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Micrphone placement on bass cabinets


Rocky McDougall

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If you have a bass guitar that is capable of a 50hz tone and you have a speaker cabinet that will produce a 50hz tone out of 4 10" speakers yet one speaker on it's own will only produce a 60hz tone, should the microphone be placed in the center of the 4 speakers instead of directly in front of one speaker. My assumption is that multiple speakers 2, 4 or 8 can produce a lower tone that any one of the single speaker on it's own. I read this on a speaker website, Is it true?

"Democracy is two wolves and a lamb, voting on what to eat for lunch. Liberty is a well-armed lamb, contesting the vote."

Benjamin Franklin

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Experiment.

I had a sound guy that would mic the outside edge of a driver and also mic a port. The blend was incredible.

If you are talking about sound reinforcement you have to take into consideration what freq the mains and monitors are capable of. Can they pump 50hz faithfully? Maybe.

As for the cab putting out a lower freq than the driver is phsically capable of, doesn't make much sense to me no matter how many holes/speakers are in the cab. But I am curious - maybe one of our tech guys will offer some insight.

"He is to music what Stevie Wonder is to photography." getz76

 

I have nothing nice to say so . . .

 

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What microphone?

 

I have never been happy distance micing a bass cabinet.

 

I have experimented, and I find a sweet spot is usually on or near axis with a dynamic microphone 6 to 18 inches away. My favorite mic is still the Electrovoice RE20.

 

If you want to reproduce those low tones, I suggest you also take a DI and blend; remember to match up the signals to account for the delay in the mic line (speed of sound versus speed of light).

 

Others know more than me; I am a hobby guy who has some decent gear and lights to play around.

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Originally posted by mattulator:

Experiment.

 

As for the cab putting out a lower freq than the driver is phsically capable of, doesn't make much sense to me no matter how many holes/speakers are in the cab. But I am curious - maybe one of our tech guys will offer some insight.

The article I read was many years ago but it was about the "Hammond Organ - Living Wall" which was a home speaker system made up of about 48 very small speakers. Each speaker, individually, could only produce something like 100hz lows, but combined, (wired I think in series), Could produce 40hz lows. I think this is the same reason that the Bose 901 series has 18 small drivers. ?????????

:confused:

Rocky

"Democracy is two wolves and a lamb, voting on what to eat for lunch. Liberty is a well-armed lamb, contesting the vote."

Benjamin Franklin

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Alex is 'busy'. I'll have a go though. I would think that individually your speakers can still produce sound down to 0Hz, although the roll off below 60Hz is probably specified in such a way that they perform badly on their own. Putting them together in a cabinet and tuning the ports produces resonance that will help the lower frequencies to come through.

 

Move the mike around and see what sounds best.

Feel the groove internally within your own creativity. - fingertalkin

 

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Originally posted by davio:

Originally posted by Thomas Wilburn:

Produce sound at 0Hz? Don't my speakers do that when I turn them off?

I hear they're putting speakers that can reproduce 0Hz at full volume in the new AccuGrooves. ;):D
ROTF. Actually, it's not the drivers themselves that offer that particular feature...there's a new switch that auto-magically changes the frequency response of the cab...it's called the AccuFreq... ;)

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Rocky...are you recording or miking an amp for a performance? In either case, I think it's really hard to beat using a DI straight into the board or audio interface...unless there's something very specific that you're trying to accomplish.

 

On the drivers...it's probably not so much that the drivers in question *can't* produce 50Hz...they probably can, but it's such a quiet output you don't hear much of it. When you couple multiple similar drivers, then they can move more air and that low frequency signal that you can't hear with one can be heard with 4 drivers.

 

Generally the Fs (free air resonant frequency) of the driver will mark it's useable low frequency extension capability. Putting it into a cab will always push it's resonant frequency higher rather than lower. Download a copy of WinISD (freebie enclosure design program) and do some experimenting.

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Thomas I didn't say 'at 0Hz' I said 'down to 0Hz'.

 

below 16Hz sound is still produced, you just can't hear it, it will just annoy the whales ;) Its whats called infra sound down to about 0.001 Hz

 

Although I doubt that any normal speaker would reproduce faithfully these sounds.

Feel the groove internally within your own creativity. - fingertalkin

 

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I have also wondered why the "Super Subs" that are now all the rage in auto sound systems have not shown up in Bass Cabinets. Some of these speakers are quite elaborate with giant magnets and a tremendous amount of cone travel with all sorts of space age cones and surrounds. I realize that these are just designed to go

"Thump, Thump, Thump" and not really intended to produce real music but I do find them facinating.

Rocky

"Democracy is two wolves and a lamb, voting on what to eat for lunch. Liberty is a well-armed lamb, contesting the vote."

Benjamin Franklin

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Originally posted by Dave Sisk:

Rocky...are you recording or miking an amp for a performance?

Dave

No Dave I was just curious, I realize the DI is the better of the two ways.

 

I did go to the Acme website and looked at their cabinets. They offer a 1 x 10 and 2 x 10 and a 4 x 10 all with the same speaker. They all show a low end of 41 Hz so multiple speakers evidently don't lower the actual response, just the "felt" sound waves.

Rocky

"Democracy is two wolves and a lamb, voting on what to eat for lunch. Liberty is a well-armed lamb, contesting the vote."

Benjamin Franklin

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Originally posted by Rocky3840:

I realize that these are just designed to go

"Thump, Thump, Thump" and not really intended to produce real music but I do find them facinating.

Rocky

I haven't been to enough gigs, or close enough to see, but at this place I went to there were like 3 2x18 subs on each size of the stage, about 4ft-5ft high. On the floor, and they definatly thumped me.

And also produced some bass.

My trousers were moving and my heart was stopping!

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Rocky...yup, all of the Acme cabs are designed to produce the exact same frequency response, regardless of whether it's a 110, 210, or 410. The difference is in the sensitivity of those cabs...how loud they will go on 1 watt of juice (and thus how loud they will go period once you also consider what the maximum wattage is that you can pump through them...generally considered to be about twice their RMS rating).

 

There are three characteristics of any low frequency reproducing cabs...volume (ie. size and weight), sensitivity (how efficient it is and thus how loud it can be pushed), and frequency response (generally, where is it's 0db and -6db points where low frequencies are concerned). You can choose two of those parameters, and the final one is determined for you based on that choice. Most PA sub mfg's want the cabs to have extreme low end extension on the frequency response piece, and they want them to be as efficient as possible...the result is a large and heavy cab (those 218's probably weight 200-300 lbs each or so) and definitely would not fit into a small vehicle. The traditional bass cab mfg's generally shoot for (relatively) small size and weight and high efficiency...the result is a compromise on low-end freqency response...many bass cabs (even some of the big ones, like the revered Ampeg 810)hit their -6db point or even their -10db point (generally consider the lowest relative point of useable amplitude) at somewhere between 60-100 Hz, quite far from the 40 Hz of a low E or the 31 Hz of a low B. The Acme's are designed to hit their -6db point at 31 Hz (a low B, thus the name) and be (relatively) compact and light, in line with other bass cabs...the downside is that they are quite inefficient and need gobs of amplifier power to sound good. I run my LowB4 off of a 3000 watt QSC PLX-3002, but have the levels set so that the cab should see no more than about 1500-1600 watts. Just to see, I did crank it once to the point that the clip LED's on the power amp would barely blink (meaning the cab was seeing the full 3000 watts on peaks but likely only seeing 300-600 watts on the average)...I can definitely say with confidence that it can shake pictures off the walls of my house (and it's not a small house) without the drivers even thinking about farting out. However, I wouldn't run it to that extreme in more than a short experimental sense...that would qualify as asking for thermal damage to the driver voice-coils. If I actually needed to be that loud, I would add another cab.

 

Interestingly enough, we are generally so "not used" to hearing/feeling the actual 31 Hz of a low B or even the 40Hz of a low E that I find I cut some lows and boost some mids in my signal when using that rig. You'd really be surprised how lows are actually in a bass guitar's output...we usually just don't have gear the monstrous gear that can actually reproduce all those lows accurately.

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Originally posted by Dave Sisk:

ROTF. Actually, it's not the drivers themselves that offer that particular feature...there's a new switch that auto-magically changes the frequency response of the cab...it's called the AccuFreq... ;)

 

Dave

Yeowza...I didn't even mean to dredge that up. Maybe would've been better off saying the new Eden's were doing it. :freak:

 

Either way it's funny I guess.

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