View Full Version : Problems with Logic 5.5 (PC) and GPO

Tom Hopkins
06-16-2004, 06:42 PM
Here is a summary of information on the use of Logic for the PC with GPO.


. . . and then there are the orphaned users of Logic 5.5 on PC (I’m one of them). . . Of all the platforms available right now Logic on PC has created some of the most vexing problems: Mod Wheel data that automatically resets to zero (even when you don’t want it to); stuck notes when a sequence is stopped in mid-stream and re-started from the beginning; volume data (cc7) that applies globally to the instance rather than the MIDI channel; etc. A nightmare.

We’ve been exploring various workarounds off and on for several months and, finally, I think we have found workarounds for virtually all of the problems. There are some compromises but these ideas at least make Logic usable:

Logic and GPO Studio

GPO cannot be used successfully as a plugin in Logic 5.5. There appear to be no solutions for certain problems when using GPO as a plugin. Some of the insurmountable problems are inherent in the way Logic handles VST plugins and the problems are never going to be fixed by Apple/Emagic – like it or not, it’s a dead platform. Instead of using GPO as a plugin, use Logic along with GPO Studio. One way to do this (that I have tested) is to create an Instrument object in the Environment for each MIDI channel of each GPO instance in GPO Studio – 64 in all. Name them something like: GPO 1 01, GPO 1 02, GPO 1 03, GPO 1 04, . . . GPO 2 01, GPO 2 02, GPO 2 03, . . . etc. Assign the output of the objects to the GPO Studio drivers (Personal Orchestra 1, Personal Orchestra 2, etc.) that should be installed on your computer. The eight objects for GPO 1 are assigned to Personal Orchestra 1 with each object assigned a different MIDI channel, 1 through 8. The eight objects for GPO 2 are assigned to Personal Orchestra 2 with each object assigned a different MIDI channel, 1 through 8. And so forth. These objects will appear in the track assignment tree and can be assigned as needed to your tracks in the Arrange window.

GPO Studio needs to be started first. Configure the Studio outputs to address your ASIO duplex drivers for your soundcard. Then boot Logic. If you have only one ASIO audio card on your computer Logic will complain that ASIO is not available. Ignore this warning and complete the Logic boot. This warning occurs because the present version of GPO Studio does not allow the user to deactivate selected multiple outputs on the card so Logic sees all available outputs as “in use.”

Once both applications are running load some instruments into the first two instances of GPO within GPO Studio. Assign Logic tracks in the Arrange window to address these instruments and set the GPO Studio reverb to taste. You should now be ready to record. This setup will not exhibit stuck notes and will allow volume data (cc7) to be used on separate MIDI channels of each instance so long as the “use std cc7 and cc10 volume and pan” option is activated in GPO.


The about-to-be-released version of the GPO player will have an optional version of the library that features an assignable slider for the Mod Wheel function. Mod Wheel data controls volume/dynamic timbre changes in GPO. In this new optional version of the library that function can be assigned to any of several choices including Mod Wheel, Breath Control, and cc11. If the slider is assigned to cc11 Logic will not exhibit the problem of resetting the data to zero automatically. If you wish to continue using your keyboard’s Mod Wheel to control volume you must create a transformer object in the Logic environment and cable it “virtually” between the MIDI (physical) input and the sequencer input. Configure the transformer to convert cc1 data to cc11 data (see the Logic manual for details). Your Mod Wheel will now control the volume/timbre but without the reset-to-zero problem.


Configuring your system to do the above will give you a working Logic/GPO system but without audio in Logic (since the ASIO drivers of the soundcard are being used by GPO Studio). One workaround for this is to install a second ASIO audio card in your computer – GPO Studio gets one, Logic gets the other. It should even be possible to then route the GPO Studio card’s outputs back to the inputs of the Logic card (watch the clocking issues if you go digital). This would also give you the opportunity to use the Logic effects on the incoming audio from GPO Studio. Multiple outputs/inputs between the two cards could give the user the flexibility to treat different instruments/GPO instances independently by assigning instruments to different outputs. This would also let the user take advantage of the “bounce” button in the Logic mixer. Otherwise, the new audio rendering function in GPO Studio can be used for a similar function.

These are the best workarounds we’ve found to date. They solve all of the major problems of Logic 5.5 but at some cost in convenience – not to mention a possible extra soundcard if you wish to have simultaneous audio tracks in Logic while using GPO. If GPO Studio someday adds the ability to selectively activate/deactivate the outputs for the soundcard’s duplex ASIO driver the need for the second audio card could possibly be eliminated.


03-15-2005, 04:37 PM

Thank you for exactly what I was looking for. I am just having a hard time giving up my Logic 5.5. I guess I refuse to change to a mac but might be willing to go to Cubase. However, all I really want is access to better orchestral samples (HD based) and stop the hassel of loading multi-cds everytime I boot my Kurzweils. (K2500X, K2600R)

Since you are working with both Logic and GPO, any new suggestions for me?

Thanks for any guidance.


Tom Hopkins
03-16-2005, 04:42 AM

This is probably not what you want to hear but I finally decided to move on. I've got both CubaseSX2 and Sonar4 on my main machine. Both are fine programs but I find myself leaning toward Sonar of late. Logic has been relegated to the far back corner of my hard drive. It doesn't get much sun in the afternoon and dust is gathering in its files but, unfortunately, it was time to say goodbye.


03-16-2005, 12:43 PM
Thanks Tom,

I was afraid you would say so... would you care to share the leaning more toward Sonar? I have one more project to finish on Logic, then I guess I'll take the plunge to a "forward supported PC based" program.

I have been to the respected sites... for Cubase/Sonar/and others but short of using each of them or relying on others to tell me their experience, I am walking in a fog in deciding which to buy.

I would have to assume that you coming from Logic as I, and knowing a lot more about what is out there and you chose to go with Cubase and Sonar, I would be OK with either.

I am looking for what I have in Logic today but ... you know... in my platform that will be supported.

I am open to any suggestions and guidance here.

Thanks again.