cabinet frequency response

[acmebass]

I think all of those things are being discussed, ad infinitum, many of them over and over again, except "off-axis power response," which doesn't exist. Power knows no axis, it's just power.


"Response" is the distinction here.
Maybe just the term "power response" would have been better?
Or "off axis response"?

Yeah- sorry- didn't mean to be so picky.

Andy

 

[acmebass]

um--I'm using 5's, 6.5's and 8's to good ends. Low f3's and pretty good efficiency---the 5's are stock but the 6.5's and 8's are also by Eminence's wizard designer.

Ok---I assume that all of us guys making speakers check out each other's stuff. I gotta tell you---I was looking at Andy's and Roger's sites---man---they are really good values.

Thanks, Mike. Please show a link to Roger's! I don't know who you're talking about.

As far as smaller drivers go, I've observed that to "handle" low frequencies, without necessarily "reproducing" them is sufficient to give a great many people a wholly satisfying sound. Probably not necessary to belabor the distinction until we're all blue in the face!

Thanks,
Andy

 

[bryanspkr]

Ever notice how many 2nd hand home hi-fi subs are for sale?

 

[bryanspkr]

Yeah- sorry- didn't mean to be so picky.

Andy

BTW Andy, I have your first low B-1
Its been in many places over the years. My " Country and Blues" cab.

 

[acmebass]

Bruce Kent here. (LOL)

BTW, I wish that I had thought of this overdrive/BL thing on my own, but I didn't. It was figured out years ago. I came across this in different articles/papers over the years. It is briefly discussed in JBL Technical Note Volume 1, Number 9, Distortion and Power Compression in Low Frequency Transducers". They actually state that this (loss of BL during overdrive) was intentionally "designed into the transducer (E140-8) to add warmth and 'punch' to bass guitar sound reproduction". Without knowing this, a person would have to be highly skeptical of the claims often made about great bass from these drivers because they are way over damped (Qts ~0.17). Most folks just assume that this is the result of designing for maximum efficiency.

Bob Pody

Thanks, Bob. Two things:

Yeah, I would be included in the group of people who made that assumption!

The other thing is that, as is sort of implicit, there is really very little that is "new." Moving coil drivers have been in use for over a century, and pretty much everything has been thought of.

As the years go by, I am amused every time somebody comes up with a bold new innovation which was also a bold new innovation 20 or more years ago. It happens all the time.

So, to me, it's mainly about trying to have the best understanding of the existing body of knowledge, and doing a good job of execution. Ultimately, in the area of moving coil loudspeakers, there is precious little which could be considered particularly new. It's all been done before, and by smarter people than we are!

Thanks,
Andy

 

[acmebass]

Ever notice how many 2nd hand home hi-fi subs are for sale?

Yeah, I have.

I picked up a Sunfire last year to use with my 6" Tannoy dual concentrics for a pretty good price. Covered it with oak, and it's pretty cool.

But yeah, people are giving away their subwoofers.

Andy

 

[acmebass]

BTW Andy, I have your first low B-1
Its been in many places over the years. My " Country and Blues" cab.

Thanks, Bryan. Glad you like it!

A

 

[bryanspkr]

Thanks, Bob. Two things:

Yeah, I would be included in the group of people who made that assumption!

The other thing is that, as is sort of implicit, there is really very little that is "new." Moving coil drivers have been in use for over a century, and pretty much everything has been thought of.

As the years go by, I am amused every time somebody comes up with a bold new innovation which was also a bold new innovation 20 or more years ago. It happens all the time.

So, to me, it's mainly about trying to have the best understanding of the existing body of knowledge, and doing a good job of execution. Ultimately, in the area of moving coil loudspeakers, there is precious little which could be considered particularly new. It's all been done before, and by smarter people than we are!

Thanks,
Andy

Materials, quality to cost ratio (I.E. Eminence etc.), and of course amp power catching up to some older speaker technology have made big differences.

 

[bryanspkr]

Thanks, Bryan. Glad you like it!

A

serial number 1. Not just the first model.

 

[bongomania]

I've observed that to "handle" low frequencies, without necessarily "reproducing" them is sufficient to give a great many people a wholly satisfying sound.

This is an important distinction actually--it seems just as difficult to find a cab that doesn't fart out too easily on low frequencies, as it does to find a cab that can reproduce those frequencies.

If I could only buy one of two qualities, "plays 27 Hz at 3 dB down" or "doesn't fart out when hit with big low peaks", I would pick the second one in a heartbeat.

 

[bryanspkr]

Yeah, I have.

I picked up a Sunfire last year to use with my 6" Tannoy dual concentrics for a pretty good price. Covered it with oak, and it's pretty cool.

But yeah, people are giving away their subwoofers.

Andy

In the end, the only system I kept was a pair of lowther Bicors (talk about older design!) and a Volt sub. Its very rare that I use the sub. As a bass player (as most speaker nuts seem to be), I find that as I get older, I shy away more from the low end in my listening habits.
I have the traditional high freq. rolloff that comes with aging males too.

 

[Vince Klortho]

Man--you want to hear a funny story? I was involved in the design of a little digital amp for a known amp manufacturer that was geared for guys that double. Now with upright--an HPF is really a necessity. Piezos put out an insane amount of subsonic information. So I said they needed to put in an adjustable HPF. They did. Let's just say that I didn't imagine that they needed to be told that 6db/octave was just this side of useless.They wouldn't change it to 24. Oh well.

The components for a few more filter stages would have been a few dollars at most. I guess they had a budget to watch.

 

[acmebass]

Materials, quality to cost ratio (I.E. Eminence etc.), and of course amp power catching up to some older speaker technology have made big differences.

Absolutely.

 

[acmebass]

serial number 1. Not just the first model.

That's right. Through Judith in New York. You got the first 4 ohm unit, and Senor Jung got the first 8 ohm. October, 1999.

Wow.

Good to hear from ya.

Thanks,
Andy

 

[bryanspkr]

That's right. Through Judith in New York. You got the first 4 ohm unit, and Senor Jung got the first 8 ohm. October, 1999.

Wow.

Good to hear from ya.

Thanks,
Andy

I've been meaning to write you for a while. I've been following you all these years though, Checking on your developments and rooting for your success.
I did show that cab everywhere in europe and left it in a friends bass atelier in the netherlands for a long stretch (Hopefully you made a few extra sales). Thanks again for the tips and the time. Though a bit late I know.

 

[bryanspkr]

That's right. Through Judith in New York. You got the first 4 ohm unit, and Senor Jung got the first 8 ohm. October, 1999.

Wow.

Good to hear from ya.

Thanks,
Andy

BTW, If you are ever in Amsterdam you are always welcome.

 

[Arjank]

BTW, I wish that I had thought of this overdrive/BL thing on my own, but I didn't. It was figured out years ago. I came across this in different articles/papers over the years. It is briefly discussed in JBL Technical Note Volume 1, Number 9, Distortion and Power Compression in Low Frequency Transducers". They actually state that this (loss of BL during overdrive) was intentionally "designed into the transducer (E140-8) to add warmth and 'punch' to bass guitar sound reproduction". Without knowing this, a person would have to be highly skeptical of the claims often made about great bass from these drivers because they are way over damped (Qts ~0.17). Most folks just assume that this is the result of designing for maximum efficiency.

With respect to choosing between a normally damped/large Xmax design or an over damped/overdrive design, I think that both approaches are legitimate. I suspect that most designers inherently prefer a more linear design (normally damped, large Xmax).

That BL "thing" indeed aint new. I read about it in a German magazine years ago. But then again it's not only the BL that matters here, though the Qes does alter when more and more windings leave the airgap, the suspension characteristics and powercompression(read heating of voice-coil = impedance increase = higher Qes) have to be taken into this matter too.
Btw. great to have you onboard Astrosonic

 

[Mike Arnopol]

This is an important distinction actually--it seems just as difficult to find a cab that doesn't fart out too easily on low frequencies, as it does to find a cab that can reproduce those frequencies.

If I could only buy one of two qualities, "plays 27 Hz at 3 dB down" or "doesn't fart out when hit with big low peaks", I would pick the second one in a heartbeat.

I'd love to see Arjank and others chime in on this. In my experience the Eminence Kappalites while going insanely loud before smacking the voice coil, tend to get "farty" sooner than a lot of the Faitals. Greenboy commented on how the Faitals tend to "clip"--or whatever more gracefully. When building little cabs with the Faital 8 it didn't give much warning before it smacked. A good and a bad thing. It didn't display the 'fartiness" that I'm used to with other drivers--it went very loud for it's size (claiming an 8.1 xmax---but Faital and others use a different way to measure xmax---more like 6mm as compared to an Eminence) but when it was done--it was done. I prefer this, but one does need to be more careful.

In comparing an enclosure with 8 5" Faitals against a 3015lf loaded cab---the lf went just a tad further before smackdown but the cab with the 5's went a lot louder than the lf before sounding really farty. The 5's smacked just a tad earlier but sounded good until.

Arjank---you were saying in another thread on the difference designers choose as far as the magnetic field extending further or something like that.Is that what's going on here? (comparing Faital's to Eminence's design choices)

 

[AstroSonic]

That BL "thing" indeed aint new. I read about it in a German magazine years ago. But then again it's not only the BL that matters here, though the Qes does alter when more and more windings leave the airgap, the suspension characteristics and powercompression(read heating of voice-coil = impedance increase = higher Qes) have to be taken into this matter too.
Btw. great to have you onboard Astrosonic

+1

The JBL Tech Note actually describes this (BL loss, surround compliance changes and thermal compression). The increased voice coil resistance caused by increased voice coil temperature both causes compression and increased Qes and Qts. The compliance of the surround decreases at larger excursions, causing a rise in Fs. The net result is basically as discussed earlier - a shift in alignment which produces more energy between 60 and 150Hz, and potentially strong peaking centered in the range of 80-120Hz (but covering the 60-150Hz range). The sonic impact of the latter is washed out detail ('mud') and a large decrease in perceived definition and articulation. This is easy to simulate if your EQ allows boosting in this range. A safe bet would be that the greater simplicity of these interactions in a sealed design would make it less impacted (the design is more stable from low to high power use). In any case, if a cab is designed with these interactions taken into account, it should be able to produce deep bass without muddying the sound. It will at least deliver clean deep bass into the room, which the room acoustics will then alter. If you don't deliver a clean bass signal into the room you certainly won't be able to hear clean deep bass.

To really evaluate the performance of high power bass cabs these effects need to be taken into account. Most of the reasonably priced (and commonly used) modeling programs are only small signal models.

Briefly going off-topic, the increase in voice coil resistance can really bugger up crossover design, as the impedance curve is essentially shelved upward. Zobels do not solve this.

Thanks for the welcome. Lots of great people here in the TB community.

 

[B-string]

+1

[snip]

Briefly going off-topic, the increase in voice coil resistance can really bugger up crossover design, as the impedance curve is essentially shelved upward. Zobels do not solve this.

Thanks for the welcome. Lots of great people here in the TB community.

We used to have a user here that stated often that LF drivers not included in crossovers was taking the "cheap way out" in bass guitar cabs. You have stated the reason I find low pass in high power cabs a minus not a plus. Great for power limited HiFi, not in high power cabs. Electronic crossovers for Bi-amp and Tri-amp high power systems were developed with this problem in mind.