Speaker size

[mikejdexter]

Do you think the small speakers used in some of the manufacturers cabinets made today carry the same 'depth' of sound at the bottom end as a single 12" speaker?

Is cabinet design so important to the sound?--as say, just putting a 12" speaker in a solid wooden box?

[drurb]

Originally Posted by mikejdexter

Do you think the small speakers used in some of the manufacturers cabinets made today carry the same 'depth' of sound at the bottom end as a single 12" speaker?

Is cabinet design so important to the sound?--as say, just putting a 12" speaker in a solid wooden box?

Cabinet design is crucial! The driver(s) and cabinet are a system.

[mikejdexter]

Many thanks for your reply and the link---good info.

[drurb]

Originally Posted by mikejdexter

Many thanks for your reply and the link---good info.

My pleasure-- take a look here too.

[Turnaround]

Originally Posted by drurb

Cabinet design is crucial! The driver(s) and cabinet are a system.

It's interesting to me that you bring forth the Thiele Small design concepts - they date back to the early 1960's. Though they form the foundation of modern speaker system design the advancements made since have been significant.

In 2001, for instance, Joshua Leeds published information about psycho-acoustics that have been adopted by many audio systems manufacturers for the last decade. The results of the adoption of this branch of acoustic design has had impacts in almost every branch of audio reproduction.
A common adaptation of this information is in the design of sub-miniature earphones used on devices such as iPods. The tiny drivers in these earpieces are capable of delivering a percieved bass response beyond what is capable from the understandings of a Thiele Small system - at least in a conventional sense.

Still, I must agree that cabinet design is crucial. So is speaker design, for in the spirit of what was being said here it is the entire system that makes it all work - speakers, cabinet, crossover, color of the speaker cone.

OK, I lied about the last one..

[drurb]

Originally Posted by Turnaround

It's interesting to me that you bring forth the Thiele Small design concepts - they date back to the early 1960's. Though they form the foundation of modern speaker system design the advancements made since have been significant.

In 2001, for instance, Joshua Leeds published information about psycho-acoustics that have been adopted by many audio systems manufacturers for the last decade. The results of the adoption of this branch of acoustic design has had impacts in almost every branch of audio reproduction.
A common adaptation of this information is in the design of sub-miniature earphones used on devices such as iPods. The tiny drivers in these earpieces are capable of delivering a percieved bass response beyond what is capable from the understandings of a Thiele Small system - at least in a conventional sense.

Still, I must agree that cabinet design is crucial. So is speaker design, for in the spirit of what was being said here it is the entire system that makes it all work - speakers, cabinet, crossover, color of the speaker cone.

OK, I lied about the last one..

With regard to psychoacoustics, I suggest you read this.

Pschoacoustics (not psycho-acoustics) is not a branch of design. The perceived bass response of in-ear phones is no mystery. It is understood quite clearly from the point of view of the pressure wave and the middle-ear mechanics.

This is what appears on Joshua Leed's website:

Joshua Leeds is a sound researcher, music producer and educator. He is one of few published authorities in the field of psychoacoustics–the study of the effects of music and sound on the human nervous system.

One of the few published authorities in the field of psychoacoustics? That's absolute nonsense! It's also an insult to the many talented scientists who have actually published in the field. Psychoacoustics is not "the study of the effects of music and sound on the human nervous system" despite what Joshua Leeds says. In fact, I could find NOTHING published by Joshua Leeds in premiere international scientific journals that publish actual psychoacoustic research. He has, however, published his own ideas in a series of books in the lay press.

Snake oil.

If you really want to learn about psychoacoustics, I suggest this as a good place to start. It's a text by an actual psychoacoustician and a very talented one at that.

Finally, if you would like to delve into the field, I suggest you consult the journal that has been the premiere place to publish such research for the past 80 years. That would be right here.

Back on topic, what the OP asked was about the importance of cabinet design. The Thiele-Small parameters and example software I cited allow one to predict/determine the frequency response of a driver/cabinet combination. That's physics. To the extent that psychophysics (here, psychoacoustics) comes into play, it would be to help to determine what is the desired response. Once known, the Thiele-Small parameters and "alignment" procedures could be used to help achieve that desired response.

[Govier966]

Originally Posted by Turnaround

It's interesting to me that you bring forth the Thiele Small design concepts - they date back to the early 1960's. Though they form the foundation of modern speaker system design the advancements made since have been significant.

In 2001, for instance, Joshua Leeds published information about psycho-acoustics that have been adopted by many audio systems manufacturers for the last decade. The results of the adoption of this branch of acoustic design has had impacts in almost every branch of audio reproduction.
A common adaptation of this information is in the design of sub-miniature earphones used on devices such as iPods. The tiny drivers in these earpieces are capable of delivering a percieved bass response beyond what is capable from the understandings of a Thiele Small system - at least in a conventional sense.

Still, I must agree that cabinet design is crucial. So is speaker design, for in the spirit of what was being said here it is the entire system that makes it all work - speakers, cabinet, crossover, color of the speaker cone.

OK, I lied about the last one..

Im not sure you lied about the last one, i though that was what made markbass cabs so nice.

[fdeck]

Originally Posted by drurb

To the extent that psychophysics (here, psychoacoustics) comes into play, it would be to help to determine what is the desired response. Once known, the Thiele-Small parameters and "alignment" procedures could be used to help achieve that desired response.

+100. In my own explorations into speaker design, I have learned that a vital factor is knowing what you want in the first place, from a musical perspective, then being able to translate that knowledge into a set of technical requirements that can drive the design process. Thiele-Small theory was never intended to tell us what sounds good. However, if you have a signal source that already sounds good, T-S theory can help you figure out how to reproduce the low frequency content of that source.

As for the OP, it is possible to start with any speaker, and design one with a smaller cone that has the same low-frequency response curve. However, tradeoffs are necessary, and the most likely victim is the volume level that can be produced. However, a small driver might still be plenty loud for your intended use.

[mikejdexter]

Thanks for your replies--pretty tecnical stuff. Very good info. 'And here I am still playing-'Margie'!

[jon3673]

OK, here’s my 2 cents worth.
Like drurb said, “Cabinet design is crucial”!
Having a properly ported speaker cabinet can make a huge difference in the lo end response abilities of a speaker. This physical shortcut was developed in order to off set the limitations of the speaker. However, things have really changed over the years and we now have some very efficient and wonderful speakers out there on the market. Therefore, using a ported cabinet is no longer really essential.
I found, when I was first going through this amplification experiment, that the very best frequency response and UB reproduction sound that I ever got was by using a couple of stacked Bose 802 speaker cabinets driven by a Walter Woods. I have never heard any reproduction better! This essentially provided me with the more speaker surface than using two 18” speakers, but it also gave me good high frequency response, as well as, all of the low end needed. In small rooms I would use just one Bose 802 and that normally covered my needs very well. Again, a single Bose 802 has more speaker surface than an 18” speaker cabinet. (and much less size, plus it has good high end responce!)
I walked away from using them because they are a real pain to set up and tear down! I simply reverted back to my old Ampeg B15, because, after putting larger rollers on it, I could lay my UB on top of it and easily roll the whole thing in and out as one load! As I use a lo B on my upright, I converted the B15 over to an 18” speaker, and this helped considerably.
I must admit though, I did get another UB fellow hooked on the Bose sound and he still uses the WW/Bose arrangement. (But he’s much younger than I am!) . . . . . . . (and, disgustingly, . . . . . . a much better player!)
Anyway, I wound up working a gig that had limited stage space and my Ampeg was taking up too much room. I compromised by building a downward facing speaker into my music stand (as this was a reading gig!). It’s common knowledge that lower frequencies tend to travel along the floor, so a downward facing speaker becomes much more efficient for use with an UB. I have found that I get just as good a response and volume with a down facing 10” speaker as I do with a forward facing 18” speaker.
Well, this gig went on for a while and sounded good, but I wanted it to sound better. There was a second raised level behind me that would allow me to set up an extension speaker. I felt that I needed more high end response, so I was able to obtain an Acoustic Image Ex cabinet to use in that location. It made night and day difference in the sound! And, because of this experience, I have now converted exclusively to the AI Contra as my main rig and use the AI EX speaker on those occasions that require more coverage. Again, this is using 10” down facing speakers.
Therefore, to answer your question, given a good frequency response speaker, the design of the cabinet can make all of the difference in the world. However, if you want to get the full range coverage for your ax, you’ll probably need both high and lo end speakers. (maybe even a mid-range!).
So, you’ve got a fun path in front of you. You'll enjoy experimenting!

[drurb]

Originally Posted by jon3673

OK, here’s my 2 cents worth.
Like drurb said, “Cabinet design is crucial”!
Having a properly ported speaker cabinet can make a huge difference in the lo end response abilities of a speaker. This physical shortcut was developed in order to off set the limitations of the speaker.

If one studies the history of enclosure designs, which I have, one will find that the above is not really accurate. Much of this history stems from the development and use of hi-fi music reproduction systems. Ported designs are as useful today as they always were. Porting is a means to extend the low-frequency response of the system without suffering a great loss in efficiency. Yes, it has it's drawbacks but it's a matter of tradeoffs among the classic three: cabinet size, efficiency, and low-end response.

Originally Posted by jon3673

However, things have really changed over the years and we now have some very efficient and wonderful speakers out there on the market. Therefore, using a ported cabinet is no longer really essential.

It never was essential. It was smart. Infinite baffle designs were also in use during the heyday of the developments in ported designs.

Originally Posted by jon3673

I found, when I was first going through this amplification experiment, that the very best frequency response and UB reproduction sound that I ever got was by using a couple of stacked Bose 802 speaker cabinets driven by a Walter Woods. I have never heard any reproduction better! This essentially provided me with the more speaker surface than using two 18” speakers, but it also gave me good high frequency response, as well as, all of the low end needed. In small rooms I would use just one Bose 802 and that normally covered my needs very well. Again, a single Bose 802 has more speaker surface than an 18” speaker cabinet. (and much less size, plus it has good high end responce!)

It's not really about driver surface area. Rather it is about acoustic power output. Now, the Bose 802 is not a very efficient speaker at all. It's frequency response is also very poor at the low end. One compensates by supplying it with plenty of power and providing a substantial boost in the low end. This sucks up amplifier power like nobody's business! It is here that we see what was one of the primary motivations for use of the the ported, bass-reflex cabinet designs so popular in the 1950's. It was simply that amplifier power was so hard to come by. With the advent of more and more powerful solid-state designs, amplifier power became cheap and clean. It was then that one witnessed the development and refinement of essentially non-ported speaker driver/cabinet designs where efficiency was no longer paramount. In fact, freed from the power restrictions and via tone-shaping, one could produce systems with a flatter low-end response (although there are drawbacks to this approach that I'll skip for now). I don't doubt for a moment that you could achieve a very good result using the Bose 802.

As far as instrument amplification goes, there is still great desirability in efficient cabinet designs (e.g., ported, transmission-line, etc.). This is because, given the sound-pressure levels we are often called on to produce, amplifier power can still be quite an issue.

Originally Posted by jon3673

It’s common knowledge that lower frequencies tend to travel along the floor.

It is not common knowledge at all among those trained in physical acoustics. Low frequencies are often transmitted through the floor purely as a result of the fact that the cabinets are usually in direct contact with the floor.

[anonymous02282011]

nice posts there doc!

[steve_n_his_urb]

I have a pair of these too, and the bass sounds just great through them. More bottom end than my 10" JBL. But in deference to Drurb's comments, it has to be noted that the Bose controller adds about 13dB boost at 60Hz to get a flattish overall response (plus a big boost at the high end). And Bose recommend a minimum power from your amp of 250W per speaker IIRC.

Having to put that 802C controller in the signal path is a pain, making sure you have all the necessary cables and enough ac outlets. So I prefer to use something else for a gig setup.

Steve

[drurb]

Originally Posted by steve_n_his_urb

I have a pair of these too, and the bass sounds just great through them. More bottom end than my 10" JBL. But in deference to Drurb's comments, it has to be noted that the Bose controller adds about 13dB boost at 60Hz to get a flattish overall response (plus a big boost at the high end). And Bose recommend a minimum power from your amp of 250W per speaker IIRC.

Having to put that 802C controller in the signal path is a pain, making sure you have all the necessary cables and enough ac outlets. So I prefer to use something else for a gig setup.

Steve

Bingo! Thanks for adding the detail.