Sub bass question

[Tom]

Just a quick question about sub bass.

Just been thinking and thought about this but not to sure if it would work or not.


If I was to turn the volume on down my sub, could I then eq the sub to get a deeper sound from it???

The reason I ask is that at some gigs where I dont need the volume, I could get some more depth from the cab.

Would or could it work???

[Bouncy Dancefloor]

such an open ended question

it all depends on what your sub is capable of, what the size of the driver is and therefore what frequencies it is capable of

[Danieleastwood.com]

I agree with Pete here. The cab will have a certain eq curve already from it's design. And although you can eq it, you'll never be able to cheat physics and get frequencies out of a box that it cant do.

E.g: Say a cabinet can produce,at it's lowest, 44hz. It would be pointless to have any faders below that frequency on the eq 'boosted'. This would only give your amp more work to do than necessary, and in certain cases (mainly during raised volume) could start causing square waves, meaning the driver in your speaker wont go back and forth smoothly, It'll be pushed all the way to it's end stops and overheat. (but that is in extreme case)

I learned that one the hard way, many years ago!!!!

[Andy Westcott]

Tom - an interesting question, and in essence you are correct in your assumption.

A 'tuned box' has a response which rolls off at 12dB per octave below port tuning, and at these frequencies there is little loading on the diaphram therefore there is a tendency for the speaker to move too much, risking physical damage. However, as you are intending to drop the volume anyhow, damage would probably be avoided if you are sensible.

To do this successfully you would need a real horse of a speaker, not some cheapy thing, to be fairly certain of getting away with it at fairly high volumes but to be safe, keep those volumes down if you do boost below 40Hz or so.

The best bet of course is to get a sub capable of the results you'd like, but this would be fairly large and expensive.

[Tom]

The sub I am talking about is the DB Sub 15.

From the manual, it can handle from 40hz up to 120hz. Now, I run the sub off a seperate channel on the mixer from the main outs so have full control.

I understand a little bit about speaker cabs. Everybody wants a cab which is small, loud and efficient. You are only allowed 2 of these. That's as much as I know about that really. In my case its small and loud.

My plan was to run a digital eq (1U) and somehow boost the 40-60hz for example without causing distortion or extra stress on the driver. With this I was going to turn down the volume to compensate.

Now my other question about this is would I get a better, deeper sound from the cab that is lower in volume with boosted EQ, or running the cab flat eq and at a louder output???

[pagan_flame]

I have a single dB Tech Sub 15 - I run a flat EQ at the bottom end from a full range output and let the cab's active internals do the rest. Up top I push in the Low Cut button on the SRM 450's, which produces a very good sound that I am totally happy with - this was all set up for me by a sound engineer at my local PA hire shop.

But you're forgetting the crossover switch? I have mine set to 100Hz to match the top cabs, but taking it down to 80 will emphasise the lower sub frequencies but cut off the higher end. Which brings me to...

... It also is affected by the music you are playing; Low E on a 4 string bass is usually about 40Hz, a kick drum between 60 and 100 Hz... but if you are playing electronically generated music, the bass can be much lower of course, producing the 20 - 40Hz thumping that you hear from your neighbourhood chav as he rolls in his bitchin' ride / Nova / Corsa / Saxo / Clio. :Censored:

Hence - 50's Rock 'n Roll will have you checking to see if the thing is switched on, whereas some grindin' R 'n B will have you looking to see if the clip light is on... ;)

[Tom]

But you're forgetting the crossover switch? I have mine set to 100Hz to match the top cabs, but taking it down to 80 will emphasise the lower sub frequencies but cut off the higher end. Which brings me to...

I also hae mine set on 100hz. Just sounds best to be honest.


... It also is affected by the music you are playing; Low E on a 4 string bass is usually about 40Hz, a kick drum between 60 and 100 Hz... but if you are playing electronically generated music, the bass can be much lower of course, producing the 20 - 40Hz thumping that you hear from your neighbourhood chav as he rolls in his bitchin' ride / Nova / Corsa / Saxo / Clio. :Censored:

Hence - 50's Rock 'n Roll will have you checking to see if the thing is switched on, whereas some grindin' R 'n B will have you looking to see if the clip light is on... ;)

Most of my gigs I am playing quite a lot of chart music where it has a lot of synth bass.

This is why I asked the question about lowering the volume and eq the sub.

[nigelwright7557]

Just a quick question about sub bass.

Just been thinking and thought about this but not to sure if it would work or not.


If I was to turn the volume on down my sub, could I then eq the sub to get a deeper sound from it???

Would or could it work???

It would work coz that is precisely how active speakers work.
They eq before the amp so you dont need a crossover.

[Tom]

I think I'll give this a go and if it don't work then Ill buy a new sub.

[Tony Scott]

Most professional active subs have a steep high-pass filter fitted as standard.

A high pass filter will prevent any frequencies below the design frequency of the cabinet getting through, this means that no matter what programme you give the sub it wont reproduce frequencies lower than it's design spec. (40hz for a DB15)..........if you want proper sub then go for something designed to produce 35hz or less!

My subs are loaded with 18"-PD1850's http://www.precisiondevices.co.uk/ShowDetails.asp?id=15
I use a digital LMS with a high-pass filter set at 32hz to prevent the driver from unloading and over exerting below the cabinet design frequency........

......32hz feels good, especially on D&B, Dubstep, RnB etc !!!! :)

[Tom]

Most professional active subs have a steep high-pass filter fitted as standard.

A high pass filter will prevent any frequencies below the design frequency of the cabinet getting through, this means that no matter what programme you give the sub it wont reproduce frequencies lower than it's design spec. (40hz for a DB15)..........if you want proper sub then go for something designed to produce 35hz or less!

My subs are loaded with 18"-PD1850's http://www.precisiondevices.co.uk/ShowDetails.asp?id=15
I use a digital LMS with a high-pass filter set at 32hz to prevent the driver from unloading and over exerting below the cabinet design frequency........

......32hz feels good, especially on D&B, Dubstep, RnB etc !!!! :)


Thanks for that, Tony. :)


Infact, I have been asking questions about using a void speaker for a cab. It's a good idea but the cab will need somthing like 240 litre cab for it to work correctly. I think the most I could fit in my car would be 200 litre max.

That PD1850 is supossed to be quite something in a reflex cab as those drivers are mostly used in horn applications. lol. Same as the void really.

I was recommended the PD186 for a reflex cab but not to sure if its going to have the "punchy-ness" I need as well as going for those o so low notes. Will need to do some testing with WINISD and see what that can some up with.

I think selfbuild sub will be the best opition for bass anyway. It's a lot cheaper than buying a brand name that would have less power within my price range.