Booming at certain frequencies

[Monz]

Booming frequencies seem to be the bain of my life..

Used to have a Warwick Corvette playing through Markbass 1 x 15 - 2 of the venues we play regular -booming resonance on A

Now got a Stingray 5 through a Mesa Boogie 2 x 10 - 2 different venues booming around A and D

Just ordered one of those Auralex GRAMMA platforms as I believe it can only be the resonance between the amp and floor or the rear port (The last 2 gigs done with the Mesa have been on wooden floors). I played the mesa/stingray in a rehearsal studio last week and it sounded awesome so all other things being equal I reckon it has got to be the amp/floor interface. I am presuming a large blanket or similar behind the rear port of the amp will deaden the reflex frequencies (if there are any)

If anyone has any quick fixes for this you will forever be my hero

cheers

[Stewart]

Generally I just have my rig as close as possible to as many walls as possible (within a few inches in a corner suits me very nicely).

Then there's EQ - I really don't use much, but any I to cater for the room rather than to generate 'my tone' (probably because I don't have one:) )
I have a 10m lead, so I can go for a wander...

I also use a hint of compressor - which might help you if any of those 'high spots' is due to peaks in the pickup response or any EQ/pedals in use.

Multiple sources (such as when you're using a loudish rig *and* going thriough the PA can be even harder to deal with.

I doubt there are any 'quick fixes' that would apply in most cases though - it's always a compromise.

[Marcus]

Hi
I guess we've all had those boomy gigs when using big backline in small venues....

If you're using the Boogie Buster it's obviously All Valve..... are the Valves in good order ? old output valves won't provide a tight focussed low end, they'll have the potential to sound wooley and loose. If they have deteriorated they may have become microphonic which sounds horrible at volume.

I've just purchased an Auralex GRAMMA myself and it's one of those rare products that actually does what you'd hope it does.... simple but very effective

ATB

Mark

Edited May 26, 2009 by Marcus

[Kiwi]

The solution could potentially be quite simple. Knock back the frequencies between 60-100Hz on your graphic (or even better, use a parametric eq for accuracy) until the boom subsides but the bass retains some warmth. If you're using a parametric eq, use another band to boost around 250Hz to reintroduce some kick. I have a 4 band parametric eq in my rack based rig and I'll probably never go back to a graphic eq.

EDIT: Use the above as a general guide for stage boom. I've just re read your post and noted you're using a 2x10 with a 5 string which hasn't worked very well in the past for me. I've found that while 2x10"'s are capable of producing some low frequencies, that range isn't defined very well. I'm wondering if the 2x10 might be part of the issue as well? I switched to a set up which was a little more modern sounding. The EBS cabs definitely aren't boomy sounding at all which is why I liked them. Definitely have a play with a parametric eq though if you get a chance. They're great for nailing specific problem frequencies.

[Monz]

Thanks for the advice everyone...

Will see what the Auralex does and then EQ the bottom out a little if it doesn't sort it, will start looking for a parametric, I presume you can buy these as a pedal/rackmount unit?

Thanks again

[Kiwi]

[quote name='Monz' post='498475' date='May 27 2009, 06:22 AM']Thanks for the advice everyone...
I presume you can buy these as a pedal/rackmount unit?[/quote]

Sure, a range of solutions at different price levels but I haven't tried them all so can't comment on their effectiveness.


[url="http://www.bossarea.com/loadpage.asp?file=boxes/pq3b.xml"]http://www.bossarea.com/loadpage.asp?file=boxes/pq3b.xml[/url]


[url="http://cgi.ebay.com.my/tc-dual-parametric-equalizer-original-not-reissue-RARE_W0QQcmdZViewItemQQitemZ190281275727"]http://cgi.ebay.com.my/tc-dual-parametric-...emZ190281275727[/url]


[url="http://www.bhphotovideo.com/bnh/controller/home?O=&sku=284950&Q=&is=REG&A=details"]http://www.bhphotovideo.com/bnh/controller...G&A=details[/url]


[url="http://www.bassemporium.com/detail.php?FeQ-50"]http://www.bassemporium.com/detail.php?FeQ-50[/url]

I use one of these:


[url="http://www.tlaudio.co.uk/docs_07/product_07/5013.shtml"]http://www.tlaudio.co.uk/docs_07/product_07/5013.shtml[/url]

But I haven't gigged it yet.

[foal30]

well the Boss PQ-3B is on my pedal board
and I think 5 string bass means 15" speakers.

potentially not as cheap a solution as a blanket under your cabinet though.

[51m0n]

You need a notch filter. Which is an extreme setting on a fully parametric eq. IE maximum gain reduction, minimum Q (bandwidth) at exactly the correct frequency

My BP8 had one built in which was brilliant, esp as you sweep the frequencies with the wah pedal! Set and forget too until a power cycle, 'kin brilliant. Would love to find another device like this....

[quote name='foal30' post='498495' date='May 27 2009, 08:25 AM']well the Boss PQ-3B is on my pedal board[/quote]

Do you know how to use it like a notch filter rather than for tone shaping?

{maximum gain reduction, minimum Q (bandwidth) at exactly the correct frequency}

Really ideally you need a Q that is literally a few Hz wide at most at the low frequncies you are dealing with, maybe only a single Hz is actually required in some rooms.

[quote name='foal30' post='498495' date='May 27 2009, 08:25 AM']and I think 5 string bass means 15" speakers.[/quote]

With all due respect thats utter plop.

Its a function of cabinet design not driver diameter.

For instance my stereo has 6" drivers, but being old school TDL transmission line cabs it goes down to ridiculous depths (around 25Hz on my Studio 0.75Ms)

My berg ae410 easily handles my low b and never ever farts out, not even close, at crushing volumes.

10s, 12s and 15s can all do low notes at high volumes in a correctly designed enclosure.

[quote name='foal30' post='498495' date='May 27 2009, 08:25 AM']potentially not as cheap a solution as a blanket under your cabinet though.[/quote]

Thats not a solution.

Boominess is almost always a function of standing waves and resonant room frequencies, not some perceived coupling with the stage - its the entire physical shape of the room more often than not.

Also the width of a blanket is not going to make any diff, most stage coupling is not mechanical (if it were then your cab would be bouncing around like mad due to the amount of vibration emanating of the side panels). Its acoustic coupling, in which case you need to be well over 2 feet away to decouple if I remember correctly. The auralex pads are great for preventing downstairs hearing you bashing a drum kit, or that energy being transmitted directly through the floor to a not prperly decoupled control room. They wont make so much diff on a stage, cos that isnt the solution to the problem.


Point to note though (and I have experienced this on many occasions) if you knock out the resonant frequency of a room, you often need to turn up significantly to compensate for that 'weight' having disappeared. Really, these are often between 40 and 80Hz, and if you lose the boost from the resonance you have to compensate somehow.

The result can be the most glorious live sound you can imagine though....

[Adrenochrome]

Cut some bass, boost the low-mids to compensate. Works for me and sounds good through FOH also.

[BOD2]

The "scientific approach" would be to eliminate standing waves or resonant frequencies.

Standing waves are caused when the certain frequencies of sound reflect off surrounding surfaces in phase with the original sound thus reinforcing it and making that frequency louder.

Moving the cabinet on the stage may prevent this from happening - try moving it a foot or so backwards or forwards to see if it makes any difference.

Resonant frequencies have the same effect - the room resonates on certain notes (or harmonics of a note) and makes that notes sound louder. As suggest above a parametric notch filter, set to cut the problem frequency, will help here. If you set the width of the parametric filter to be very narrow it will only cut around the problem frequency and hopefully won't affect the sound too much.

So what frequency would you cut ?

Use a chart like this

[url="http://www.phys.unsw.edu.au/jw/notes.html"]http://www.phys.unsw.edu.au/jw/notes.html[/url]

Figure out which note causes the problem, identify the frequency, and try cutting around that frequency.

It's the same as the suggestions above bit takes a little of the guesswork out of ut.

[alexclaber]

Generally boom lies an octave higher, up in that strange ~150Hz region between the mid-bass and low-mids. Many cabs have more output than ideal there because of being in undersized cabs. Also a lack of excursion limited power handling down low causes extra output to be synthesised in this region when you ask for more true bottom than the cab can provide, hence the misconception that too much bottom equals boom. Clean deep lows are not boomy but not a lot of cabs can produce such lows at high SPL.

Wall reflections can exacerbate boom problems, as can stage/floor resonance. Moving your cab vs the walls can make a huge difference - it's standard practice with hi-fi to try to make the distances between speaker and each wall not only different but also not multiples of each other. Isolating the cab from the floor will stop direct mechanical coupling causing boom but it won't stop the acoustic output causing indirect mechanical coupling.

First thing I'd do is move the cab closer to the walls, and also consider tiliting it towards your ears - midbass boom is much less of a problem if the midrange is clear. Try lifting it onto a beercrate or some foam rubber for a degree of mechanical isolation.

Valve amps are also more likely to suffer from boom if you overdrive them - don't ask for more bottom than the amp/cab combination can cleanly provide.

I have never ever had to fiddle with EQ to get a good sound with my old Acme rig and especially with my Barefaced Big One - both rigs can do tons of deep clean bottom, so things never get boomy - plus good off-axis midrange means you always have plenty of punch and definition even when the acoustics are really challenging. But you have a very nice rig there so if you use it within its limits and use the acoustics in your favour (a valve powered 2x10" can't do big bottom, just too little power and LF sensitivity, so let the boundary reinforcement of the walls help it out) then you should be fine.

A good parametric EQ can be very effective if used correctly but it really does strike me as overkill.

Alex

[stevie]

Moving your cab backwards or forwards a bit is unlikely to do much for a standing wave that is as low as you describe (although you never know with these things). Try turning the cab so that it is not at right angles to the back or front wall. As the others have already mentioned, I'd certainly try dropping the 60-80Hz slider on my graphic, or parametric if I had one.

[Ba55me15ter]

[foal30]

must be a lot of poor cabinet design with smaller than 15" speakers in them then. Commonly would it not be accurate to state that cabinets with 15" or larger drivers handle a low B string better? It may be plop but I'd wager most players wanting the Low B would also consider using 15" speaker as par for the course.

the blanket was more to do with the Original Post. As in the asked for Quick Fix I was not providing in any way


Notch Filter? No, thanks for the tip though. Generally I buy gear that is a nice color, is used by someone famous I like, or in this case, I had room on my pedal board

[Kiwi]

[quote name='alexclaber' post='498695' date='May 27 2009, 12:01 PM']A good parametric EQ can be very effective if used correctly but it really does strike me as overkill.[/quote]
Sometimes people don't have the flexibility to move cabs around if they're on a crowded or small stage, Alex. Parametric eq is also used by every competent sound engineer with access to a mixing desk at a gig.

[Kongo]

[quote name='foal30' post='498495' date='May 27 2009, 08:25 AM']well the Boss PQ-3B is on my pedal board
and I think 5 string bass means 15" speakers.

potentially not as cheap a solution as a blanket under your cabinet though.[/quote]

I run 5 and 6-string through 10" speakers.
More than enough boom on modern 10"'s you don't need size for bass and I'm against some mean de-tuned guitars.

[alexclaber]

[quote name='foal30' post='500553' date='May 29 2009, 07:15 AM']must be a lot of poor cabinet design with smaller than 15" speakers in them then. Commonly would it not be accurate to state that cabinets with 15" or larger drivers handle a low B string better? It may be plop but I'd wager most players wanting the Low B would also consider using 15" speaker as par for the course.[/quote]

And here are the first cabs which were truly designed with 5-string bass and the low B fundamental in mind: [url="http://www.acmebass.com/"]http://www.acmebass.com/[/url]

Note the dearth of fifteens...

Poor cabinet design is an issue though - too many cabs have too much woofer area crammed into too small a box size, which raises the resonance of the system causing a lack of deep lows and an excess of boomy mid-bass.

Alex

[alexclaber]

[quote name='Crazykiwi' post='500557' date='May 29 2009, 07:29 AM']Sometimes people don't have the flexibility to move cabs around if they're on a crowded or small stage, Alex. Parametric eq is also used by every competent sound engineer with access to a mixing desk at a gig.[/quote]

Good points! But I do think that if you use cabs with more true bottom and less reliance on mid-bass boom whilst exhibiting less distortion in the lows, plus good off-axis midrange then you'll never need a parametric EQ. Not a lot of cabs like that though!

Alex

[Kiwi]

[quote name='alexclaber' post='500842' date='May 29 2009, 11:55 AM']Good points! But I do think that if you use cabs with more true bottom and less reliance on mid-bass boom whilst exhibiting less distortion in the lows, plus good off-axis midrange then you'll never need a parametric EQ. Not a lot of cabs like that though! [/quote]
cabs can't compensate for poor stage acoustics or noisy bandmates either.

[Monz]

Ok... just a quick message for those of you thinking of getting an auralex isolation platform... just get one

Is like the best effects pedal ever, if they made one to clean up the sound. I tried it back to back on a solid concrete carpeted floor (without the auralex) then onto a wooden floor suspended on joists with a cellar underneath (with the auralex) and it sounded better on the wooden floor then just to push my luck a little further tried it on the concrete floor with the auralex and yep... better still

I guess this is how mesa boogie valve is supposed to sound

thanks for all your suggestions and advice guys... all very helpful

Will let you know what difference it makes at gigs soon

[alexclaber]

[quote name='Crazykiwi' post='500858' date='May 29 2009, 01:06 PM']cabs can't compensate for poor stage acoustics or noisy bandmates either. [/quote]

Actually, they can. The more even the power response (sum of on and off-axis response in all directions) is, the more consistent the sound will be when the acoustics are poor. Good power response means that even if you're standing in exactly the wrong place you'll still hear a decent sound, even if a huge portion of that sound is reverberant (i.e. reflected from walls, floor, ceiling, furniture, etc) rather than direct. You can't defeat the lower frequency standing waves issues but sort out the midrange power response and humps and troughs in the lows become far less significant.

Alex

[High score]

[quote name='Crazykiwi' post='500557' date='May 29 2009, 07:29 AM']Sometimes people don't have the flexibility to move cabs around if they're on a crowded or small stage, Alex. Parametric eq is also used by every competent sound engineer with access to a mixing desk at a gig.[/quote]


Totally agree. The ability to place gear on stage is more often than not space driven instead of best sound.

Main issue I see is the wooden decking or hollow floor you are playing on. This will create a very low ''rumble'' as certain frquencies resonate so try experimenting with any EQ you have on your amp and lightly cut within the 40-100hz band. If going through a desk, the Sound Man can either use the 80-100Hz pad on his desk (not normally used on bass and little severe) or will certainly exploit the swept EQ available to him by cutting the lower band and possibly slightly increasing the lower mids to place you in the mix. Ideally he will EQ the room for your channel anyway because if the bass rumble is as bad as you say it is, it may swamp the stage sound.

[foal30]

good for you Monz
I love a happy ending

well nearly there I guess, gigging to test etc
score!