And here we are back at the fact that driver size only tells you driver size. Don't get all internet-tough guy and then arrive in agreement with me.
Enjoy the benefits of a premium membership!
Upgrade Account
-
Welcome to TalkBass! Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Acme B-112 vs Barefaced Big Baby
- Thread starter Doner Designs
- Start date
And here we are back at the fact that driver size only tells you driver size. Don't get all internet-tough guy and then arrive in agreement with me.
nope, cause there are drivers meant for low (sub) aplication and those for low/mid applications.
Two families of drivers which should give appropriate respect at driver choice.
I hate to talk about one is way better than the other, but there are trade offs to consider. A tube head may be an essential criteria if one of both famalies fits better to personal taste.
Knew a HiFi salesperson that lived around Dallas back in the day.
Owned a pair of E-V Patrician 800 speaker cabs (315 lbs ea.) with a 30" woofer.
It would shake the walls with a 60W/ch. amp.
Owned a pair of E-V Patrician 800 speaker cabs (315 lbs ea.) with a 30" woofer.
It would shake the walls with a 60W/ch. amp.
- Jun 2, 2012
- 5,769
- 6,761
- 4,961
- Disclosures
- Doner Designs is an alias for Steve Doner
Are there any rules of thumb that a person can use to estimate the output at lower frequencies? I'm guessing not because it would depend on how steep the rolloff curve is but it doesn't hurt to ask. In other words, if a maker says -1db at 50hz, can I make an educated guess at the -3, -6 and -10 db points?
alexclaber
Commercial User
- Jun 19, 2001
- 5,189
- 2,744
- 4,921
- Disclosures
- Director - Barefaced Ltd
No. For three reasons:
1. You don't know the shape or slope of the roll-off curve of the cab.
2. You don't know the shape or slope of the roll-off curve of the amp post EQ.
3. You don't know the excursion limited power handling curve.
Unfortunately, again--- most cab makers don't supply information as far as the slope of the curve. Which thay can--but for some inexplicable reason choose not to. If one knows the Vd (amount of air displaced) and -3db and -10db points one can make an educated guess as far as volume and low frequency extension. Again---this is just a starting point--but you are approaching the realm of apples-to-apples comparison.
Again--low frequency claims without -3db and -6db points are marketing---not an accurate indicator. Alex does include Vd in his literature (using a bit different yardstick), as do Duke and I. It's a good starting point to compare the amount of air a cab can move.
- Dec 3, 2003
- 21,505
- 40,665
- 6,351
- Disclosures
- Designer/Toaster Tech @ Passinwind Electronics
Sure, an educated guess means taking the cynic's viewpoint: take whatever "they" say the -3 dB point is (or often just don't specify) and substitute -10. Assume the worst, rejoice if things are a little better. Done.
If you want to get all the way into this rabbit hole you might want to bone up on venue boundary conditions, which matter quite a lot.
Last edited:
- Nov 24, 2008
- 4,343
- 7,120
- 4,986
- Disclosures
- Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
Imo you'd have to model the cabinet using a box design program in order to make an educated guess about what the shape of a cabinet's low-end frequency response looks like, and that in turn could require you to make guesstimates about the woofer's parameters and/or box tuning frequency. This will work for sealed and vented boxes. To the best of my knowledge there are no programs available that will predict the response of Mike Arnopol's MVW bass cabs, but based on my experience with some of his cabs and my own MVW prototypes (for the home audio market), and based on what I know about Mike, I have confidence in his claims.
You can assume competent design for any bass cab on the market, even if the shape of their low-end response curves differ somewhat. So here is something you might find useful in making comparisons between two cabs of similar design (two sealed cabs, or two vented cabs): In order to increase the efficiency by 3 dB, you either have to double the box size or give up 1/3 octave of bass extension. Or, conversely, if you want to increase your bass extension by 1/3 octave, you can either double your cab size or trade off 3 dB of efficiency. So, in order for one cab to go an octave deeper than another cab, it will either be 8 times as large, or 9 dB less efficient, or (more likely) some combination thereof.
An optimized vented box will have a -3 dB point approximately 1/3 octave deeper than an optimized sealed box of the same size and efficiency. The sealed box will have a more gentle rolloff south of the -3 dB point. If you use the same woofer in both boxes, the difference will be greater, like closer to 2/3 octave or more.
In practice these relationships may not be exact, but they will be in the ballpark.
The shape of the low-frequency response curve matters more than you might think, because of the characeristics of human hearing a low frequencies. If you look at a set of equal-loudness curves, you will notice they tend to be closer together south of 100 Hz or so:
What this means is, changes in SPL at low frequencies make disproportionately large changes in perceived loudness. So the shape of the low-end response curve matters a lot, for better or for worse. This is why a delicate touch is needed when dialing in low-end EQ - a small change can make a big difference.
And as Passinwind brought up, the room matters too! At low frequencies, cab + room = a system. So as you have no doubt noticed, what works well in one room can totally suck in the next, so you have to do things differently in that next room.
Last edited:
- Jun 2, 2012
- 5,769
- 6,761
- 4,961
- Disclosures
- Doner Designs is an alias for Steve Doner
We have drifted quite a ways from the original question, but that's just fine with me. Lots of interesting info flowing here!
Have any of you builders ever seen or considered doing a vented cab that has a collapsible tail for a port? I built a labyrinth cab for my home audio system when I was in high school but the box was enormous. What about taking a small cube to mount the driver and then use something like expandable clothes dryer vent hose to give it a 6 foot port (or whatever is optimal) which can be bunched up for travel and storage. Might be too weird for mass marketing, but it could be perfect for some of us crazy old men.
One other question - does box size matter as much in a sealed cab? I get that it's part of port tuning when the cab is vented. With a sealed cab, the smaller the volume the more the internal air will dampen/reduce the excursion, but maybe that can be overcome by driver design?
Have any of you builders ever seen or considered doing a vented cab that has a collapsible tail for a port? I built a labyrinth cab for my home audio system when I was in high school but the box was enormous. What about taking a small cube to mount the driver and then use something like expandable clothes dryer vent hose to give it a 6 foot port (or whatever is optimal) which can be bunched up for travel and storage. Might be too weird for mass marketing, but it could be perfect for some of us crazy old men.
One other question - does box size matter as much in a sealed cab? I get that it's part of port tuning when the cab is vented. With a sealed cab, the smaller the volume the more the internal air will dampen/reduce the excursion, but maybe that can be overcome by driver design?
- Nov 24, 2008
- 4,343
- 7,120
- 4,986
- Disclosures
- Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
I've used variable-length ports in home audio, but not a collapsible "tail". I use pluggable ports in my bass cabs (as well as in home audio) to give some user adjustability, which can theoretically be helpful in a boomy room.
A clothes dryer vent would not have sufficiently rigid walls in my opinion, but the same idea in a hard plastic might work. Friction losses might be high, reducing the magnitude of the port or line's contribution.
You mentioned building labyrinth home audio speakers when you were in high school - very cool! I built my first pair of "transmission line" (fancy name for "labyrinth") speakers a year after high school. I had to assemble them in my upstairs room because they would not fit up the stairway. When I was ready to get rid of them and build something else, I had to throw them out the window, for the same reason. Practicality was not very high on my priority list.
You are correct, box size makes a much bigger difference (for a given woofer) with a vented cab than with a sealed cab. But imo you don't want to shrink the box size too much with a sealed cab, because you do lose low end, and the cab can start to sound "wooly".
By using a heavy cone, long-excursion woofer with a very powerful motor, and accepting the efficiency tradeoffs, it is possible to get really nice deep bass from a small sealed box. This is the approach many home audio subwoofer manufacturers use. But along with the low efficiency, they also trade off any hope of decent midrange along the way, so this approach isn't really practical for a bass cab.
- Jun 2, 2012
- 5,769
- 6,761
- 4,961
- Disclosures
- Doner Designs is an alias for Steve Doner
Watching TV with my wife last night I cracked up at your "throw it out the window" comment!
Just catching up on this thread. I thought this was obvious, but some of the posts make it clear that it's not. The sensitivity of a driver (and speaker system) depends on frequency. It should be intuitively obvious that a big cabinet with a big driver is going to have a higher sensitivity at the lower frequencies. Is that not obvious? So isn't it obvious that a smaller driver/cab requires more power to get a given output at the lower frequencies? Maybe I'm just talking out of my hat. What do y'all mean when you say "driver size doesn't matter"?
Driver size only tells you the driver size. Any assumption that it is in a bigger box is an assumption. That assumption may be generally accurate because big things need to fit in bigger things, but there's the cab volume to consider. Cone size tells you two dimensions, but ignores the third. Displacement is a volume measurement, whereas cone size only gives you area. Discounting the excursion of the driver is nearsighted and an over simplification. The minimum height and width to fit a 15" woofer is obviously bigger than what is needed for a 10" woofer. However, it says zero about the depth of the cab. You could create a small driver with massive excursion which would out perform a bigger driver with a minute excursion.
"Bigger speakers are louder and lower" is based on how speakers used to be designed. It is 2016, let's think like it.
Duke had a great post a bit back where he hit on many of the assumptions and "all else being equal" requirements for rules of thumb to work, and the fact that "all else being equal" is never the case.
...and regarding sensitivity and frequency. I've owned a Barefaced Super Midget and Super Compact. Alex will tell you these cabs are equally loud. I'll tell you the Super Compact sure sounds louder. It's a bigger box and presents lows differently. If you're measuring a sensitivity at a frequency, I'd say the low end sensitivity is better. Measurements and perceptions are tricky.
Last edited:
Well of course, assuming those "all else being equal" things. I think I'm failing to make my point
Edit: Also, I didn't say I was ignoring excursion. To me that's one of the "obvious" things that is covered under "all else being equal".
Edit: Also, I didn't say I was ignoring excursion. To me that's one of the "obvious" things that is covered under "all else being equal".
Last edited:
I wasn't saying you necessarily ignored it. I think many do, though.
It means nothing but comparing apples to oranges does not matter cause both may have same diameter.
It's the same like horse power means nothing but horse power, actually nobody would assemble a Ferrari engine into a truck as well nobody would assemble a truck engine into a Ferrari allthough horse power is the same.
Similar thing is with driver size which means nothing, but there are drivers designed for guitar application and there are drivers designed to work well fo sub application.
Nobody would try to assemble a low-driver into a guitar cab as well nobody tries to assemble a guitar driver into pro PA sub.
If application is narrowed down THEN driver size still matters. Like with different engines for different applications (racing, general purpose, heavy-duty trucking) there are different driver designs for different applications available.
And there has nothing changed to physics/science rules since the first driver was ever built around hundred years before.
And, radiation impedance of a driver can't be improved by shrinking cone diameter.
With bass cabs there are essential different designs. There are cabs loaded with drivers running full range and those loaded with low-drivers which then demand support of an additional cone/device for mids.
Within a "narrowed" cab family driver size still matters, but if comparing apples to oranges it does not matter such a lot.
Btw, regarding pure moved "air volume" numbers of a driver I'm little sceptical with SPL considerations cause lowish tuning can easily eat up impressive Xmax.
At the other hand as long as there is no underrun more than 1/3 below driver thermal ratings, so what!
Last edited:
alexclaber
Commercial User
- Jun 19, 2001
- 5,189
- 2,744
- 4,921
- Disclosures
- Director - Barefaced Ltd
But that isn't quite correct because it depends on how big you're talking about - driver sizes don't vary that much in the world of bass but enclosure sizes vary a lot. Generally a big cab with a smaller driver will have higher sensitivity at lower frequencies than an equally large cab but with a larger driver and definitely than a smaller cab with a larger driver.
And with respect to this it's the total driver area that defines whether it's a 'big' driver or not - so if you have a 1x12" and 2x12" of equal sizes the 1x12" will have higher sensitivity at low frequencies.
So to sum up, bigger cabs have greater LF sensitivity.
That's not quite the argument I was trying to make, but I'll stand corrected. I want to change my argument to "I like big drivers" 
Agree that cab size makes more difference to low response than driver size.
At the other hand within a family of drivers those with bigger diameter "demand" larger cab volume anyway just to compare apples to apples.
For example if a cab is rather large in relation to driver specs than the benefit of lower low-response and way better efficience comes "naturally" along with the bigger diameter (which naturally demands bigger cab size).
Clearly for an equal cab size lots of smallish drivers can outperform the bigger diameter cones regarding low response cause the cab size then is (often) to small to get best results with driver specs of the larger cone diameter.
same net cab volume for both
white: 3015LF /F3=66Hz
yellow: 3010LF /F3=43Hz
For the 3010LF xellow the net volume seems a little to big while for 3015LF yellow the net volume is to small.
The crappy "average" efficience tells a lot about how the 3010LF gets pretty good low-response.
max acoustic power
the smallish cone can't compete with the large cone.
The noticeable valley around 50..100Hz also tells that for the 3010LF net volume should be smaller while tuning somewhat higher
For the record, I compared apples to oranges in this case!
At the other hand within a family of drivers those with bigger diameter "demand" larger cab volume anyway just to compare apples to apples.
For example if a cab is rather large in relation to driver specs than the benefit of lower low-response and way better efficience comes "naturally" along with the bigger diameter (which naturally demands bigger cab size).
Clearly for an equal cab size lots of smallish drivers can outperform the bigger diameter cones regarding low response cause the cab size then is (often) to small to get best results with driver specs of the larger cone diameter.
same net cab volume for both
white: 3015LF /F3=66Hz
yellow: 3010LF /F3=43Hz
For the 3010LF xellow the net volume seems a little to big while for 3015LF yellow the net volume is to small.
The crappy "average" efficience tells a lot about how the 3010LF gets pretty good low-response.
max acoustic power
the smallish cone can't compete with the large cone.
The noticeable valley around 50..100Hz also tells that for the 3010LF net volume should be smaller while tuning somewhat higher
For the record, I compared apples to oranges in this case!
More practical considerations, same net volume both cabs,
most hated combination 410+115
white 115 3015LF /F3=44Hz, Fb=45Hz
yellow 410 3010LF /F3=51Hz, Fb=48Hz
normalized response
SPL 1 watt input power
BTW group delay looks perfect for "matching"
most hated combination 410+115
white 115 3015LF /F3=44Hz, Fb=45Hz
yellow 410 3010LF /F3=51Hz, Fb=48Hz
normalized response
SPL 1 watt input power
BTW group delay looks perfect for "matching"
Last edited: