Outputs on the keyboard are Line level not instrument level.

I would try plugging the L+R out into the instrument input of the Lexicon. Turn the volume on the P155 to about half. Turn the volume on Line 1 on the Lexicon all the way down. Turn on the demo program on the P155 and then turn the Line 1 volume on the Lexicon up until the yellow level indicator on the Lexicon flashes occasionally. If that doesn't happen until the level on the Lex is a 8 or higher, turn the Lex down, turn the P155 volume to 3/4 and repeat. If the Lex starts hitting the yellow at notch 1 or 2 - turn it down, turn the P155 down to 1/4 and repeat. This called adjusting the gain structure of your system.

Thanks Bob, I'll give that a shot tonight!

I can't tell from Yamaha's product spec list if the outputs are unbalanced or balanced, but if you haven't already, you may also want to try balanced 1/4" cables. There might be a better S/N ratio doing this.

Also, make sure you use BOTH output channels, some older devices skimp in the grounding & output schemes, making a single channel (esp the Right-out only) potentially very noisy.

Otherwise, follow Bob's excellent advice, and you should be in good shape.

JoeH - thanks for the advice! I was trying the only type of cable I have, a Dimarzio instrument cable.....not the right thing?

Also, I'm not sure what kind of cable I would need to be able to use both L and R outputs on the keyboard on one side, and the one instrument jack on the Lambda on the other.

But I should be able to successfully record the keyboard's sound, right? In the manual, it says MIDI and USB are the only ways to connect to a computer....

Gibbler
You should not use the instrument input on the front of the Lexicon....that would be for guitar or bass.
The input you want to use for keyboards are the line in inputs on the back
you can plug in either 1/4" TRS balanced or 1/4" TS unbalanced.
You can use your guitar cable if you like which is 1/4' TS unbalanced.
If you want stereo from the piano I would use two cables 1/4" TS unbalanced and use L and R out form the piano...the Lexicon won't care if its balanced or unbalanced but your problem is the piano looks like it only has unbalanced outputs.
If you continued to use that single instrument input on the front that is meant to be used for guitars etc.....you could damage the input instrument preamp on the Lexicon...at the very least you will overdrive it but I think those have protection....

dj - Thank you! Very good to know.....I'll stop using the instrument input and use the line inputs in the back.

While you should definitely try the line inputs in the back, I've had better luck with my Yamaha pianos through some sort of DI or the instrument input of a preamp or interface. You definitely need to watch the level of the keyboard output, but I haven't had a problem with the keyboard at half volume as I suggested. As is the case in the Lexicon, instrument inputs usually have a much higher input impedance. I assume that's why I usually like the sound better though an instrument input or DI. Again, the output should be enough to work with the line inputs, but I've always thought the sound was relatively anemic.

Hi. I have a similar situation to gibbler except for the Lexicon Lambda USB Interface. I have a Yamaha P-155 Keyboard and an Apple MacBook Pro. I need to record the digital piano in Garageband but I want to record the actual keyboard sound and not one of Garageband's software instruments. I was thinking of buying a MIDI to USB Adaptor and connecting the keyboard's MIDI IN/OUT to the computer's USB. I gather from gibbler's post that this wouldn't work to get the actual keyboard's sound into the computer. Having said this, what exactly do I need to buy? Should I buy something like a Lexicon Alpha USB Audio Interface or an M-Audio MobilePre and connect the keyboard's LINE OUT outputs to these boxes LINE IN inputs? Is there a cheaper alternative?
Any help on this is appreciated. Thanks.

I had a Tascam US-122 (since replaced in Tascam's lineup by the US-144 I think), but that started to get flaky at its old age of ~4yrs and I have since switched to a new PreSonus Audiobox USB. These are about as inexpensive as you can get when it comes to audio interfaces ($149 IIRC). If you do get one of these, you might want to try simultaneously recording the analog output from the keyboard as well as the MIDI data. Then you could compare various piano synths in Garageband against the keyboard's own synthesizer and pick whichever one sounds best.

Yamaha P155 - Midi Data - Sounds Different

At this time I still haven't tried recording the Yamaha P155's sound through it's AUX OUT ports to the computer but I have been able to save the midi data to a USB storage device and to transfer songs this way to the computer. The sound however seems very different in the computer although the data was recorded in the keyboard. I thought it would sound similar.

I am a newbie at this so I wonder if it's my ears or if in fact when you save a midi data file the sound is then "re-interpreted" by the computer instead of sounding exactly the same as when you played the music on the musical keyboard.

Can someone clear this up for me? I was trying to find a cheaper solution to buying a USB recording box but I guess a USB storage device isn't really an alternative?

Thank you.

I would definately run a stereo signal out of your keyboard into the stereo inputs on your Lex interface. With the stereo out/ins, noise should be minimal. Just remember to run a strong signal from the keyboard. If you run a weak keyboard signal, then try to boost it with the interface gain, you'll raise the noise floor significantly.

Good luck!!

brunob, post: 353991 wrote: I am a newbie at this so I wonder if it's my ears or if in fact when you save a midi data file the sound is then "re-interpreted" by the computer instead of sounding exactly the same as when you played the music on the musical keyboard.

You are quite correct. The information in a MIDI file is stuff like "middle C pressed with velocity X at time Y" and "middle C released at time Z". It's up to the playback device to generate the sounds you hear from this information. Therefore, 2 different devices can give you very different sounds given the same MIDI file.