Help needed: GP-10 GR-300 possible Issue [patch and audio included]

Started by LNS, September 26, 2023, 08:55:53 AM

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   I'm fairly new to the BOSS GP-10, but I'm a previous user of past Roland Guitar Synth units such as VG88V2, VG8, GR33.
 I also was one of the first to buy into the pitch to MIDI technology with the Kramer IVL Pitch Rider that came out in the 80's.  I just saw this in my garage. I thought I had sold it (LOL), but it's still around.  I'm also a fan of Pat Metheny since the late 70's and always dreamed of having the best GR-300 tone with ADSR control for filters and amplitude (the original GR300 does not have this control). I've prayed my entire life, Roland/BOSS would offer this capability.  Well, Roland certainly headed the right direction.  I hope they continue.  Franky, I'm not really sure where we would be as musicians today without Roland/BOSS. This company has created the sounds we love for decades!

Okay, onto my issue I'm hearing with my GP-10 using the GR300 [VCO] synth:

NOTE: I should state, I've only paid attention to this issue around the GR300 Synth model VCO, not with other synth models in the GP-10.

  I'm having a strange overtone with the GR300 VCO synth which gets worse as you play higher notes.  It sounds like either an aliasing issue or some kind of modulation that increases as you play higher notes up the fret board.  This really destroys the quality of the GR300 tone. It's almost like pig squealing noises that increase as notes got higher. If this an aliasing issue. I wonder if Roland/BOSS should have put a brickwall filter just prior to the input of the GR300 synth model. Though, I'm concerned this is a problem with my GP-10 and may not be an issue with yours.

I have included a patch GR300_TEST file to try yourself.  I've also included two audio files.

1.  The first audio file GP10_GR300_T1.mp3 [This audio example was used to show the issue. This is the key of G starting on high E string [All notes played on this string]. I started on the 3rd fret up to the 15th.  Please use headphones or a good sound system. It gets progressively worse as notes get higher. 

2.  Possibly not related, the other thing I noticed is the same tone on different strings seems to have a slower attack on the different strings.  The second file GP10_GR300_T2.mp3 displays this question. Here's the note order you are hearing.  These are all G notes starting on the high E (string 1) 3rd fret.

Audio note order for GP10_GR300_T2.mp3:
1. High E string 3rd fret (G)
2. B string 8th fret (G)
3. G string 12th fret (G)
4. D string 17th fret (G)
5. A string 22 fret (G)

Since these all have the same pitch, I would have thought the attack time would all be the same.  I realize you will have a bit darker tone due to the lower strings have more bass response, but they are all the same exact frequency, so I'm confused why the notes have a slower response on the lower strings. They have kind of a "splat" to the attack.  It's not very pleasing. Is there something I'm missing here, or is the issue I'm asking regarding my first audio example tied to this?  I don't believe so, I'm just trying to make sense of this.

I'm asking for help to understand these two questions?  I bought the GP-10 two weeks ago and need to determine if I need to order an exchange for a new unit.

Please download both audio files and listen especially to the first test (GP10_GR300_T1) to help me determine If this overtone problem is only with my unit.  Also, if you can please upload the same test I did using the included GR300_TEST.tcl file. 

Thank you!
Great forum!  I'm impressed with all of the great information and patches!



Yep, that sounds a lot like aliasing which is in all units. It is very unlikely that your GP-10 is faulty.

It is so bad, it is baffling that Roland/Boss don't seem to care about it at all. If history is anything to go by, they will probably just use the same old DSP in future new products before addressing serious issues like this.


Quote from: susbemol on September 27, 2023, 03:46:17 AMYep, that sounds a lot like aliasing which is in all units. It is very unlikely that your GP-10 is faulty.

It is so bad, it is baffling that Roland/Boss don't seem to care about it at all. If history is anything to go by, they will probably just use the same old DSP in future new products before addressing serious issues like this.

susbemol, Thanks for the reply. It does seem like aliasing. I'd like to see someone try my patch I included and see if they hear the same issue. 
I know there are filter boxes that help NON GK pickups for subsonic frequencies. This targets low frequency mechanical noise that can cause false triggering. I wonder if someone were to design a LPF brick wall filter that could reduce aliasing issues. Well assuming aliasing is the cause of this pig squeal sounds in the GR-300 VCO model as you play higher notes? I imagine they could steep roll everything off (brick wall) at 8K, (or a bit less). I'm still a bit worried that there's a problem with my unit? It seems hard to believe nobody else has mention this issue?  It seems very strange since it sounds really obviously bad.


Unless I missed it somewhere, what guitar (and pickup system) are you feeding into the GP-10 ?

Read slower!!!   ....I'm typing as fast as I can...


Thanks Gumbo,
I have two different guitars, one with the GK-3, the other with a GK-2A. Both sound the same with my GR-300 VCO issue.
Thank you!


I've watched quite a few videos on the GP-10  demonstrating the GR-300 VCO model and have not heard the same overtone issue I'm hearing with my GP-10. I also have looked through hundreds of posts that have reviewed the GP-10 and can't find one person that has mentioned this same issue.  I take that my unit is defective. It would seem extremely hard to believe no one would mention this issue since it's absolutely horrible sounding. 
Any thoughts on this issue? I just listened to a video demonstrating the SY-1000 GR-300 model and it did not have this issue. I only mention this since the demonstrator happened  to play the model cleanly and I can hear the clarity even in higher notes. I'm not hearing the modulated pig squeal sounds as notes get higher as in my attached mp3 demo files above. I also heard this issue in the lower GR-300 VCO notes, it just gets a lot worse with higher pitch notes. Just for reference, here's the SY-1000 link I mentioned. Goto around 24:00 minutes in.


How are you monitoring your GP-10?

If its MONO, you may be experiencing phase cancellation from a summed stereo effect

I use Audio Technica ATH M40x or VMODA  headphones or a pair of QSC CP8 PA Monitors -each directly connected to GP-10 Outputs with no complaints of my GP-10 tones  in full stereo

I  use my GP-10 as Audio interface with my Win/Mac Computers.

Routing GP-10 outputs to third party mixers, audio interfaces , DAW apps introduces several potential sources of phase cancellation , which could act as a comb filter with high aliasing distortion


Thanks Elantric,
I'm monitoring in stereo- headphones or studio monitors , it all sounds the same.   I take you are not hearing the same issue I have with my attached posted mp3 files?
 Thanks for the reply,


Back up any user patches and perform a GP-10 System Reset

All Roland /Boss DSP gear requires periodic Reboot /Reset, to clear possible corrupted memory

GP-10: Factory Reset (Initialization)
Turn on the GP-10's power.
Press the SYSTEM button repeatedly until "Factory Reset" appears in the display.
Press and release the WRITE button. "ARE YOU SURE ? " appears.
Press WRITE again. "Factory Reset Now executing" appears for about 5 seconds, and then the main screen appears.

Mine sounds same as this


Thanks Elantric, I will try the factory reset and get back in a few minutes.


after a Factory Reset
Try the detailed GP-10 settings for GR-300 here


What is your 13 pin guitar type and what 13 pin pickup is employed

Your GR-300 mp3 examples sound nothing like my GP-10 on its GR-300 patch ,mine  matches Wayne Joness youtube GR-300 sound above using guitar with GK-3 13 pin pickup

Yours sound like a Casio piano;attach=31647


I have GK3 on one guitar and a GK2A on another. They both sound the same with the GR300 VCO model.  I only created this test patch to hear the pure GR-300 tone without effects.  I agree. This test tone sucks..LOL , but it will show the issue plain as day. I created this test since I heard the issue on all of the GR-300 VCO patches available.  The factory reset didn't change the issue. :(  Please load my patch and let me know if you also hear the horrible overtones (my test was all on the high E string- key of G going up to the 15th fret..)  it all sounds bad and get downright unbearable as the pitch goes higher.  Thanks for the help sir! 
I'm really bummed since I love this thing!  I may have to order another just to compare.


Post a pic of your GK-3 installation

If GK divided pickup is too close to bridge ( less than 20mm ) , this results in weak GK-3 output, requiring higher GK String Sensitivity settings, resulting in  enhanced overtones and less fundamental string pitch for GP-10 Modelling to operate with

Can GK-3 PU be too close to the bridge?


I am not sure everyone understands what is being discussed here.

It is very unlikely that the issue described by the OP is related to the instrument used or any individual GP-10 as at least I can easily reproduce it with two different guitars with internal GK3 kits and a Godin with piezos. The SY-1000 behaves in a similar way but it seems to sound not as bad, at least in my quick test.

Have a quick listen to these audio clips. The virtual GR-300 in the GP10 creates some atonal overtones that sound like aliasing. This is more easily perceivable at higher pitches with comp ON and the filter cutoff fully open, as suggested by the OP:

As also demonstrated, my analogue GR-300 does have some noise as the notes decay too but it does not sound quite as bad as the digital engine in the GP10 and SY1000.

Now, to be fair, this is rarely noticeable when I am actually making music so I tend to just not think about it and play.

PS: to the OP, if you close the filter a little bit (which I almost always do), it seems to also help.


  I was just about to post my latest info on this and noticed your message. Well, I bought another GP-10 and as you just mentioned, this GR-300 VCO model issue is inherent in all GP-10s. I was also able to try another unit. So I've tested three.

To answer Elantric's question, my GK-2A is at 20mm from the bridge saddle. My Les Paul which holds the GK-3 pickup with the included bracket only allows a 15mm spacing between the GK and bridge saddle. I also did  try a quick temp test where I moved the GK-3  around 20mm away. There was absolutely NO change with the weird aliasing issue with the GR-300 VCO model. My Gk height is the typical 1mm gap. Also, all of the other GP-10 models sound great and do not have this issue.

Susbemol, as mentioned in my first post, and as you also mentioned in your post, this sounds like aliasing. Like I mentioned before, it would be interesting if there was some sort of filter box placed between the GK pickup and the GP-10 which would help minimize this issue. If anyone knows of such a thing, please let me know? The filter box was just a thought and may not have anything to do with the aliasing issue. This issue may be internal during conversion. It would be great if an update could help address this issue. I don't believe the GP-10 has ever seen an update since release ten years ago.

I'm about to check out all your files on this. I was wondering if they improved on the SY-1000. I wasn't a real fan of the SY-300 sound and returned that a while back.

The patch I included was not for musical use, but only for testing- since it sounds like crap, but it will dramatically show the issue. I heard this issue when I first turned on the GP-10 during the first minute of using the GR-300 VCO stock patch.

Thanks for those test files. That was brilliant- I just listened to them.  This test and the three units I've tested concludes this issue is inherent with all GP-10s.  Interesting the SY-1000 has the same issue; although, a bit better.