HPF vs Parametric EQ for controlling rumble w/Streamliner and Thunderchild?

[sunbeast]

I'm assuming the HPF also doesn't affect the Aux Input?

 

[msmucr]

I've not tried it, but according to block diagram in Streamliner manual, HPF doesn't affects AUX input.

Michal

 

[johnk_10]

i realize that you probably want a small device for your solution, but whenever i want to find out what freq i want to roll off, i use my ashley DPX-200's adjustable HPF. each eq freq section is defeatable, so i just use the lowest band which is shelving.

here's a pic of one:

[Invalid or Expired Link Removed]

 

[steve_rolfeca]

Thank you all for a ton of useful replies.

The fact that the HPF is before the power amp input, explains why I still get the "rumble" with other preamps. The comments about filter slope etc., are useful as well.

The gear geek in me wants to get a rack EQ. Good ones can be picked up awfully cheap on the used market, but that would defeat my whole purpose in going with lightweight, micro gear.

I PM'd Duke about this, and he suggested trying to fix it in the acoustic realm rather than with EQ, which also jives with the suggestion to try an Auralex pad.

Now that I have a better idea of what's going on, I shall experiment some more, and report back.

 

[KJung]

Thank you all for a ton of useful replies.

The fact that the HPF is before the power amp input, explains why I still get the "rumble" with other preamps. The comments about filter slope etc., are useful as well.

The gear geek in me wants to get a rack EQ. Good ones can be picked up awfully cheap on the used market, but that would defeat my whole purpose in going with lightweight, micro gear.

I PM'd Duke about this, and he suggested trying to fix it in the acoustic realm rather than with EQ, which also jives with the suggestion to try an Auralex pad.

Now that I have a better idea of what's going on, I shall experiment some more, and report back.

FYI, the Auralex pad only impacts mechanical coupling, so would only have a modest impact on hollow stages. IMO, not worth the trouble (the port plugs would work just as well, if not better if you are in that extreme of a situation).

Best bet, put an EQ between the bass and amp to dial in a bit more mid presence. That negates any need for any sort of Hi pass filter (which is obviously not your issue anyway), and will allow you to punch up the lower and upper mid profile of the amp.

Again, not a great match IMO with these two amazing pieces of gear. The great news about the Thunderchild (versus the Acme or fEarful 12/6) is that it is 4ohms and relatively high efficiency, so you can literally choose virtually any head on the market in the 400-600 watt range, and the cab will perform to its full capability.

 

[agedhorse]

Correct.

I'm assuming the HPF also doesn't affect the Aux Input?

 

[will33]

FYI, the Auralex pad only impacts mechanical coupling, so would only have a modest impact on hollow stages. IMO, not worth the trouble (the port plugs would work just as well, if not better if you are in that extreme of a situation).

Best bet, put an EQ between the bass and amp to dial in a bit more mid presence. That negates any need for any sort of Hi pass filter (which is obviously not your issue anyway), and will allow you to punch up the lower and upper mid profile of the amp.

Again, not a great match IMO with these two amazing pieces of gear. The great news about the Thunderchild (versus the Acme or fEarful 12/6) is that it is 4ohms and relatively high efficiency, so you can literally choose virtually any head on the market in the 400-600 watt range, and the cab will perform to its full capability.

+1 to this.

The gramma stuff does work by providing a buffer between the rig and the floor. The big misconception is how those vibrations got there in the first place. Unless the cab is of poor quality, it does not vibrate. Soundwaves are what excite the flimsy stage floor, the rig then vibrates because it is sitting on the vibrating floor. The gramma separates the rig from the floor. It's still an acoustic thing initiating all this, the result is mechanical movement.

 

[steve_rolfeca]

Duke had suggested that I block one port. I don't even pretend to have his knowledge of cab tuning, so I'll quote his explanation: "My guess is that you're hearing the pitch shift in the direction of the port tuning frequency as the note decays."

Results were mixed. I found it helped, but wasn't a total solution. Blocking both ports was too much, even with corrective EQ.

Going back to my little Flite 103W was instructive. All the stuff I didn't like about the transition to the 4" cone midrange and the little Eminence horn tweeter was brutally evident. Still, the low end with the single downfiring Beta 10 was much tighter (at least within its limited dynamic envelop), and it didn't have the rumble that was bothering me with the TCAF.

My guess is that Duke was giving my ears too much credit. What I'm hearing is noticeable on the initial attack of the note, not just the decay. I think that after years of using small cabs with a fairly restricted low end, I'm just not used to hearing this much "whump".

 

[steve_rolfeca]

So, time for some more testing. As a diagnostic technician at AT&T, I used to find that my biases got in the way of finding answers, unless I deliberately set them aside. Nowadays, when I'm in investigative mode, I like to let go of what I know (or think I know), at least until it's proven to be true. Just try everything, and see what happens.

Using that premise, I went downstairs to the bat-cave, and dug out my old Yamaha desktop multitrack, which features 4-band fully parametric EQ. Further testing with it and other options revealed the following:
- Using just the power stage of the Streamliner, I really enjoy the sound of the Thunderchild with flat-response preamps, SS or tube. What a fabulous-sounding cab!
- However, when I substitute those other preamps, bypassing both the SL900's tube pre AND the HPF, I still hear the "rumble". Clearly, what I'm hearing is acoustic, and not caused by the "fatness" of the Streamliner's front end.
- The problem (if it even is one, and not just my tonal preferences), is not coupling with the floor. I tried various tilts, and even put the cab up on a primitive version of an Auralex pad. No dice.

Next, I tried outboard gear in the effects loop, to provide some extra EQ:
- The 80Hz switchable low-cut filter on my Mackie board is too high. Turning up the bass fattens things back up, but the open E, and especially the B string, don't sound convincing. The sense of effortless power and punch is lost.
- Switching out the mixer for the Yamaha, the parametric EQ actually worked pretty well. Setting the first band as a HPF, I found that between 35 and 40Hz, I could feel a slight reduction in the "rumble" when I stood over the amp (in terms of a sense of pressure on the ears).
- Standing out front, there was no negative effect on the tone of my bass, if that makes any sense. The effect was subtle, less than blocking a port.
- In order to beef up the action of the HPF, I tried adding a narrow notch of about 6-12dB on band 2. With the frequency set around 40Hz, that helped some more.
- i hit paydirt when I ditched the HPF, and tried a bandpass cut of about 5 or 6dB at around 50-60Hz. The woof, rumble or whatever, was gone, with or without a port blocked.

Mind you, all of this was at livingroom levels. I will have to hit my rehearsal space in the next couple of days, and see what happens at gigging volume.

 

[steve_rolfeca]

With that problem solved, I went on to fool around with a couple more bands on the parametric. The key seemed to be the ability to vary the filter shapes, compared to the fixed and very broad, "old school" tone controls on the Streamliner.

With the Streamliner's gain set fairly low, the tone controls set to minimize the amp's natural voicing (bass at 9-10 o'clock, mids at 220Hz and cut to 9 or 10 o'clock, treble cut slightly to taste), and by using the parametric to boost 600Hz with a fairly narrow bandpass, and applying a fairly broad hump centered anywhere between 2.5 and 4K, I could dial up various degrees of "Shuttleness".

With the right settings, the amp still retained that Streamliner warmth, while getting quite "quick" and modern-sounding.

As others have pointed out, the Thunderchild is very "transparent", in the sense of faithfully reproducing the voicing of whatever amp is driving it. With this Frankenstein rig, I was able to dial up some very aggressive sounds, despite the supposedly polite nature of the TCAF.

Interesting indeed!

 

[zombywoof5050]

..the 10meg ohm input impedance is fine for your electric. problems occur when the input impedance is too low, but not usually from it being too high. it will let all your frequiencies come through rather than bleeding off the low end, then you can tame it with the filter..

I thought it was the high frequencies that bleed off when the input impedance is too low.

 

[johnk_10]

IME, it's actually all frequencies including the low end.

 

[shwashwa]

I thought it was the high frequencies that bleed off when the input impedance is too low.

no, not with a piezo pickup at least. if i plug my upright into an imput with a low impedance i get all finger noise and piezo quack. when i use the proper buffer before the same said input, the sound is full like its supposed to be, with the lows back in. lots of posts about this on the DB side... i think in the summit audio thread because it has an adjustable input inpedance.

 

[zombywoof5050]

Ok, thanks.
I was mostly going by what I've heard about plugging a passive bass into a passive DI with a relatively low input impedance (JDI for example), everyone says the high end suffers.

 

[Ric Vice]

FYI, the Auralex pad only impacts mechanical coupling, so would only have a modest impact on hollow stages. IMO, not worth the trouble (the port plugs would work just as well, if not better if you are in that extreme of a situation).

Yeah, Ken you're absolutely right, but I hate using the port plugs unless have to, because it changes the low end. That's why I go in little baby steps, (abet the fact, that the Gramma is a big, finicky, chubby, little baby) and sometimes the Auralex works in the Sheldon or Winndfred Moore Auditorium here in St. Louis. It's just enough to get me out of boom city, without putting the plugs in the Thunderchild. Fortunately, the Walter Woods Ultra is voiced very differently than the Streamliner so I can also EQ the problem out of the mix. Next time I'm at one of those halls I'll experiment with the plugs.

Ric

 

[GrowlerBox]

So, time for some more testing. As a diagnostic technician at AT&T, I used to find that my biases got in the way of finding answers, unless I deliberately set them aside. Nowadays, when I'm in investigative mode, I like to let go of what I know (or think I know), at least until it's proven to be true. Just try everything, and see what happens....

For some reason, I really enjoyed this post; perhaps because it mirrors some of my recent travails in getting a piezo pickup to work, blending various mics into my signal, etc (all on DB, though).

Thanks!

 

[1n3]

So, time for some more testing...
... i hit paydirt when I ditched the HPF, and tried a bandpass cut of about 5 or 6dB at around 50-60Hz. The woof, rumble or whatever, was gone, with or without a port blocked.

An interesting read; thanks. Illustrates the value of powerful tone controls in the hands of someone who understands them.

 

[agedhorse]

Sometimes a very high input impedance can cause underdamping of a piezo elemet, 10M is plenty high to be a cause of this with sime pickups. I find that between 500k and 1.5Meg is good for most piezos (except VERY small crystals which are not generally used in bass guitar applications.)

When I was designing pickups, I spent a lot of time testing damped responses and these are my conclusions/.

 

[steve_rolfeca]

I spent a couple more hours playing with the parametric in the Streamliner's effects loop.

Sheer bliss. Reinforces why I bought the Streamliner in the first place. And the Thunderchild. I'm really happy that I've found a way to make these two amazing products play together well.

Now, to find a workable arrangement. Carrying a huge desktop multitrack recorder to all my gigs isn't going to cut it. In fact, with my chronic back trouble even a rack unit is iffy, so I ordered an Empress ParaEq late last night.

Will update once I have a chance to check it out on the gig.

 

[MarkA]

Enjoying following this process. Interested to see what you come up with.