25 meters XLR cable ?

[bbontempi]

hello

my drumkit is in my basement
my studio is on the first floor

i need a few XLR cables that are 25 meters long. i plan to make them, but have a few questions :

- will i hear any loss in quality ?
- should the cables be of a higher diameter / quality than a regular XLR cable ?
- does +48v phantom power manage to get this far without loss of voltage ?
- any other recommandations ?

and a bonus question : my AKG D112 dynamic mic got fed with +48v phantom power accidentally, i noticed that later after recording. but it worked, and the mic doesn't seem to have suffered from it.
phantom power is applied to both preamps of my soundcard (2 built in pres). you can't apply it to a single channel, which is annoying as i record my drumkit with two mics : an overhead (condenser mic which needs +48v) and the D112 (no PP needed).
does it mean i can send +48v to my D112 without damaging it ? would be quite handy...

thanks
bontempi

[vivaceserenade]

Here's my two cents:

XLR Cables are typically "Balanced", meaning you've got two conductors and a shield. They tend to do pretty well on long runs (snakes can be hundreds or meters). I would caution against making them yourself...Dop you have that much shielding? You might get a lot of noise.

As for your D112, typically phantom power doesn't damage dynamics...

[bbontempi]

thanks

i can't find 25 meters long cable. that's why i thought i would make em. i would use high quality cable and some good connecters. do you think i'll still get noise ?

otherwise i would get this
http://www.thomann.de/fr/cordial_ctm_20_fmsw.htm
and add one of my 6 meters XLR cable at the end of it.
does cumulating xlr cable reduce sound quality btw ?

[vivaceserenade]

I am from the states, so forgive my non-metric units
There are long enough xlr cables in production, but they are not cheap. You can easily find 50 ft (Say 15 meters). You could link them together. If you are going to need more than 3 25 meter sets I'd buy a snake...

[ghr]

Naah just learn to make them - its a good thing to know!

I'd use Neutrik XLR's since they're much easier to solder and much tougher in use.

I once bought a 100 meter roll of van damme installation cable from ebay for about £40 - have a look if you can find a similar deal. Its a bit thinner than your average mic cable but for running it down the basement it would be fine.

Good luck!
Gareth

[bbontempi]

thanks guyz !

snakes are cool but i can't find one that fit my needs : 6 XLR inputs, 20/25 meters ...

another one : when i'll buy a good external preamp, shall it be in the basement, or in my studio ? maybe it doesn't matter ?

[Aural Reject]

25m is not that long for an XLR-XLR cable.

Premade 20m cables are available from, e.g. Canford , 25m cables from Studiospares ......

They also sell snakes - or will make them to order - but it'd be more usual to find 8 way rather than 6 way . Plenty of other companies also do them - Van Damme will also do them both off the shelf or to your spec.

With respect to where you put your preamp, bear in mind that if you're going to put it in the recording room, it'll need to be a remote model. So for instance, if you want to track a drumkit with 8 preamps and you want them near the drummer you'd need something like an 8 channel iPre or an RME Micstasy - neither of which are cheap - whereas you could just get something like a lowly Audient ASP008 if you had the controls next to you

Horses for courses.

[grab]

Snakes commonly tend to be 15m or 30m, and usually have channels in multiples of 4. No reason why you can't get an 8-channel 30m snake - gives you a bit of spare cable to let you make the cable run neater, and a couple of spare channels for when things inevitably go wrong (or when you inevitably need that one one mic for the perfect sound).

Actually, checking Thomann they do have 6-way snakes. The longest is 15m, and two of them together will get you the distance you want for a grand total of £60, which looks like the cheapest option. Strangely, Thomann don't actually seem to have 8-way 30m snakes - next up is an 8/4 30m one at £140, or two 8-way 15m for £86.

[ghr]

If you want a snake, Studiospares do a 25m 8 channel snake on a drum for about £60. I did have a quick look on the website but the laptop I'm using was too slow so I didn't find it. The drum is yellow - you should be able to find it!

[Hugh Robjohns]

- will i hear any loss in quality ?

Provided the cable is good quality, no, you won't hear any difference. Again, provided the screening is good you won't suffer any more interference either. Don't get foil screen cables though -- they don't like being handled that much. Go for something with a lapped screen, preferably Reussen screened (double lapped).

- should the cables be of a higher diameter / quality than a regular XLR cable ?

No, but better quality is always good. Making up cables is easy enough -- it's only three wires per connector. Use Neutrik connectors -- eay to wire and fit, and very reliable.

- does +48v phantom power manage to get this far without loss of voltage ?

Yes. I've ran phantom powered mics at the end of many hundreds of metres of cable without problems before now. Don't worry abut it!

- any other recommandations ?

Good idea not to run long mic cables alongside long mains leads or anything carrying 'nasty' signals like lighting cables. But other than that, No.

and a bonus question : my AKG D112 dynamic mic got fed with +48v phantom power accidentally, i noticed that later after recording. but it worked, and the mic doesn't seem to have suffered from it.

It is designed to cope with phantom power without being upset in any way. That's the reason it's called phantom power. Only those mics that need it can see it's there. Other (balanced) mics can't see it at all -- it's like a ghostly apparition!

phantom power is applied to both preamps of my soundcard (2 built in pres). you can't apply it to a single channel, which is annoying as i record my drumkit with two mics : an overhead (condenser mic which needs +48v) and the D112 (no PP needed).

That's not unusual. Lots of budget consoles are configured to provide phantom on all inputs or none. Provided all the cables are balanced XLR types, and all the mics are balanced with XLR connectors, there won't be a problem.

does it mean i can send +48v to my D112 without damaging it ? would be quite handy...

Yes. Absolutely.

If you want to be a good two-shoes, you could turn off the phantom when plugging or unplugging the D112. Some people fret about hot-plugging dynamic mics. Personally, I never bother and I've been working wiotrh mics for longer than I care to remember. Never destroyed one with phantom power yet.

Hugh

[bbontempi]

thanks a lot !

[-Nightspirit]

hey Hugh.
some years ago I pluged a sennheiser vocal mic into the +48 phatom power of a mixer. suddely I could not sing into it any more... the mic was complitly dead.. all after that I am very carefull ot plugging a dyamic mic into phatom power...

[IvanSC]

since nobody mentioned it, I will. It wouldn`t hurt to get Starquad cable, which is both electrically and mechanically better able to cope with long runs in adverse conditions.

It`s a stock cable available off the shelf at StudioSpares Canford etc etc & is worth spedning a little more money on in the long run.

[Aural Reject]

Unless I was going to be at risk of possibly fairly major interference I wouldn't bother with starquad.

Putting my ridiculous memory hat on, 0VU answered a similar question at length back in 2004 in V2 here. ....note the reference to HF loss

[Steve Hill]

snakes are cool but i can't find one that fit my needs : 6 XLR inputs, 20/25 meters ...

For drums, one day you will need more than 6 lines. Trust me on this. And you also need to think about sending a headphone mix back to the live room.

Buy a decent snake... it will be cheaper than lots of long XLR cables (and tidier). I'd go for at least 12 or 16 lines including headphone return lines.

I'm not being extravagant with your money: I've binned snakes with too few lines in the past, when I realised I should have got it right in the first place!

[chris...]

It is designed to cope with phantom power without being upset in any way. That's the reason it's called phantom power. Only those mics that need it can see it's there. Other (balanced) mics can't see it at all -- it's like a ghostly apparition!.

Interesting - I'd always assumed it was called "phantom" due to not needing an extra wire, cunningly using the signal cable (without affecting the audio).

Live and learn

[Hugh Robjohns]

some years ago I pluged a sennheiser vocal mic into the +48 phatom power of a mixer. suddely I could not sing into it any more... the mic was complitly dead.. all after that I am very carefull ot plugging a dyamic mic into phatom power...

The only way that could happen was if the dynamic mic (or the cable being used) was wired in a weird way (very unlikely in the case of a sennheiser mic, but quite possible in the case of an XLR cable of unknown provenance)!

And even then, the fault would only remain while the phantom power was applied and the mic was used with the faulty wiring -- it is very unlikely to become permanent.

What can happen if the mic or cable is miswired is that the 48V phantom is applied across the dynamic mic's voice coil, forcing it to behave like a solonoid. The current flow through the coil forces it to move in one direction or the other to the endstops, tensioning hte diaphgram and thus makinng it almost completely insensitive to sound (sometimes you'll still get some HF end of the spectrum, but certainly no bass). Remove the phantom power (or fix the broken cable wiring), and everything returns to normal.

Very occasionally, and only in certain situations, a fault of this kind can permanently magnetise the moving coil element, which will have a long term affect on the sound quality. But this is very rare, and can be fixed by careful deguassing.

Hugh

[Hugh Robjohns]

Unless I was going to be at risk of possibly fairly major interference I wouldn't bother with starquad.

Me neither. None of my four multicores are star quad, and only one of my three cable drums carries starquad (and that's only because I needed a lot of cable in a hurry and I couldn't get my preferred cable in time, so I went with a known alternative safe option.

Star quad has its uses -- but they are restricted to the (few) occasions when a strong interference source is placed close (within millimetres) to the mic cable. Once you get that interfering source more than an inch or two away, starquad is no better at rejecting interference than any other decent balanced cable -- provided the screens are equally good in both types.

The downside is that while starquad might provide worthwhile interference rejection on the odd rare occasion, it loads the cable up with huge amounts of additional capacitance all the time. And in long cable runs that translates to a noticeable loss of HF response.

So personally, I run double-lapped (reussen) screened cables in all my multis and most single XLR cables, and take care to position them away from potential sources of interference (and/or cross potentially interfering mains or lighting cables etc at 90 degrees).

Never suffered interference during a recording in twenty odd years. I thought I had a problem a few months back -- mobile phone chirps breaking into one mic circuit. Turned out it was getting in through the mic, rather than the cable! And it was an extreme case with a moby phone in a handbag leaning right against the mic on a low floor stand.

Moving the handbag to the other side of the cellist's chair cured the problem. Changing the cable to starquad didn't!

Hugh

[chris...]

Moving the handbag to the other side of the cellist's chair cured the problem. Changing the cable to starquad didn't!

Hehe - yep that effect is always v. short range.

[Hugh Robjohns]

Interesting - I'd always assumed it was called "phantom" due to not needing an extra wire, cunningly using the signal cable (without affecting the audio).

Live and learn

It's a DC supply, so needs a positive and negative connection. The negative is on the screen, the positive is shared equally between the two balanced audio lines.

Regardless of whether the mic is dynamic or electrostatic, the signal is always sent as differentially on the two audio lines. The fact that they happen to be biased to +48V (reelative to ground) makes no difference to the audio circuitry. That voltage can't be seen because there is no ground reference involved in the audio signal.

The phantom power can only be 'seen' when referenced to the ground.

It's the ability to see it or not that lead to the term 'phantom' -- it's there, but you can't see it! Spooky.

Hugh

[bakup]

got my 30mt 12+4 from loudest.com came with xlr to jack adapters as well free best price i could find and more than pleased with the build quality, t4tea