Cab's Low Freq Response for Good B String?

Lot's of discussion on this if you do a search. Some great posts by the EE's on the site. Here's my take on it from participating in a lot of those threads:

Assuming the published spec is accurate (or even if it's not), you won't hear a 'cut off' at all. You will just hear more of the second harmonic (if I have that correct... I believe the fundamental 31hz open B is called the first harmonic... but you know what I mean) than the fundamental of the lowest notes on your instrument.

Many of us hear the second harmonic of the open B string as a 'punchy and tight' tone versus the true 30hz fundamental tone.

The key to a 'good' B string sound IMO is having enough power and a large enough cabinet to move enough air into the audience. A very small cab tuned very low (40hz) is going to sound beautiful on the low notes at very low volume, but just die as you turn it up. However, a cab like, for example, the Eden410XLT that has quite a high -3db roll-off, can produce a stunningly good, punchy, loud B string tone that can punch through to the back of the room with a moderate amount of power.

Also, the published -3db roll-off spec, even assuming it's accurate (which many times is not the case) is not the whole story. Cabs can sound quite different based on the slope of the roll-off below that published -3db spec... some drop like a rock, and others more gently roll off.

So, IMO, in a small cab like a 210, a somewhat higher -3db rolloff can actually result in a louder, tighter, more functional B string tone that doesn't require a zillion watts and multiple cabs to project out into the room. It won't give you the 'fundamental' ash tray shaking tone, but that often times gets in the way of a mix anyway (depending on your playing context).

 

nice rply there KJUNG



what do u think of a schroeder 410R ? with a 5 string

 

Thanks! I think it's pretty close to being accurate. The EE wizzes will fix up any places I skuffled through!

Edit: The 410L is a wonderful example, IMO, of what I was talking about.... relatively high roll-off, but a B that will just punch you in the chest with 500 or so watts IMO and IME. I actually like the low end of the cab better than the upper mids and treble... but that's another subject!

 

Dont forget that what the cab is tuned to is not the lowest frequency it can produce.
It simply indicates that the speaker/s in it requires it to be tuned to resonate at that frequency to extend the range of the speaker. the speaker itself can have lower frequency or higher then what the cab is tuned to resonate at.

Pretty technical stuff to explain, but even though it is true that tuned frq. suggests its lowest frequency at 0 or minus 3db it is not the lowest note it will produce.

The biggest thing with low"B" I find is effeciency and power management. 30-32Hz is a pretty low stuff it needs tons more power to be fully audible as well as a substantial hump in the low end cab response. Feeding that load into one speaker even if it is 15 or 18" is a huge amount of motion for the cone, may be contrary to some views, I find it is better to split wetween number of drivers like 4 10's or similar to tighten effeciency and power handling.

Well I got sidetracked, but yes you absolutely can get good low b sound out of 2 10's but not at a huge volumes. Just like Kjung said the responce slope is more important then published low ext.

 

KJungs response in post 2 answered it pretty well. There are VERY few cabs out there capable of even a -3dB point near 30Hz so the majority of what's being heard is the second harmonic.

 

A 212 over a 410 (IME) for a single-cab setup is more favorable (to my ears), as 5+'s are all I play.

But the Schro 410R I had handled my Q5's B string quite well. Other 10's, not so much.

 

It's pretty difficult to get a cabinet that people are willing to live with that will provide good frequency response down into the range of the B fundamental (31 Hz). You wind up requiring very large speakers. It pretty much comes down to Hoffman's Iron law (you can have low end extension, high efficiency or small enclosure size... pick two). I've been working on a design on and off over the past few months for a couple of bass cabs, one of which is a subwoofer cab that will have an f3 of about 30 Hz. The problem is that compared to the mid/high cab, the subwoofer cab needs to be about 4 times as large and uses 2 high excursion 12" drivers to match the output of the single 12" in the mid/high cabinet.

It's obviously not necessary to have a -3 dB point in the 30 Hz range for a 5 string bass to sound good. I've used cabs that certainly don't have much for response below 40 Hz with 6 string basses and the Bs have sounded great. I've heard lots of bands where the bass player doesn't have response to anywhere near 30 Hz with a 5 string bass and they've sounded good. I would like to play through a truly full range system with basses. The sacrifice is size.

 

Actually, per the 'two out of three' above, you can have low and small... just with a lack of efficiency. The Acme cabs are tiny, and really do go ALL THE WAY down there! They do take a bunch of power, but if you are looking for close to a low B fundamental frequency response, they do a good job. Of course, you need at least a couple of 210's to project any kind of volume into the audience, but it does work.

That being said, per my previous post and your comments, having a cab that goes down that low is not necessarily a good thing. But they are quite a unique line of cabs, and for certain applications, they sound quite amazing.

 

Agreed to the last two.

It's nice in theory to say "My cab can handle a full low B down to 30hz!" (trust me, I've been on this quest w/ cash and credit cards in hand), but in a live situation, esp with a PA and subs, it's not that practical. Your cab is the last thing in the mix they'll hear with a 10,000W FOH setup.

That's why you get your full range signal from your DI, pushing to the FOH's (which usually can do the 30-35hz thing properly), and then you mike up to get your top end and drive.

 

Not commenting on the Acme's in particular, but drivers suffer from power compression, so usually around half their rated power and you won't get any more out of them; eg the Beyma 15G40 shows a free air power compression of 3dB at 400W (rated at 700W), so more power doesn't mean an increase in SPL, but the driver won't be damaged. In reality, it would be at a lower power level as the driver is enclosed in a box with no effective means of shedding the heat.

 

Well, yeah... pick two. Using inefficient drivers can be ok if they can handle a lot of power and do not suffer so much from power compression that the extra thermal power handling is useless.

I don't know that it's necessarily a bad thing either. It's a trade off.

 

Even though I've got the EE paper from 1989 and a semester in acoustics(NICE elective!), what gets used for gigging depends on the place. MOST gigs are using the BOSE PAS which cuts off bigtime at 40 Hz(on paper, my ears say it starts falling at the C note on the A string, 65.41 Hz). I also have ACME's and an 8 x 8 SWR Henry. The PRIMARY difference with all of them:

If the cab CAN produce the low B fundmental you FEEL the B string.
If the cab cannot actually go that low, you mind will "hear" it via harmonics.

I prefer the FEEL but can trade it for convenience(i.e. BOSE vs ACME) at times if the overall band sound doesn't suffer.

Reference chart here: http://www.contrabass.com/pages/frequency.html