SoundCraft Spirit M4 Problem

Posted: Sun Nov 04, 2007 9:31 pm

I recently purchased a SoundCraft Spirit M4 off of ebay so that I might simultaneously monitor my computer audio (M-Audio Delta 1010) and a digital piano (Kawai MP8) with a pair of Sennheiser HD595's.

The digital piano however when routed through the mixer sounds terrible. It becomes vague and muddied as opposed to the pianos onboard headphone output which sounds great. This despite trying every 1/4" and RCA input the mixer has to offer and adjusting EQ's accordingly.

As an example. the rhodes voice on the piano does this stereo phasing thing where the audio shifts quickly between the L and R channels giving this neat wavering effect but which is barely noticeable when routed through the mixer.

Has anyone suggestions?

Regards.

Posted: Sun Nov 04, 2007 9:36 pm

When you monitor the computer's output does it sound vague and muddy as well?

I'd expect that if you plugged the headphone output into a Spirit's channel that it would distort like mad!

Posted: Sun Nov 04, 2007 11:59 pm

As far as the Kawai is concerned, what output are you using to feed the mixer?
Are you using (2) mono input channels or (1) stereo input channel on the mixer for the Kawai?
When you are using the phones to monitor the mixer, what busses on the mixer are you using?
What you're describing sounds like a phase issue. Something like taking the stereo feed from the Kawai using the wrong jacks (like the headphone outs), and then routing the signal in such a way that it's being combined to mono before the headphone amp in the mixer gets it.

Posted: Tue Nov 06, 2007 1:02 pm

Take the problem step by step:

You should be plugging out of the Kawai's Left/Mono and Right 1/4" outputs and into the Spirit's 1/4" Line Inputs.
Keep the EQ on the Spirit zeroed out (all knobs centered, for now).
Hold a note on the Kawai with it's volume at a few notches under max.
PFL each channel (one at a time) that you have the Kawai plugged into.
Turn the pre-amps on the Spirit up (one at a time) until the Kawai's output is at Unity.
If you are plugging the Kawai into ch. 1 and 2, pan 1 hard left and 2 hard right.
Bring the faders on ch. 1 and 2 up to unity.
Plug your headphones into the Spirit if you haven't already.
Bring the Master Fader up to unity.
Slowly turn up the headphone gain pot until the Kawai is at a comfortable level.

Does it still sound funky?

Posted: Tue Nov 20, 2007 4:05 pm

Thanks for your quick replies and my apologies for, in comparison, the long time it has taken for me to get back to this topic.

I decided to take a stab at the process of elimination and provide those of you diagnosing with some additional insight. Note that I had only the following junk at hand with which to do so:

Gold-Plated Y-Adapter, Stereo Phone Jack to Phono plugs
http://www.radioshack.com/product/index.jsp?productId=2103713

Monster Cable Ultra Series THX® 600
http://www.crutchfield.com/S-qQzqxo14O2W/App/Product/Item/Main.aspx?i=119ULTI6H8

Gold-Plated Phono-to-Mono Adapter
http://www.radioshack.com/product/index.jsp?productId=2103711

Phone Plug Coupler (To allow monitoring w/ headphones)
http://www.radioshack.com/product/index.jsp?productId=2103722

*Note: If this configuration of cables/adaptors is to account for the troubles I am incurring, I am unsure how, and would appreciate your bringing it to my attention.

But in the mean time...

Directly monitoring the pianos L/Mono + Right outputs w/ a pair of HD595's via the necessary configuration of the aforementioned adaptors, results in a replication of the pianos on-board phones output. Allthough the L/
Mono + Right output is lacking in volume, it is however, with great definition, sounding good and clear.

When the above route is bypassed and the two adaptorized 1/4" TS cables are sent from the pianos L/Mono and Right outputs to the mixers STE1 inputs (download picture of mixers layout below and zoom in) the sound is then muffled and seems to loose stereo phasing and reverb/whatever effects the keyboard applies to its samples. This is especially noticeable on the pianos Rhodes sample which has the effect of incessantly phasing between the L & R channels as mentioned in my original post.

I also discovered that with the Rhodes sample if one of either two cables was removed from the mixer, and the other left inserted, the phase effect would immediately be heard. Once the removed cable was reinserted the phase affect was gone just as fast. I thought it strange that doing this only affected the Rhodes sample. With the main piano sample you could unplug either cable and notice absolutely no difference in sound.

Anyways, I then attempted outputting the pianos L/Mono and Right outputs to the mixers remaining 2nd, 3rd and 4th STE inputs in addition to its four Line inputs in which none of the inputs resulted in any difference in quality.

With that, I attempted monitoring the mixers L&R 1/4" Monitor outputs and could hear no difference in quality as compared to the mixers Phones output which was used until now.

Lastly, I outputted the pianos Phones output to each of the mixers aforementioned inputs, STE 1:4 and Line1:4 through which no differences in quality were detected.

Those of you with experience would be greatly appreciated should you place these facts in perspective.

Regards.

http://www.soundcraft.com/download.asp?filename=images/products/product_sheet/spirit_m_series/m4_hires.jpg[/quote]

Posted: Tue Nov 20, 2007 4:09 pm

bent wrote:

When you monitor the computer's output does it sound vague and muddy as well?

Nope, not at all. Sounds perfect.

bent wrote:

I'd expect that if you plugged the headphone output into a Spirit's channel that it would distort like mad!

Not so much/ Plugging the Kawai's headphone output @ full volume into the Spirit, as described in my second post, had barely enough 'juice', only when slamming on the keys, to clip/distort the Spirit.

Posted: Tue Nov 20, 2007 4:16 pm

Plug one 1/4" cable out of the Kawai L/Mono output into Stereo1 (L).
Plug one 1/4" cable out of the Kawai Right output into Stereo1 (R).

Set gain to unity while PFL is engaged.

That's all, it should work fine.

Posted: Tue Nov 20, 2007 4:20 pm

Quote:

Directly monitoring the pianos L/Mono + Right outputs w/ a pair of HD595's via the necessary configuration of the aforementioned adaptors, results in a replication of the pianos on-board phones output. Allthough the L/
Mono + Right output is lacking in volume, it is however, with great definition, sounding good and clear

When you do this you are listening to an un-amplified line level output, hence the lower level signal.

Posted: Tue Nov 20, 2007 4:24 pm

bent wrote:

Quote:

Directly monitoring the pianos L/Mono + Right outputs w/ a pair of HD595's via the necessary configuration of the aforementioned adaptors, results in a replication of the pianos on-board phones output. Allthough the L/
Mono + Right output is lacking in volume, it is however, with great definition, sounding good and clear

When you do this you are listening to an un-amplified line level output, hence the lower level signal.

That is correct. I am monitoring the L/Mono + R outputs directly to the headphones.

Posted: Tue Nov 20, 2007 4:30 pm

Im going to try and make a recording since I have a Delta 1010 interface installed. Will download one of those recording apps real quick and try to figure it out.

Edit: cakewalk'll be about an hour and a half.
Edit: screw that. trial version will be 5 minutes.

Posted: Tue Nov 20, 2007 6:59 pm

Dk,

I answered your PM and posted a pic for you, as you requested.

You shouldn't need any of those adapters you posted pics of, you are really going overboard there.
Like I said, just use two separate 1/4" cables - out of the Kawai's L/R outputs and into the Soundcraft's L/R stereo channel inputs.
They are line level inputs intended for just such a purpose.

Posted: Wed Nov 21, 2007 11:46 pm

bent wrote:

I answered your PM and posted a pic for you, as you requested.

Thanks.

bent wrote:

You shouldn't need any of those adapters you posted pics of, you are really going overboard there.

Agreed, but as explained in my second post, it is all I had available without the expenditure of dollars.

Anyways, I did everything as you instructed and I'm still loosing alot of quality routing the piano through this mixer.
I'm thinking that since this unit was purchased not only used, but on eBay, and worse over, from Canada, that the mixer is either defective or my Piano has some deep seated dislike for it.

Regardless, I appreciate the time and effort you have provided.

If you have a PayPal account, let me know. I'll gladly donate.

Regards.

Posted: Thu Nov 22, 2007 6:15 pm

If you agree that you do not need those adapters, why were you using them? You are not clear as to how you have this thing hooked up.

If you are connecting an RCA output to a TRS or TS input on the Soundcraft, you will have an impedence mismatch. It is not by much, but it is one nonetheless. This could be your problem. Connect RCAs to RCAs and TRS to TRS. Do not mic and match without an impedence matching transformer.

You can't connect the headphone output of a keyboard to the TRS or RCA line level input on the Soundcraft. That will result in an overload/distortion.

You can't sum the left and right channels without causing some phase issues. Remember that you need two TRS or RCA cables to make a stereo signal.

Posted: Thu Nov 22, 2007 6:26 pm

No, no Paypal; and anyway, I'm here to help - not profit. But I appreciate the offer.

I can't help thinking that you have something reversed or a button or knob turned that shouldn't be...

I'm really scratching my head on this one, it's just so simple. Output - input - done...
Sad

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