The unexpected but long awaited firmware release for Meridian processors brought finally a fix for the Trifield width bug. No reverse engineering is necessary to see that only DSP-C is updated (to revision 55), so it is reasonable to suspect that this will contain the Trifield processing. Just uploading this single firmware confirms this suspicion and the Trifield width now functions properly.
However, there is something else that is noticable immediately: it sounds differently, even with the width set to 1.0. The first impression is, in agreement with the general consensus on the Meridian Unplugged forum, that it sounds better. Unfortunately first impressions can be deceivable, and I mistook different for better. On continued testing it appeared that the lows were struggling and the highs were harsh. At first impression this can be mistaken for tight bass and added detail, as I also did. I was really unhappy with this new sound, so I decided to downgrade again to revision 52 of DSP-C. This solved the problems and the sound was as smooth as before.
DSP-C is used across the entire processor line, 568.2, C61R, G61, G61R, G68 and 861. Different versions can be loaded in every processor, so an older version from the 861 will work in the G68, but also the latest version from the just released updates will work in the 568.2. Over the years several revisions have been released:
| Revision | Firmware | Trifield width working |
|---|---|---|
| C0003b | 861 v4.02 | Yes |
| C00044 | 861 v3.51, 861 v4.1 | Yes |
| C00049 | 568 v2.5b9 | No |
| C0004c | 861 v4.2 | No |
| C0004e | G61 v1.02 | No |
| C00051 | 861 v4.25 | No |
| C00052 | G61R v1.01, G68 v1.44 | No |
| C00054 | 861 v6.02 | Yes |
| C00055 | G61 v1.11, G61R v1.07, G68 v1.5, 861 v6.03 | Yes |
I had heard that on the older firmwares the Trifield width worked, so I loaded revision 44 into my G68. And indeed, the Trifield width works perfectly fine! This means that we had a solution for the Trifield width bug all these years under our nose. And again something else is noticable: the sound is very, very clear and precise. It is as if newer versions are more processed, more artificial sounding.
So if you have an older processor and can not get the latest firmware or just want to play around with a working Trifield width, you can download the old 861 firmware from this page (you gotta love the internet archives). When you upload C00044 to your processor just ignore the warning that it is only suitable for the 861. After uploading your processor will give the “bad code combination” message. You can also ignore this. Have fun, and don’t forget to report your experiences here!
Important Notice: you have to reboot your device (turning it off and on again using the power switch) after uploading any firmware. Otherwise it may not sound as intended.
P.S. If you have an older version of the firmware for your processor with a different version of DSP-C, please let me know!
Mr Apodizer's Blog 
Very Interesting.
Any idea what version of DSP-C was used in G61R/G68 Speaker Link models prior to the latest update ?
Most likely C00054 as with the 861v6, since the SL models also already contained the apodizing filter.
Thanks.
The reason I ask is info from a popular forum premium partner suggested the TF width setting was known by M to be broken on the SL models and awaiting a FW fix.
If you own a SL model yourself, you can see the version of DSP-C quite easily by toggling through the version information: Press the button labelled ‘More’ on the unit when it is in standby. Then press the button labelled ‘Version’ repeatedly to toggle through the firmware info.
Is it known if the Direct “headroom” change in the latest firmware release is a function of DSPC or another firmware file i.e. file containing the filter element? These appear to be the only file name version changes between the previous and new firmware release.
I’m thinking here about Direct mode and if it’s still appropriate to use the +3dB config tweak when using the official apodizing filter element included with the latest firmware but with DSP C000044 rather than C000055.
Thanks
Using C00044 works great in my G68D. Thank you so much for sharing your insights and the results of your research on Meridian software/firmware.
Hello,
I have a little question . When you listen a CD , and use Trifield with DSPC00044 , do you turn down the center channel level?
If yes, how much
Thank’s
No, I have all settings on defaults. However, if you feel the center should be turned down, you should try that and see how that works out for you.
I’m a bit late to this party.
But I would still love to test out DSPC00044 on our Meridian 568.2mm (currently running 2.5b9).
How to exactly flash the DSPC00044 is not entirly clear to me.
Do I have to run the Meridian Flash Uploader program, and only upload the c00044.mfu file ?
And can I also return back to the original DSPC00049 from 2.5b9 from our 568.2mm ?
I hope to see some answers, thanks in advance,
Yes, only upload c00044.mfu using the Meridian Flash Uploader program, and to revert back to the original only upload the c00049.mfu file.
Great, thanks for your response !
I was also wondering are there any other known compatible c files which are compatible with our 568.2mm ?
For example is there more than just DSPC00044 I can perhaps safely test ?
After doing some research over on the Meridian unplugged hitchiker forum, seems like users over there reported that C0003b also works on the 568.2.
Perhaps you also have some information on this.. ?
The web archive link in this article still works ! 🙂
And I was only just then wondering, do I need the c00044.mfu from the 861v4 or 861v3 ?
Or are they both the same file perhaps.. ?
Looking forward to your response, thanks in advance !!
I am pretty sure all versions of DSP-C will work, at least they did on the G68.
There will be no difference in a particular revision of DSP-C in different firmwares, it is exactly the same file.
Great, Thanks so far Mr Apodizer !
I can confirm that at least C00044 C00055 and C00057 do work with the 568.2 processor.
And going back to the original c00049 is also very easy, using the Meridian Flash Uploader !
I hope someone else also benefits from this information.