Frequency response

[2strings2frets]

What is the practical application of a listed frequency response for a speaker or bass cab? I have seen listed response’s as high as 80 for a bass cab when the frequency of a E string is half of that and a B string is even lower, how is this number to be used? Thanks.

 

[basscooker]

The second harmonic is much more audible than the fundamental; and reproducing frequencies down as low as, for example the low E and B, requires a lot of power and can stress drivers too much at high volumes. You really wouldn't want (generally speaking) a bass cab that is flat down there. -3 dB at 80 is not bad at all.

 

[Redbrangus]

how is this number to be used?

In the absence of other qualifying information, frequency response numbers are pretty much meaningless. Some manufacturers might use the -3dB point; others might cite the -10dB point. Still others seem to just pull numbers out of their... uh ... out of thin air. And almost without exception, those frequency response numbers are at 1 watt, not at the rated power. Even with some qualifications given, I wouldn't assign much value to those numbers except to compare models within one manufacturer's product line. Otherwise, it's mostly all just "Fun With Numbers" and marketing puffery.

As far as NEEDING flat response down to 40 or even 30Hz -- that's a whole different can of worms. Whether or not that's critical to the sound of a bass amplification system has been the subject of quite some discussion in these parts. All I want to say about it is to go search out some of those threads on your own.

 

[2strings2frets]

In the absence of other qualifying information, frequency response numbers are pretty much meaningless. Some manufacturers might use the -3dB point; others might cite the -10dB point. Still others seem to just pull numbers out of their... uh ... out of thin air. And almost without exception, those frequency response numbers are at 1 watt, not at the rated power. Even with some qualifications given, I wouldn't assign much value to those numbers except to compare models within one manufacturer's product line. Otherwise, it's all just "Fun With Numbers" and marketing puffery.

As far as NEEDING flat response down to 40 or even 30Hz -- that's a whole different can of worms. Whether or not that's critical to the sound of a bass amplification system has been the subject of quite some discussion in these parts. All I want to say about it is to go search out some of those threads on your own.

Thank you

 

[2strings2frets]

Tha

The second harmonic is much more audible than the fundamental; and reproducing frequencies down as low as, for example the low E and B, requires a lot of power and can stress drivers too much at high volumes. You really wouldn't want (generally speaking) a bass cab that is flat down there. -3 dB at 80 is not bad at all.

nk you

 

[WayneP]

A few years back I took some on-axis in-room measurements of a couple of cabinets that I had on hand, a Genzler BA12-3 and an Aguliar GS-112, both two-way cabinets with 12” woofers. You can see the results in the graph below (smoothed 1/3-octave) – Genz is the red trace, Aggie is the green. Aguilar spec’s the GS-112 at 42Hz-16 kHz +/- 2 dB, while Genzler spec’s the BA12 as 35Hz-15kHz (no +/- figure). You can see that both cabinets fall like a brick below 80 Hz, and 4 kHz, octaves short of their published specs.

So yeah – what @Redbrangus said.

Anyone desiring to generate the low fundamentals of the E and B strings, it usually requires a separate subwoofer, low-passed to roll in where the main cabinet rolls out. Is it necessary? Of course not – you can hear the lowest notes on a bass just fine with virtually any cabinet on the market. But it’s certainly enjoyable to have.

Regards,
Wayne A. Pflughaupt

Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Official Tobias Club #133
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Pedulla Club #45

 

[J Wilson]

As the other guys have pointed out, bringing up the fundamental (the 43.5hz E and the 31hz low B) is a much bigger engineering challenge entailing far more power, far bigger cabinets . . . . and far more money. This ain't gonna happen with a Katana Bass or Rumble combo. Making those notes is big boy touring sound territory.

But the good news is that what we hear and consider 'bassy' is the harmonics doubling up from those root frequencies. So for most bass rigs the 100 and 200hz sliders is what we think as deep bass. Letting the fundamentals roll off saves the day and the budget and still makes noise like a good bass amp.

IF you really want honest specs in bass cabinets, go to Mesa's website and see the posted specs for each of the Subway cabinets, or for a broader range more upmarket, go to Bag End's web page and read the specs for anything you decide to check out.

As @agedhorse points out, currently there are no regulations regarding everyone running the same tests where the published results could comparatively yardstick Cab A to Cab B, and you rarely see anything meaningful or honest specs regarding bass cabinet performance (or amplifiers either) from most of the majors.

Here's the specs and description for Bag End's S-15XN, their take on a single 15 with their concentric Hi-Drive to flesh out the high end (instead of the more normal tweeter or small compression driver)

S15X-N.pdf (bagend.com)

And the similar 15"+high end format from Mesa in the Subway Ultra Light line, the Subway 115:

Mesa/Boogie | 1x15 Subway Bass (mesaboogie.com)

Cruise around other manufacturer's websites, and this kind of info is unfortunately scarce or nonexistent.

 

[GregT]

The only bass amp I've ever seen that might have been producing the fundamental of a low E was a vintage Blonde Fender Bassman into a giant folded horn lying on its side. It had two 15 inch speakers inside facing backward and it took 3 or 4 people to bring it into the club. It was also the best live bass tone I have ever heard in my life. However, I'll stick with my Rumble 200.

 

[agedhorse]

A few years back I took some on-axis in-room measurements of a couple of cabinets that I had on hand, a Genzler BA12-3 and an Aguliar GS-112, both two-way cabinets with 12” woofers. You can see the results in the graph below (smoothed 1/3-octave) – Genz is the red trace, Aggie is the green. Aguilar spec’s the GS-112 at 42Hz-16 kHz +/- 2 dB, while Genzler spec’s the BA12 as 35Hz-15kHz (no +/- figure). You can see that both cabinets fall like a brick below 80 Hz, and 4 kHz, octaves short of their published specs.

So yeah – what @Redbrangus said.

Anyone desiring to generate the low fundamentals of the E and B strings, it usually requires a separate subwoofer, low-passed to roll in where the main cabinet rolls out. Is it necessary? Of course not – you can hear the lowest notes on a bass just fine with virtually any cabinet on the market. But it’s certainly enjoyable to have.

Regards,
Wayne A. Pflughaupt

Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Official Tobias Club #133
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Pedulla Club #45

View attachment 4860704

If you are going to accuse manufacturers of being dishonest, you should understand how gross inaccuracies in your measurements and their interpretation might contribute to your erroneous conclusions.

1. The red curve data reads as: F3=60Hz, F6=55Hz and F10=50Hz

2. The green curve data reads as: F3=55, F6=35Hz and F10=30Hz

In both cases your own data doesn’t support your conclusion.

Now for your data, the shapes of the curves indicate that these measurements include boundary interference which make the data inaccurate for comparison. Anechoic measurements that do not contain boundary artifacts, have a different LF shape than your curves.

Making accurate and consistent acoustic measurements is challenging under ideal conditions, and virtually impossible under typical room conditions. Making measurements and making accurate measurements are completely different things.

Accusing somebody (2 different manufacturers in this case) of being dishonest based on your defective measurements AND your inaccurate conclusions (fall like a rock below 80Hz) base on those same graphs, is unfair to both of those manufacturers.

 

[micguy]

You really wouldn't want (generally speaking) a bass cab that is flat down there. -3 dB at 80 is not bad at all.

The real reason you don' t want a bass cab that is flat to 40 (or 30) Hz is that it won't fit in your car. There is a myth that somehow having that bandwidth would be a bad thing - it isn't. The audio performance of such a cabinet is a big plus - I do ampless gigs, where I'm heard through subs that are flat to 30 Hz (I play 5'ers). The difference in impact from those versus a cab that only goes down to 80 Hz is stunning. And no, it isn' t muddy - mud comes from overdriving a cabinet that can't reproduce low frequency fundamentals - asking it to do what it can't.

A low B through a rig that reproduces it well is a wonderful thing.

 

[JeezyMcNuggles]

What is the practical application of a listed frequency response for a speaker or bass cab? I have seen listed response’s as high as 80 for a bass cab when the frequency of a E string is half of that and a B string is even lower, how is this number to be used? Thanks.

Subwoofers crossover at around 100.

Bass cabs, are not subwoofers.

Low E's fundamental is 40hz. If that was all you heard when you hit an E, you'd never hear the bass player. As opposed to, usually can't hear the bass player.

 

[micguy]

A few years back I took some on-axis in-room measurements of a couple of cabinets that I had on hand,

If you are going to accuse manufacturers of being dishonest, you should understand how gross inaccuracies in your measurements and their interpretation might contribute to your erroneous conclusions.

I made my living for over 4 decades in part designing and building acoustical stuff - mostly microphones, but also loudspeakers. If you think you can do accurate acoustical testing at home, you are mistaken. The kind of gear you need to do that includes a purpose built anechoic room, a whole lot of B&K equipment, and a LOT of schooling to understand what you are doing.

 

[agedhorse]

I made my living for over 4 decades in part designing and building acoustical stuff - mostly microphones, but also loudspeakers. If you think you can do accurate acoustical testing at home, you are mistaken. The kind of gear you need to do that includes a purpose built anechoic room, a whole lot of B&K equipment, and a LOT of schooling to understand what you are doing.

I completely agree, especially the part about an anechoic environment and the schooling to know what you are doing (and when the numbers you measure aren't right).

 

[fdeck]

Among other things, I dabble in homemade speakers, and have done a fairly deep dive into how speakers work and how measurements work. Meanwhile I also have no hope of equipping myself with a commercial quality acoustic test facility, yet I want to test and understand things anyway.

I've developed a pretty good hunch that the theoretical small-signal low frequency model of a sealed or ported speaker, assuming good input data such as accurate specs, is likely to be more accurate and useful than a home measurement. For this reason I focus my measurements on trying to confirm that I got the input data right, tuned the port frequency as per my intentions, etc.

Then I go and play it.

By day I make my living from understanding how measurements work, and questioning whether they are accurate or not, although not in the audio domain. It's possible to verify a measurement system from scratch -- after all, NIST can do it. But it's certainly doing things the hard way unless your business is actually in doing measurements that have not been commercialized yet.

 

[darwin-bass]

And while the lowest octave is important, the overall sound of a bass speaker is more than just that lowest octave.

Measurements and numbers are interesting but don't always tell the full story.

 

[mike buzzetti]

If you want to know what a speaker is really doing, use a laser interferometer.

 

[agedhorse]

If you want to know what a speaker is really doing, use a laser interferometer.

This gives a different set of data not terribly related to the acoustic measurements being discussed, though it can be a useful tool for exploring how the materials behave mechanically.

 

[darwin-bass]

You can't get the sound from a story in a magazine.

 

[mike buzzetti]

This gives a different set of data not terribly related to the acoustic measurements being discussed, though it can be a useful tool for exploring how the materials behave mechanically.

Add a spectrum analyzer and you get excursion/extension and audio/freq. data , I would like to see that actually. At a very high resolution.

 

[byacey]

If you are going to accuse manufacturers of being dishonest, you should understand how gross inaccuracies in your measurements and their interpretation might contribute to your erroneous conclusions.

1. The red curve data reads as: F3=60Hz, F6=55Hz and F10=50Hz

2. The green curve data reads as: F3=55, F6=35Hz and F10=30Hz

In both cases your own data doesn’t support your conclusion.

Now for your data, the shapes of the curves indicate that these measurements include boundary interference which make the data inaccurate for comparison. Anechoic measurements that do not contain boundary artifacts, have a different LF shape than your curves.

Making accurate and consistent acoustic measurements is challenging under ideal conditions, and virtually impossible under typical room conditions. Making measurements and making accurate measurements are completely different things.

Accusing somebody (2 different manufacturers in this case) of being dishonest based on your defective measurements AND your inaccurate conclusions (fall like a rock below 80Hz) base on those same graphs, is unfair to both of those manufacturers.

I was going to respond, but you beat me to the draw.
The closest thng to an anechoic chamber for testing is a wide open hay field on a calm day, away from any buildings or any other reflective boundaries.
That's how I test my cabinets.

Testing in an enclosed room introduces all sorts of errors due to reflection, resonances and cancellation.