Electric piano into mixer

[DoctorStar]

Dear all,

 

At the last school concert we had trouble getting good sound through the PA from the Clavinova style electric piano. Too loud, distorted, meh! Now we are doing another concert in a few weeks and I want a fix.

 

Here's what we had:

 

Piano --> TRS aux out (L/L+R) to XLR --> XLR to snake --> snake to mixer into a mic strip.

 

Now I think I've sussed (Googled!) the problem but want some affirmation so that I am not going to be chasing ghosts during the set up. I am guessing the signal from the piano is way too hot for a mic input and I need to chop it somewhere in the signal chain.

 

Would the insertion of a DI box between piano and snake solve the problem or have I misunderstood their purpose?

 

Kind regards,

 

DrS

[bruce]

Yes, a DI would sort it.

[J Pearce]

You're spot on, a DI box is exactly what you need.

 

 

It will offer attenuation to drop the level down to mic level, it will create a balanced signal - helping to eliminate hum and noise issues, and will correctly balance the impedance - which may improve frequency response over a long cable and may assist the performance of the mic preamp.

[Jivemaster]

DI boxes will convert an unbalanced signal to balanced, several offer some attenuation also. It's the attenuation that you may well need. The only way of checking is to do some tests in advance.

 

Alternatively make up a small attenuator, even a small resistor array inside a connector.

[Alec]

Piano --> TRS aux out (L/L+R) to XLR --> XLR to snake --> snake to mixer into a mic strip.

Are you *sure* it's a TRS (balanced) output on the keyboard? I'm not convinced, from the limited info I could find from some Yamaha manuals.

 

A hot output alone shouldn't be overdriving a mic pre-amp if you have the gain set correctly.

 

As others have said, a DI box will do the job properly, and is the correct approach to use.

 

Most importantly, though, and as Jivemaster said, test everything out in advance, rather than on show day - that way you will be confident that you have a working solution.

[Jivemaster]

Do try to read the manual for the piano. It's possible that the output you have is actually wired as a stereo jack, sleeve for common ground and L&R on ring and sleeve one way round. If your mixer is expecting a mic input (about 5mv ) having about 2 - 5 volts inserted isn't going to sound good. If your TRS jack is just one of two headphone sockets the level at the mixer will change if/when the performer turns up the phones.

[sandall]

To add to that - if there is only 1 jack socket (apart from any sustain / foot-pedal sockets) then it is definitely stereo out, probably at headphone level, so you either need to combine the L & R signals, using a fairly small value resistor in 1 leg (DON'T just short them together - it might be ok, but it might cause distortion, or even damage the piano), or get a stereo to 2x mono jack adaptor & use 2 DI boxes. On the other hand, if there are 2 jack Output sockets, 1 of them will be labelled "(Mono)", so unless you need the piano music to be stereo just use that one.

 

If you have your own passive DI box & can use a soldering iron I would suggest removing the wire link between the In & Loop Out jack sockets, & replacing it with a resistor of 100 - 470 Ohms (the value isn't critical, as it's much more than the output impedance of the piano & much less than the input impedance of the DI box). In theory you need 2 equal value resistors (1 for each leg), but in practise using only 1 resistor merely reduces either L or R by a very small amount.

[paulears]

Some Clavinovas ONLY have a stereo headphone output - no line level at all. If there are two, and one is crosswired to add left to right for mono only, then the DI will sort it. To be fair, an insert cable will do the same job if yours turns out not to have line outs.

[Jivemaster]

Searching for "Yamaha Clavinova user manual" gives several hits for whole ranges of user manual according to model number. Please check with your user manual, or an online one, which output connector arrangement is used on your Clavinova. Then you can determine what lead is needed to sum the output to mono and match the available output level to the input range of the mixer that you have. Once the clavinova is on stage it's effectively a point source to the audience so it's own stereo is irrelevant, If necessary it's output free of distortion can be fed to a panned position in the PA mix. Getting that output distortion free is the issue here, this can be solved once you/we know what the output connector and level is.

 

One clavinova manual (picked at random) suggested that 20w of audio was available, a 20w signal will overload most things and cause distortion in the PA system.

[timsabre]

In the first post he says L/L+R output. This will be a line level output which is automatically a mono sum if only one channel is connected. So the correct advice of using a DI has already been given.

[Brian]

As Tim says, it's two mono jacks with unbalanced audio. Plug into just the L/L+R and you get a mono mix...

 

[sunray]

If it is the Yamaha (as opposed to a general 'style' of instrument) which has 'L/L+R' & 'R' sockets. In my experience these are unbalanced stereo outputs or mono from the 'L', I have found they are quite a high O/P voltage, especially when running mono and usually run them into a 4:1 isolating transformer (10KR:600R) into the balanced LINE I/P of the desk and then run only a little on the gain pot if any.

 

A D| box is also a successful way to do the same thing.

 

Ah I hadn't seen the other replies. Brian is that the real circuit for the instrument or a generic? When is the relay released to silence the O/P?

[Brian]

That is snipped from a Yamaha schematic. I can't check which one as it is on my PC back in the UK and I am on my phone in Belgium.

[sunray]

Thanks Brian

[DoctorStar]

Well thank you all for your responses. Armed with a DI box, a few patch cables, a mixer and my handily in situ Fender amp, I spent a most pleasurable hour after school working out what goes where.

 

As suggested in the thread the Yamaha aux outs are quite hot but the DI did a good job of taming it and allowed a bit of gain structuring on the mixer.

 

Handily, the headphone socket can be used alongside the aux so I am going to use the headphone jack to feed a powered monitor speaker whilst the aux sends to the desk. Need to get a good whack for the piano monitor but for no one else.

 

All I need to do is tape over the master volume on the keyboard as this seems to carry out its role whenever and wherever......there seems to be no scenario this volume wheel isn't prepared to drive all over.

 

Thank you all,

 

DrS