to the one side of the headphones. Wouldn't take much more space. The resistances would be pretty dependent on the particular model of headphones, though. There are orders of magnitude difference between the impedance of different models, so it would be tough to come up with anything close to decent compromise.

If we went active, then the whole thing gets a little easier. You'd basically be building another headphone amp, but I think it could be a single chip and a few resistors and caps. Even through hole parts could get close to the little wart I think you're wanting, but it would need external power. I know that's not what you're shooting for. Just kind of riffing.


* I personally can't work with one cup off. The whole idea kind of creeps me out. I'd much prefer to tweak the headphone mix till it works so that I can remain completely immersed in the mix while doing whatever I'm doing. I almost find myself wondering if that phase trick might be the difference that could stop someone wanting to uncover that one ear.

[Suntower]

But simply killing one or the other side of the phones with a switch isn't too tough. I'll put together a parts list and a recipe tonight or tomorrow.

Look forward to it!

TIA,

---JC

[Randyman...]

I think the key sentence there is, "Flip the polarity anywhere in the signal chain." Same should apply to the channel mute. Somewhere in your DAW or interface control there's prolly a solution that takes only a few mouse clicks once you find it.
Very cool pair of ideas BTW. Makes me consider headphone bleed phase. Really need to find time to read the new issue.

Yep - Just flip phase (polarity to be accurate ) in your DAW's monitoring path Since the vocals aren't generally part of any multi-mic setup, you could also flip phase at the mic-pre or input chain if needed.

If you are not the vocalist, then flip phase while the vocalist is monitoring themselves and let them decide which polarity they prefer. As mentioned - this has to do with the internal head sound the vocalist hears against the mic'd signal in the cans. No different from aligning a multi-mic setup on an instrument if you think about it (the 2nd "mic" is essentially the vocalists' internal head sound)

For the 1-ear thing and summing to mono: I personally use power amps to drive my cans (pair of Lectrosonics PA8's - will drive the living snot out of any cans!!!), so I'd recommend against summing L/R signals post headphone amp to avoid issues with the power/current section. I'm sure lesser HP outputs might handle this just fine (basically a beefed up line output for most pro-sumer devices).

Also as mentioned - I'd just sum to mono and pan to the desired earcup in the DAW - but a single SPST switch in a small project box with TRS in/out to kill one earcup would also be easy-peasy...

[Suntower]

Perhaps I'm missing the point here, but why not just pan the entire mix in your daw to the side of the phones you want to monitor with? Solves the bleed from unused side problem.

That's a great idea. Unfortunately, my headphone amp doesn't have a pan knob.

I use Cubase. I -can- pan the mix left/right but it's a pain. You have to do a bunch of mouse clicks. What I want is something INSTANT.

I'm recording me singing. Everybody is different, but when I have both earpieces on it REALLY affects the singing tone... and even worse, my sense of pitch. The pressure on the side of the head just changes -everything-. With one earpiece off, it feels like "Now my head can -breathe-."

So I want something I can enable/disable without touching the DAW and losing concentration. I've got enough to think about whilst tryng to sing.

Thanks!