EHX Russian MUFF into VT Bass - Investigation on missing mids!

[heavyfunkmachin]

Hi,

I love my VT bass, I use the deluxe version live and recently got the VT Bass DI at home. I also love the EHX Green Russian reedition. BUT I was always fighting the Muff live, it felt like I dissapeared in the mix!!

So I whipped out the REW software and found quite a puzzle. Join me for this amazing ride!

This is the frequency response of the russian muff while sweeping the tone know from min to max:

As you can see I it looks really good, healthy lows, small mid dip and highs cutted or boosted.

Now, this is a VT bass DI setting 100% wet with bite, speaker sim, drive at 11 and eq to be flatish:

Now, feist you eyes on what happens if I engage the Muff into the VT bass (Muff with tone at max and VT bass with same settings as above):

THAT is what I was hearing live that made mee dissapear in the mix! Somehow the Muff with boosted highs interacts with the VT bass and steals the mids away!!

I tried to find out why this happened, and Found out that it is due to the VT bass "bite" switch being active, as you can see here (same settings on everything but BITE is off):

It is REALLY weird, as the BITE is only supposed to be be engaging a bit of low end filter (tiny) and a healthy boost in the highs, as you can see here with VT Bass with and without bite:

It's almost as ig the boosted highs from the BITE interact with the mid's phase and create that deep hole in the mids by cancelling... I tried to replicate this by feeding the muff into the VT Bass with BITE off but with highs boosted: no hole in the mids.
I tried clean signal with boosted highs with an EQ before the VT bass with bite off: BINGO. If I boost highs before the VT bass the hole in the mids appears!
You can see it here: muff into VT bass without bite, with a 7db boost in the highs between muff and VT bass and with a 12db boost between the muff and VT bass

SO, What have I learned about this?
- The bite switch (or standard VT bass sound in the VT bass deluxe) means a very insignificant low end roll off and a heavy boost to the highs (8-10 dbs) and it appears to be a boost at the beginning of the chain (before drive and EQ)

- VT bass has a strange reaction to being feed a lot of high end, the boosted highs from the muff with tone open plus the bite switch (or standard VT bass sound in the VT bass deluxe) cause the mids to be cut HEAVELY, It feels like it's too much and it bounces back to eat the mids in a very phasey way (extra screnshots below for reference)

- EHX green russian is a fuzz with a lot of highs, so feeding it into the VT bass DI with the Bite on or the deluxe (or old verions) actually make the tone knob a mid scoop noob in a way: you boost highs sligly but it EATS your mids away

- This means I can't use my muff into my VT bass deluxe as it has no bite switch unless i'm ready to accept my mids being murdered. The good side is that now i know I was not crazy on what I heard. Downside is that this makes me very very sad
I could use it with the VT bass DI with the bite off and a boosted mid know to compensate., but I liked the bite sound and I cant dessengage it in the VT bass deluxe

- I'm still puzzled at why this happens, perhaps @tech21nyc can share some insight?

Thanks for reading so far...


Extra images: showing the mid's phase issues
Muff>VT bass BITE OFF

Muff>VT bass BITE ON

Muff>EQ with highs boosted> VT bass with BITE OFF

 

[heavyfunkmachin]

Afterthough and question for @tech21nyc - Is there a mod for the VT bass deluxe to dissengage the bite filter? (I recall there was one for the speaker sim by cutting a trace in the board, but I cant seem to find any mention to the Bite being off in the deluxe)

 

[crguti]

It always good advice to plot the phase response too. The mid cut could be happening due to phase issues when summing signals in parallel, but you mention the VT bass was 100%wet... so that part is puzzled (unless it is not 100% in your circuitry).
The bite switch is at the beginning before the gain. Actually I modded mine with a bit less bite (by replacing a capacitor), so the treble control doesn't saturate so much when it's at max.

 

[heavyfunkmachin]

It always good advice to plot the phase response too. The mid cut could be happening due to phase issues when summing signals in parallel, but you mention the VT bass was 100%wet... so that part is puzzled (unless it is not 100% in your circuitry).

The bite switch is at the beginning before the gain. Actually I modded mine with a bit less bite (by replacing a capacitor), so the treble control doesn't saturate so much when it's at max.

I'm positive there is no blend (100% wet), actually dialing in dry signal reduces this mid cut, so I'm fairly positive it's caused dueto feeding a lot of highs to the VT bass (either by external EQ or the Bite switch)

 

[MtManiac]

Interesting - I'll have to make a point of bypassing the EQ in my VT Bass DI when I engage my muff. I've heard this too and complained bitterly about it to my band mates, to which my guitar player shrugged and said "that's what muffs do."

 

[heavyfunkmachin]

Interesting - I'll have to make a point of bypassing the EQ in my VT Bass DI when I engage my muff. I've heard this too and complained bitterly about it to my band mates, to which my guitar player shrugged and said "that's what muffs do."

How would you bypass the eq in the vt bass di? Regarding muffs' mids, some do but as you can see above the russian does not do it that much!

 

[MtManiac]

How would you bypass the eq in the vt bass di? Regarding muffs' mids, some do but as you can see above the russian does not do it that much!

You can just click the bypass button - still works as a DI, but without all the VT Bass stuff added. Aka "turn it off".