Bi-amping - my first forays

[Bottle]

As the topic suggests, this is a little thread to document my forays into bi-amping (and along the way, a few experiments in Tri- and Quad-Amping)

First off, I should mention the gear at my disposal (well, go see my gear thread link in the siggie) - I have a GK MB500 head which has lots of I/O options, and several bass-specific and PA-style cabs knocking about.

In more detail, I have an EBS 4x10 and a 1x15, plus a stack of 1x12 and 1x10 PA cabs (relatively low power handling), not to mention some chunky 19" rack-mount power-amps. So, my task was to utilise these for backline purposes, mostly for sh*ts 'n' giggles to see if it was at all possible to get a good sounding rig out of relatively cheap components (OK, so the GK and the EBS gear wasn't cheap, but at least most of it was S/H).

My first cab was the 4x10, which was a marked upgrade over the Line 6 1x10 combo I'd been lugging to gigs. I then spied a matching 1x15 for sale on here earlier last year, which I snapped up too. These went together remarkably well, although I was limited to using one or the other with my bass head, being that the cabs are 4 Ohms each and the head won't go down to 2 Ohms. I started using one channel of a stereo power amp to drive the 1x15 from the line out on the head. This worked well, and I also started using the other half of the amp when I got my SansAmp pedal to add a little drive to a pair of 1x12 PA cabs. The SansAmp gets it's input from the GK Efx Send/Return feed.

Some experimentation later and I started using a crossover to send just the clean lows to the 1x15 mixed in with some of the SansAmp drive. Highs from the SansAmp went to the 1x12's. This is my preferred tri-amping setup.

I've used this on numerous occasions including bass bashes last year, to some effect.

There have been several threads already on bass biamping too, which I have read and digested. Some very useful information contained in those pages.

Now to my current experiment.....

I recently purchased a Bass Big Muff Pi off of a member here, and immediately set to work trying to get a quad-amp setup working. To start off I used my current tri-amp rig unmodified and drove the GK's input from the 'Dry' output of the Muff. The 'Effected' output went to my trusty Line 6 combo, and used the DI out to go to the PA desk as a second input. Took the 'Clean' out from the SansAmp, setup using the default 'Active Bass simulated' setting in the manual as primary PA desk input.

It then got my thinking about balancing the various amp levels, so I looked at inserting the BBM in the GK's effects loop. I've heard that this doesn't always yield good results, but TBH I've not found it to be a problem. Signal chain is a little more convoluted now - GK Effects send > SansAmp input....SansAmp parallel out > Bass Big Muff Pi.

So:

[i]GK power section > [b]EBS 4x10 (clean, full-range)[/b]

GK Line out into channel A of X-over (f[sub]o[/sub] = 200Hz)
SansAmp effected output straight into channel A of stereo Power Amp > [b]two 1x12 PA cabs (smidge of drive, approx. 60/40 dry/wet blend, full range)[/b]
BBM Pi effected output into channel B of X-over (f[sub]o[/sub] = 150Hz)

X-over low-summed output into channel B of stereo Power Amp > [b]EBS 1x15 (<200Hz, mix of clean and fuzz)[/b]

X-over channel B High output into channel 1 of second stereo Power Amp (bridged 8 Ohm/500w) > [b]one 1x10 PA cab (>150Hz, fuzz) (for testing only)[/b][/i]

That's about it. I might replace the second power amp driving the single 8 Ohm cab with a suitable valve head and monster guitar cab

Feel free to leave comments!
Ian

[escholl]

holy phase issues, Batman. Still, if it sounds good...

[Bottle]

[quote name='escholl' post='1269216' date='Jun 14 2011, 09:05 PM']holy phase issues, Batman. Still, if it sounds good... [/quote]
Haven't tried it at serious gig volumes yet - this is aimed more at a recording/re-amping setup to give the rec. engineer a lot of flexibility at the mixing stage. Just trying different stuff out to see what works and what doesn't - mostly planning out what I need to do to isolate cabs from each other during trackig etc. It does kinda work in a live environment, but I'm taking on board the phase issues as well.

HTH,
Ian

[JTUK]

I wouldn't bother... and to my knowledge the GK head isn't a proper bi-amp option anyway..
but in the interest of expeimentation..I wager this isn't worth the effort.

Well..?? was it..?

To me, for bi-amping to work.. you need 2 power sources and a varibale x-over..so you send to a sub unit and a top unit.

Out of the quality cabs you have.....send the lows to the 115 and the higher end to the 410..but I'd think the 410 would sound pretty ugly with a passed signal...IMO.

[Bottle]

[quote name='JTUK' post='1269260' date='Jun 14 2011, 09:35 PM']I wouldn't bother... and to my knowledge the GK head isn't a proper bi-amp option anyway..
but in the interest of expeimentation..I wager this isn't worth the effort.

Well..?? was it..?

To me, for bi-amping to work.. you need 2 power sources and a varibale x-over..so you send to a sub unit and a top unit.

Out of the quality cabs you have.....send the lows to the 115 and the higher end to the 410..but I'd think the 410 would sound pretty ugly with a passed signal...IMO.[/quote]
Could well be right in the long run, but hey, if I didn't do it, someone else would, right? Besides, that's how progress is made LOL

This was my inspiration:



HTH,
Ian

[escholl]

[quote name='Bottle' post='1269252' date='Jun 14 2011, 09:31 PM']Haven't tried it at serious gig volumes yet - this is aimed more at a recording/re-amping setup to give the rec. engineer a lot of flexibility at the mixing stage. Just trying different stuff out to see what works and what doesn't - mostly planning out what I need to do to isolate cabs from each other during trackig etc. It does kinda work in a live environment, but I'm taking on board the phase issues as well.[/quote]
hmm, I'm not sure that it's as helpful as you might think, IME if anything it might make mixing more difficult. For mixing flexibility, a full-range dry signal (like a DI) and a full-range effected signal (mic'd up bass cab maybe) are really all that you need. From these, anything else can be re-amped or filtered.

obviously though, do whatever works best for you.

[ThomBassmonkey]

I'd be interested to hear the results. It does sound a very complex solution to a problem that doesn't exist IMO though. I use a GK MB Fusion which is a very similar head to yours and I'd imagine it'd sound fine full range with the EBS cab on it's own.

I'd be very careful every time you set it up, move around the room listening carefully for phase problems. With that many different speakers set up next to each other, you'd be lucky to escape scott free.

[JTUK]

My experience of bi-amping was that the amp was 200/200 into 4 ohms..so 200 watts was the most I could squeeze out of the amp.
The sounds was pretty decent and I ran 115 and 210, but not that much worse that 400 bridged into the same cabs.
I maybe preferred the split sound but I wanted/needed the extra volume.
The variable x-uver was a must though and provide the most flexibility of sound, IMO.
Without a variable X-over, not worth doing.

[Bottle]

[quote name='JTUK' post='1269390' date='Jun 14 2011, 10:55 PM']My experience of bi-amping was that the amp was 200/200 into 4 ohms..so 200 watts was the most I could squeeze out of the amp.
The sounds was pretty decent and I ran 115 and 210, but not that much worse that 400 bridged into the same cabs.
I maybe preferred the split sound but I wanted/needed the extra volume.
The variable x-uver was a must though and provide the most flexibility of sound, IMO.
Without a variable X-over, not worth doing.[/quote]
Similar to my power amp, 200w a side into 4 Ohms. EBS 1x15 gets one side, the pair of 1x12 PA cabs gets the other side.

X-over is variable too, input gain and relative levels of the low and high-pass outputs, with adjustment in the x-over frequency, minimum f[sub]o[/sub] is approx. 125Hz, max is 1KHz, and I have a 10x range available too, and if needed it can be changed from stereo two way with low summed out, to mono three-way.

Like I said before, it's all an experiment. I'll try to record some clips at some point.

I have some ideas I'm working on at the moment, and it would be handy for me to track everything in one pass, then I can mix the tracks later to get the effect I'm after. I'm also looking at getting a re-amping box to go with my PC interface - BTW anyone got one going spare?

Ian