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Can't hear anything!

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Can't hear anything!

Postby Murdoch » Thu Oct 06, 2011 9:40 pm

Only just tried my new SE4s and can't hear anything.

SE4 -> Peavy mixer via XLR. Mixer -> headphones.

All knobs and sliders where they should be. Phantom power switched on and I can't hear anything.

Tried my dynamic mic (without phantom) and I can perfectly.

Am I missing something here?
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Re: Can't hear anything!

Postby Rob Taylor » Fri Oct 07, 2011 1:06 am

If another mic works, then I'm going to say there's nothing wrong with the signal chain, and the problem lies with the mic. It's only logical.

Have you got any other system to try it on? Is everything with the mic as it should be (pads/attachments etc.)? When in doubt, check the manual, if they were supplied with one. It seems odd that both would be faulty, so just run through from source material to monitoring, checking everything thoroughly along the way.

If nothing works, come back with some more info (what mixer, what settings, what you are doing to set-up the mic through the desk, that kind of stuff).
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Re: Can't hear anything!

Postby ef37a » Fri Oct 07, 2011 6:25 am

Check for 48volts at the mic end of the XLR. Pin one is common then you should have ~ +48V on pins 2 and 3. No? Try another lead. Still No? Spook juice is not getting out of mixer, tech' job.

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Re: Can't hear anything!

Postby Mike Stranks » Fri Oct 07, 2011 7:53 am

Do you have access to another condenser mic? Does that work? (I presume you've tried BOTH SE4s.)
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Re: Can't hear anything!

Postby Hugh Robjohns » Fri Oct 07, 2011 10:41 am

If it works when you plug a dynamic mic into the cable, but not when using a capacitor mic, and you're sure you've turned on the phantom power, then clearly the signal path is wortking.

So the most likely possibilities are then either:

1). Broken screen connection in the cable. This would prevent phantom power from reaching the capacitor mic, but the signal from a dynamic mic would be unaffected.

Try swapping for a diffrent XLR-XLR cable -- and ideally one that you know works with phantom powered mics.

2). Phantom power not being generated in the PSU, or not of sufficient voltage to power the mic.

You'll need to test the phantom power voltage using a multi-meter or a 'bright-eyes' tester or similar.

3). Broken microphone -- check it out on someone else's system if you can to check that it really does work.

if I had to bet, my guess would be for option 2: insufficicent phantom power voltage because of your use of the words 'peavey mixer'

I've come across a few that, for reasons that I've never fully understood, seem to think that 15V is perfectly adequate for a phantom power supply. It isn't for the vast majority of capacitor mics.

As Dave says, check the phantom power voltage, or the handbook specifications. Which Peavey mixer is it?

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Re: Can't hear anything!

Postby Murdoch » Fri Oct 07, 2011 4:27 pm

Thanks for the feedback!

Ok, the manual reads "Applies 22 VDC voltage to the input XLR..." I take it this is the problem?
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Re: Can't hear anything!

Postby Hugh Robjohns » Fri Oct 07, 2011 5:15 pm

Oh yes!

Few mics will be happy with 22V of phantom power. Some mics are designed to cope with a wider range. Many AKG mics will happily tolerate anything from 9 to 52V, for example, and their handbooks state the fact.

But the vast majority of mics are designed to work on a nominal 48V phantom power, and the international phantom power standard -- P48 -- is specified very precisely to provide +48V DC +/-4V when off load. In other words it should be between 44 and 52V.

22V is definitely not a P48 supply.

I'd send the mixer back as being unfit for the intended application and get something designed by an intelligent company instead.... but if that's not possible, your only option is to buy an external phantom power unit such as
this one from ART pro

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Re: Can't hear anything!

Postby ef37a » Fri Oct 07, 2011 5:16 pm

Murdoch wrote:Thanks for the feedback!

Ok, the manual reads "Applies 22 VDC voltage to the input XLR..." I take it this is the problem?

What a load of wallies! Why can't they just do the bloddy job right! That said I suspect that there are vastly more cap' mics that will work on 22V than 15. I still bet you've got nowt.

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Re: Can't hear anything!

Postby Murdoch » Fri Oct 07, 2011 6:04 pm

Phew!

Any chance that me trying the SE4s on the mixer could have damaged the mics?

Oh I'm looking to get my hands on a RME 800 or MOTU 896 Mk3 soon, this is an old 6chan mixer bought a million years ago or so. Cant wait to see the back of it

Thanks again guys.

Would also appreciate your thoughts on RME Fireface 800 or MOTU 896 Mk3.
http://www.soundonsound.com/forum/showf ... t=1#945911
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Re: Can't hear anything!

Postby Mike Stranks » Sat Oct 08, 2011 10:27 am

Would that we could always assume that when we see "Phantom Power" on a product it always means 48v...

I've been investigating this a bit recently (nothing to do with this post) and have discovered that, particularly at the "shallow end", all is not what it at first appears. There are several mic preamps and mixers that state in their blurb that they provide Phantom Power, and it's only when you dig a lttle deeper that you discover it's not necessarily 48v phantom.

It can get confusing as some mic manufacturers state that their mics will operate on 24v or 48v phantom power. Rode is the example that springs to mind; their on-line specs are good in that they state unequivocally on what phantom each mic will operate to spec. So if you get the right mic/preamp/mixer combination the non-standard phantom may not affect you at all!

Let the buyer beware!
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Re: Can't hear anything!

Postby John Willett » Sat Oct 08, 2011 10:40 am

ef37a wrote: I suspect that there are vastly more cap' mics that will work on 22V than 15. I still bet you've got nowt.

I doubt it.

Most mics are 48V ±4V (IE: 44-52V)

Others are normally 9-52V (or 12-48V ±4V) so the number of mics that will work with 15V would be about the same as those at 22V.

It is interesting to note that neither 15V nor 22V is an official phantom voltage. The official voltage is 48V, with 24V and 12V being added to the spec. later.
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Re: Can't hear anything!

Postby ef37a » Sat Oct 08, 2011 11:40 am

Not always the whale poo end at fault Mike!
My now unused Behringer X802 gave ~47V iirc as did the long defunct BCA2000. The fast track pro is also on the spooky money.

My ESI 1010e on the other hand blatantly says on the front panel "2xXLR with Phantom Power(+48V)"
Bloody not! It is +12 unless you connect a (not supplied) 12V 1A rat. This is of no consequence to me since, 1) my AKG P150's are quite happy on 12V (might compromise ultimate headroom but things never get that loud at chez Dave!) and 2)Finding DC of almost any voltage and current delivery is not a problem! But as Hugh says, many mics will not be happy or not work at all.

But can I make the observation that I have read countless reviews of Mackie products in SoS and I cannot ever remember the non-standard phantom voltage being mentioned? Twas news to me....Would it really be SO much trouble to pop in an XLR loaded with resistors and check the PPwr at say 7mA (=24V) into mixer, AI and pre amp inputs?

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Re: Can't hear anything!

Postby Hugh Robjohns » Sun Oct 09, 2011 4:03 pm

Murdoch wrote:Any chance that me trying the SE4s on the mixer could have damaged the mics?

No, that's extremely unlikely. I'm sure they'll be fine when they see a proper +48V phantom supply!

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Re: Can't hear anything!

Postby Hugh Robjohns » Sun Oct 09, 2011 4:16 pm

ef37a wrote:Would it really be SO much trouble to pop in an XLR loaded with resistors and check the PPwr at say 7mA (=24V) into mixer, AI and pre amp inputs?

I can't speak for other reviewers, but I also do precisely this kind of test when the unit is on the bench... and all other reviewers will check with typical end-user mics and would comment if they found problems.

It is pretty rare that equipment doesn't deliver a sensible phantom supply, although it's not that unusual to find the supply rail sagging on mixers if there are sevreal thirsty mics plugged in!

As it happens, I've just had to send a review product back and have it replaced with another sample partly because it did actually fail the phantom power supply test. It turned out it was from a first production batch that were found to have a number of other issues too... and all bar two of these units (one being the dealer's sample that was sent to use for review) had already been recalled and upgraded at the time I was doing the review!

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Re: Can't hear anything!

Postby ef37a » Sun Oct 09, 2011 4:50 pm

Sorry Hugh!

I did not know you did that. But then you rarely get to review products at the "shallow end" as Mike put it!

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Re: Can't hear anything!

Postby twotoedsloth » Mon Oct 10, 2011 11:31 pm

SOS reviewer Dan Worrall really dropped the ball when testing the Mackie Satellite. The unit does not supply 48v phantom power, even though the damned button on the front of the unit says "48v". It gives between 42 and 43 volts, which is probably fine for most microphones, but I'm not really confident about trusting a box that doesn't do what it says. I can only use it as a firewire D to A converter (a job which it does do well, to my ears).

Even more frustrating, I contacted Mackie and their tech support told me to purchase a new power supply, which I did (for $40 plus shipping), and it confirmed the problem, only 42 to 43 volts. Another tech acknowledged this "design compromise" so that the Satellite could be bus powered. And they wouldn't take the power supply back and refund my money.

I know, buyer beware, but readers like me do rely on reviews when it comes to researching which products to purchase.
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Re: Can't hear anything!

Postby ef37a » Tue Oct 11, 2011 5:58 am

I agree Twotoedsloth, "buyer beware" but how can we be so when, as you say, equipment is marked porkified, your Mackie and my ESI. In the case of the latter yes, the 12V supply IS mentioned in the handbook but they then go on to give the grossly erroneous information that "Most capacitor microphones are quite happy on 12volts" ! And why should "bus power" be a problem? My Fast track pro chucks out 48V and that is puny usb. Firewire is 12volts and a higher overall current capabilty.

Another figure that I wish manufacturers and reviewers alike would give is a practical mic sensitivity. "55dB" for max gain means diddly. What we need is an input figure at max gain in millivolts for say, -18dBFS. I don't expect a fullblown noise, distortion,response test in a 1/2 page review of a £100ish AI or pre amp but Ppower and "will it work with a '57" should told and should not take very long (only 2 inputs at this price) once the kit to do it is built. It seems the magazine is frightened of a standard format, boring or something? So put the info in a boxout.

I will no doubt be accused of yearning for earlier times and styles? You betcha!

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Re: Can't hear anything!

Postby Hugh Robjohns » Tue Oct 11, 2011 10:50 am

twotoedsloth wrote:The unit does not supply 48v phantom power, even though the damned button on the front of the unit says "48v". It gives between 42 and 43 volts, which is probably fine for most microphones, but I'm not really confident about trusting a box that doesn't do what it says. I can only use it as a firewire D to A converter (a job which it does do well, to my ears).

Don't know how you measured this. All phantom supplies will only appear to be 48V if you measure with no load (ie, a very high impedance voltmeter). As soon as any current starts to flow the 6k8 feed resistors will produce a voltage drop. Less than 1mA current draw will produce a 6 volt drop, for example! Added to which, the phantom standard allows a 4 volt tolerance anyway -- the raw phantom supply can be anything from 44 to 52V quite legitimately.

I know, buyer beware, but readers like me do rely on reviews when it comes to researching which products to purchase.

Detailed technical assessments of products require trained and experienced technicians or engineers, with suitable test equipment and the ability to use it properly... and who can write coherently... and such people are pretty rare. So while I am sufficiently anal as to check the phantom power voltage, few others would.

What they would do, though, is plug some mics in and see if it all works as intended. And I presume in this case that it did. Indeed, I would be surprised if you noticed any issues with a phantom supply producing 43V unless you are working with extremely current-hungry mics or recording very loud sources at very close range.

I understand your concerns and share your frustration that some manufacturers cut corners in this way. But that is the nature of budget equipment, sadly, and 95% of the time they get away with it because, actually, it isn't that critical in most situations.

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Re: Can't hear anything!

Postby ef37a » Tue Oct 11, 2011 7:20 pm

Well I find it a bit sad Hugh that few of the reviewers at SoS can wield a DVM! As for the source R leading to errors, even an old rougharse Avo 7 at 10k per volt would only give about 0.4volt error on the 100V range and as you say, phantom power has a buslane tolerance.

You did not comment about my point on mic sensitivity. A bit more technical to measure I agree but a noise source could be used to squirt in say 100microvolts and the level given in the DAW? The AI makers cannot argue* the figure since almost none of the buggers ever publish it and despite great efforts on my part on one occaision (Alesis) they won't tell thee!

*As used to happen in days of yore, manufacturers would take technical issue with a review figure of specification and a gentlemanly (and very entertaining!) ding-dong would ensue, often over several months!....Perhaps this is what you are worried about? If so, shame. A good spat in the mags is sadly missing these days!


"Budget" equipment it may be but very good, very accurate testing kit has never been cheaper for manufacturers to have and keep calibrated. We deserve that at least I think?

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Re: Can't hear anything!

Postby Murdoch » Wed Oct 12, 2011 11:33 am

Ok, so my Focusrite Pro 40 came today

Do I need to connect to computer to hear anything? Because I plugged it in, plugged in SE4 and switched on 48v Phantom and no sound Surely its not entirely dependent on a PC? I have yet to order an ExpressCard FireWire adapter.

Also there is no manual, am I supposed to get a manual with this?
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Re: Can't hear anything!

Postby ef37a » Wed Oct 12, 2011 11:57 am


`You would think you would get a printed manual with a £400 bit of kit but probably not! Be a .pdf on the disc or do as I have just done and download it.

That tells me that the unit will work "stand alone" but needs to be configured on the pc first.

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Re: Can't hear anything!

Postby . . . Delete This User . . . » Wed Oct 12, 2011 11:58 am

manual is on the driver disc for the computer.

(not sure if they ship a paper manual , but i suspect not)


it's an audio interface.... so much functionality IS dependent on connection to a computer, however it DOES operate in a standalone mode.... but it may have to be connected to a computer to set it up the way you want it.... as it has a couple of options....


http://www.focusrite.com/download/940/User_Guide_Saffire_PRO_Standalone.pdf

http://www.focusrite.com/download/614/PRO40-UserGuide-English.pdf
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Re: Can't hear anything!

Postby Murdoch » Wed Oct 12, 2011 12:45 pm

ef37a wrote:
`You would think you would get a printed manual with a £400 bit of kit but probably not! Be a .pdf on the disc or do as I have just done and download it.

That tells me that the unit will work "stand alone" but needs to be configured on the pc first.

Dave.
Or even better... wait for it... no installer disk

They've supplied unwanted CDs of BassStation, Live Lite 8, etc. But no installer/driver for me to actually work my £400 piece of gear.

Off duty BBQ lighter AKA Idris wrote:manual is on the driver disc for the computer.

(not sure if they ship a paper manual , but i suspect not)


it's an audio interface.... so much functionality IS dependent on connection to a computer, however it DOES operate in a standalone mode.... but it may have to be connected to a computer to set it up the way you want it.... as it has a couple of options....


http://www.focusrite.com/download/940/User_Guide_Saffire_PRO_Standalone.pdf

http://www.focusrite.com/download/614/PRO40-UserGuide-English.pdf
Thank you! Shall follow through soon as I get my hands on the driver, which their website doesn't have for some reason.

Does anyone have the driver I can borrow please?
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Re: Can't hear anything!

Postby Murdoch » Wed Oct 12, 2011 1:12 pm

Already installed the Saffire Mix Control 2.4, which doesn't seem to be the installer/driver. As paper supplied with box reads "Double Click 'Install Saffire PRO40'" an icon not found on any CD supplied. Also installed everything supplied and hardware still not found

Got in touch with Focusrite, awaiting reply.

Oh and my computer in my room had FireWire
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Re: Can't hear anything!

Postby ef37a » Wed Oct 12, 2011 1:24 pm

Actually you know these AI manufacturers really want a good telling off about not supplying a manual!

You can go to Sainsburies and pay £199 for a Freeview HDD recorder and you get a nice chunky book. The AI people KNOW we are all cute enough to run a .pdf or download the bumpf so they let us use OUR paper and OUR toner to get a hard copy.

Found yet another thing for reviewers to do Hugh! Moan like a drain when you don't get a good book!

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Re: Can't hear anything!

Postby Murdoch » Wed Oct 12, 2011 1:29 pm

ef37a wrote:Actually you know these AI manufacturers really want a good telling off about not supplying a manual!

You can go to Sainsburies and pay £199 for a Freeview HDD recorder and you get a nice chunky book. The AI people KNOW we are all cute enough to run a .pdf or download the bumpf so they let us use OUR paper and OUR toner to get a hard copy.

Found yet another thing for reviewers to do Hugh! Moan like a drain when you don't get a good book!

Dave.
I second this. Or having to pay extra for a bag for your delicate headphones that cost £140.
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Re: Can't hear anything!

Postby Murdoch » Wed Oct 12, 2011 3:07 pm

Managed to get it to work. Don't know how. The Mixer wouldn't load before, saying no hardware connected, etc. Rebooted several times and it loaded, had it running standalone.
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Re: Can't hear anything!

Postby Hugh Robjohns » Wed Oct 12, 2011 3:33 pm

ef37a wrote:Well I find it a bit sad Hugh that few of the reviewers at SoS can wield a DVM!

I doubt most know what a DVM is... and why should they? The majority of our reviewers are musicians, not technicians. Each discipline brings it's own viewpoint to the party, but whereas tech-heads like you and me are interested in the technicalities, probably 90% of our readership just isn't. Obviously, I'd be hugely disappointed if a reviewer didn't make use of all the facilities of a product to check they all work adequately, but I'm not surprised that no one noticed a slightly low phantom power voltage in a practical test.

You did not comment about my point on mic sensitivity.

That's because it wasn't there when I was responding. I'm not sure I really understand your point. Surely, all that's needed is to know the amount of preamp gain available? 80dB would be plenty for anything. 60dB covers almost everything, and 40dB isn't really enough unless you're close-miking loud sources. Obviously it would be possible to contrive a reference level noise source and state the digital output level for a given gain setting but what help would that really be. Who really knows what output level they get from their mics and how that would relate to your 100mV reference?

There are too many variables here. Mic sensitivity can vary from 1mV/Pa for a quiet dynamic up to 35mV/Pa for a loud capacitor mic. That's a 30dB range right there. Then there's the inverse square law to deal with when placing the mic at differing distances from the source, and the loudness of the source itself. The combination easily adds another 30dB range to deal with. So depending on the nature of the source, the type of mic and where it's placed you might need just a few dB of gain or a full 70dB to get the same output level...

*As used to happen in days of yore, manufacturers would take technical issue with a review figure of specification and a gentlemanly (and very entertaining!) ding-dong would ensue, often over several months!....Perhaps this is what you are worried about?

Definitely not something we're worried about, but we don't tend to go in for detailed technical spec checking anyway. There's not much point and very little interest as pretty much everything measures stunningly well anyway. Moreover, there are very, very few reviewers who are 'technically qualified' and experienced enough to undertake that kind of work, with appropriate test equipment anyway. To be blunt, the SOS market really isn't interested in technical specs, largely becuase they have no need to be, but also because most don't have the background technical knowledge to understand them anyway.

Sure, there was a time when equipment could be differentiated on tech specs alone, and in those days detailed technical reviews were an source of critical, independent buying information. That really hasn't been the case for decades. Noise, distortion and bandwidth are almost always superb these days. People buy on features and facilities these days, not tech specs.

Having said that, because of my background and interests I do routinely check the specs, and it's not unusual to find minor discrepancies between claims and measurements. But often that's just down to small differences in the way things can be measured or the equipment used -- and who cares if a manufacturer claims -1dB at 40kHz and I measure it to be -1dB at 38kHz?

Of course, where there is a significant difference between claim and measurement I will query it with the manufacturer and comment upon in the review if it's appropriate. SOS has never been shy of stating a genuine negative opinion provided it can be backed up.

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Re: Can't hear anything!

Postby Hugh Robjohns » Wed Oct 12, 2011 3:36 pm

ef37a wrote:Found yet another thing for reviewers to do Hugh! Moan like a drain when you don't get a good book!

Perhaps you should try reading the magazine occasionally Dave! Our reviewers often comment on missing, poor or good handbooks.

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