Modulated delay in mono

[thejacobclark]

I've had my FM9 for about six months and the unit sounds absolutely glorious in stereo. However, I've been repeatedly encountering an issue I don't know how to solve: modulation on delays sounds like crap when I need to sum to mono. This sounds worst on the stereo tape but better on the Stereo Mind Guy and some other analog types; all sound wrong period to my ears. My L/R ratio is at 100% unless I'm deliberately trying to get different note values (i.e. 1/4 + 1/8dot), and I've experimented with the LFO phase offset in the delay block to try to fix the issues, but it doesn't seem to get rid of the problem entirely. Not using modulation seems to solve the problem, but I'd like to try to keep it in the signal if at all possible. I've read all the manual and wiki sections about stereo vs. mono and summing and delay parameters, but I still feel lost in trying to accomplish my goal of having my stereo cake and eating it in mono too.

 

[jlynnb1]

I've had my FM9 for about six months and the unit sounds absolutely glorious in stereo. However, I've been repeatedly encountering an issue I don't know how to solve: modulation on delays sounds like crap when I need to sum to mono. This sounds worst on the stereo tape but better on the Stereo Mind Guy and some other analog types; all sound wrong period to my ears. My L/R ratio is at 100% unless I'm deliberately trying to get different note values (i.e. 1/4 + 1/8dot), and I've experimented with the LFO phase offset in the delay block to try to fix the issues, but it doesn't seem to get rid of the problem entirely. Not using modulation seems to solve the problem, but I'd like to try to keep it in the signal if at all possible. I've read all the manual and wiki sections about stereo vs. mono and summing and delay parameters, but I still feel lost in trying to accomplish my goal of having my stereo cake and eating it in mono too.

question, if you're summing to mono why not use the non-stereo versions?

 

[thejacobclark]

question, if you're summing to mono why not use the non-stereo versions?

That’s definitely a possibility with everything but the stereo tape because the algorithms are different. It’s just one of those things where I really like the sound in stereo through headphones or speakers so I’m trying to have one size that fits all. I’ll have to play around with the mono versions, though, because I don’t know if the modulation section is in mono too.

 

[mr_fender]

There is no distinct modulation section of the delay per se. It's the same delay lines (one for each channel) and the delay time is being modulated (changed). For example, if you have your delay set to say 500 ms, the actual delay time will vary between something like maybe 490 and 500 ms at the rate and shape determined by your modulation LFO settings. How much the delay time varies depends on the depth setting of the LFO. In a stereo delay it's modulating both delay lines at the same time, but they are still separate signals, so if it's a stereo delay, the modulation is stereo as well. Some stereo delays have one channel phase reversed for a widening effect, but this causes cancellation when they are summed to mono. Also any phase offset in the modulation LFO between the two channels can also cause phase issues when summed to mono. Some stereo effects just don't work well when summed to mono. The option there if you need mono is to use just one of the channels instead of summing them together.

Phase artifacts are often most noticeable in the upper mids and highs, so that's probably why the warmer analog delay types don't show the issue as much.

Your best bet is equal delay times per channel and no LFO phase offset between the two channels. That should keep the two channels phase aligned.

 

[JoKeR III]

Try the Multitap Delay block, there are more modulation options and parameters available that may help. Use the Level parameter in each delay to 'turn off' the ones you don't need.

 

[thejacobclark]

There is no distinct modulation section of the delay per se. It's the same delay lines (one for each channel) and the delay time is being modulated (changed). For example, if you have your delay set to say 500 ms, the actual delay time will vary between something like maybe 490 and 500 ms at the rate and shape determined by your modulation LFO settings. How much the delay time varies depends on the depth setting of the LFO. In a stereo delay it's modulating both delay lines at the same time, but they are still separate signals, so if it's a stereo delay, the modulation is stereo as well. Some stereo delays have one channel phase reversed for a widening effect, but this causes cancellation when they are summed to mono. Also any phase offset in the modulation LFO between the two channels can also cause phase issues when summed to mono. Some stereo effects just don't work well when summed to mono. The option there if you need mono is to use just one of the channels instead of summing them together.

Phase artifacts are often most noticeable in the upper mids and highs, so that's probably why the warmer analog delay types don't show the issue as much.

Your best bet is equal delay times per channel and no LFO phase offset between the two channels. That should keep the two channels phase aligned.

Phase offset to 0 worked. I think my ears were a bit fatigued when I tried to fix the issue at first. The modulation still does not sound nearly as good in mono, but the phase offset fixes the major problem I was having with alignment. Thanks!