Stacking cabs

[bass_ferret]

[quote name='stevie' post='221376' date='Jun 18 2008, 01:47 PM']I suppose a 4 x 12" could be considered a side-by-side design. Limiting vertical dispersion to control unwanted reflections is common practice but a 4 x setup limits dispersion by lobing both vertically and horizontally. So, to be fair, it's not strictly side-by-side.[/quote]
The 4x12 and 8x10 cabs came about simply as a way to have enough drivers to handle the power back in the early days. But PA cabs from the same period were vertically aligned 4x12 cabs - thats why you sometimes hear old timers like me talking about PA columns. The reason for the 4x12 guitar cabs being two and two was so you could put your amp on top.

[Bill Fitzmaurice]

[quote name='lowhand_mike' post='221142' date='Jun 18 2008, 04:43 AM']

ha i just thought one was a backup. doh!

bill i'm glad you mentioned about being able to have side by side configurations if you go one wavelenthg out of p[hase or what ever it was. i was wondering about that last night. as in why cant we actually still have speakers side by side but performing correctly?[/quote]You can, as seen in this pic of a typical PA line array cab

The woofers are at either end of the cab, crossed over at 350 Hz to the mids that lie just inboard of them. Being closer together the mids can run to 1.5kHz, where they cross to the center mounted HF drivers.



[quote name='alexclaber' post='221378' date='Jun 18 2008, 08:55 AM']Something I've noticed from modelling drivers in WinISD Pro is that the phase difference between models is rarely so huge as to cause cancellation if the cab tuning frequency is the same.[/quote]
It's a bit more complicated than that, and while I'd rather not get even deeper into the science of it, time align also enters the equation. Phase response is the major culprit at low frequencies, and if the cabs are properly tuned to their drivers one would expect a 2x10 and a 1x15 fb to be off by at least 10 Hz. In the midbass phase response becomes moot, but when you hit the midrange time-align becomes critical. For the best known example research the (in) famous Eleanor Powell tap dancing fiasco that led to the development of the Altec A7 style of theater boxes. For the sake of simplicity I lump the phase response and time align issues into the same bundle, since time align is a phase issue as well, though from a different source.

[alexclaber]

Aha!

"This entire thing goes back to the Eleanor Powell "double tap" incident at MGM studios in the early 1930s. When monitoring playback of Powell tapdancing an echo was noticed on the taps. John Hilliard, subsequently the greatest of all horn designers, was a young sound engineer at MGM and traced the problem to the 8 foot difference in the path lengths of the horns in the 2-way Western Electric monitor speaker.

Hilliard did experiments that showed that the effect was time and frequency dependent and that a delay of less than 3 milleseconds (about 3 feet) was inaudible using crossvers between 350 to 800hz.

A result of this incident and WE's refusal to market their improved Fletcher loudspeaker was the decision of MGM sound honcho Douglas Shearer for MGM to design their own improved system which would among other things minmize time delay. Hilliard was put in charge of the project which then developed the famous Shearer Horn. An entire galaxy of talent worked on this system including Hilliard, James Lansing, Bob Stephens and even RCA's Harry Olson.

Note that though the folded basshorn of the Shearer cut time delay compared to the WE snail horns it didn't eliminate it totally but Hilliard's later Altec Voice of the Theatre did. So it seems that even though Hilliard thought some delay was inaudible the existence of any at all still nagged at him."

Alex

[lowhand_mike]

cheers alex, i couldn't find that

interesting to see how early good results were formed and that this far down the line things haven't changed in instrument cabs (well some people are pushing it)

[alexclaber]

[quote name='lowhand_mike' post='221453' date='Jun 18 2008, 03:37 PM']interesting to see how early good results were formed and that this far down the line things haven't changed in instrument cabs (well some people are pushing it)[/quote]

Look how many people spend all that money on an iPod and then proceed to listen to it through the original headphones - if only they knew how much better it could sound! To a large degree it's the same with cabs.

Alex

[stevie]

[quote name='alexclaber' post='221428' date='Jun 18 2008, 03:06 PM']Aha!

"This entire thing goes back to the Eleanor Powell "double tap" incident at MGM studios in the early 1930s. When monitoring playback of Powell tapdancing an echo was noticed on the taps. John Hilliard, subsequently the greatest of all horn designers, was a young sound engineer at MGM and traced the problem to the 8 foot difference in the path lengths of the horns in the 2-way Western Electric monitor speaker.

Hilliard did experiments that showed that the effect was time and frequency dependent and that a delay of less than 3 milleseconds (about 3 feet) was inaudible using crossvers between 350 to 800hz.

A result of this incident and WE's refusal to market their improved Fletcher loudspeaker was the decision of MGM sound honcho Douglas Shearer for MGM to design their own improved system which would among other things minmize time delay. Hilliard was put in charge of the project which then developed the famous Shearer Horn. An entire galaxy of talent worked on this system including Hilliard, James Lansing, Bob Stephens and even RCA's Harry Olson.

Note that though the folded basshorn of the Shearer cut time delay compared to the WE snail horns it didn't eliminate it totally but Hilliard's later Altec Voice of the Theatre did. So it seems that even though Hilliard thought some delay was inaudible the existence of any at all still nagged at him."

Alex[/quote]

So, would it be fair to say that Youngatheart is OK to stick a 1x15 on top of his 2x10 if Eleanor Powell's tapdancing sounds OK through the rig?

Or not?

[gypsymoth]

tap dancers don't buy amps with, or record with ..... reverb?
quite obviously things like room sound that some people find desireable as it adds dimension are extremely upsetting to certain others.
on another thread someone used the term "musicianal". maybe it applies here as well.

[The Funk]

You know, we should ask Youngatheart how his stack sounds with the 1x15 on top of the 2x10 and then to compare it to the cabs stacked the other way around.

When I had a 2x10 and a 1x15, I found the 1x15 dominated the 2x10 slightly even though it was less sensitive. Later I tried running the 2x10 full-range and just the lows to the 1x15. It sounded good at low volumes but at gigging volumes the 1x15 would distort. Once I learned about the limitations of traditional bass cabs I found a solution elsewhere.

[bass_ferret]

[quote name='alexclaber' post='221428' date='Jun 18 2008, 03:06 PM']A result of this incident and WE's refusal to market their improved Fletcher loudspeaker was the decision of MGM sound honcho Douglas Shearer for MGM to design their own improved system which would among other things minmize time delay. Hilliard was put in charge of the project which then developed the famous Shearer Horn. An entire galaxy of talent worked on this system including Hilliard, James Lansing, Bob Stephens and even RCA's Harry Olson.[/quote]
Would that be James B Lansing?

[lowhand_mike]

[quote name='stevie' post='221463' date='Jun 18 2008, 03:52 PM']So, would it be fair to say that Youngatheart is OK to stick a 1x15 on top of his 2x10 if Eleanor Powell's tapdancing sounds OK through the rig?

Or not?[/quote]


er... no

if you are listening to tap dancing through a bass rig it may be time to go to rehab.

[alexclaber]

[quote name='lowhand_mike' post='221484' date='Jun 18 2008, 04:07 PM']if you are listening to tap dancing through a bass rig it may be time to go to rehab. [/quote]

No, no, no.

Alex

[stevie]

[quote name='Bill Fitzmaurice' post='220890' date='Jun 17 2008, 07:43 PM']Stevie, you'd have a lot more success arguing the fine points of loudspeaker design if you understood any of them. If you did you'd know that drivers may be placed on the horizontal plane if they are crossed over below the frequency that is 1 wavelength at their CTC spacing.
Debating the laws of acoustics is a waste of my time, as being laws they are not subject to debate. I'm usually quite patient at explaining said laws and how they affect gear choices to those who have an interest in furthering their education. OTOH you strike me as one who clearly has already acquired all the knowledge he ever cares to, and that being the case please refrain from wasting any more of my time.[/quote]

1 wavelength is way too much for interdriver spacing. Anyone who familiar with the laws of acoustics would know that where the time displacement between two low frequency drivers corresponds to one-half of one wavelength, the outputs of the two low frequency drivers will null. 180 degrees and all that. Spacing needs to be less than half a wavelength. Back to the Loudspeaker Cookbook for you.

It's interesting that you use the term 'debate' here, because I have not seen you debating on any of the threads you have been involved in on this forum - merely pronouncing, and belittling others.

[Raggy]

What about these cabs with 2x12" drivers, placed diagonally??

Is there any benefit to those??

[Bill Fitzmaurice]

[quote name='stevie' post='221527' date='Jun 18 2008, 11:47 AM']1 wavelength is way too much for interdriver spacing. Anyone who familiar with the laws of acoustics would know that where the time displacement between two low frequency drivers corresponds to one-half of one wavelength, the outputs of the two low frequency drivers will null. 180 degrees and all that. Spacing needs to be less than half a wavelength. Back to the Loudspeaker Cookbook for you.

It's interesting that you use the term 'debate' here, because I have not seen you debating on any of the threads you have been involved in on this forum - merely pronouncing, and belittling others.[/quote]Stevie, the one compliment I will pay to you is that you remind me very much of the Honorable President of the United States, George W. Bush. Like he, everytime you open your mouth you somehow manage to stick your foot further down your throat than the time before.
Your above statement is complete and utter gibberish. I'll let Alex point out why if he cares to, I have far more important things to attend to. Cutting my toenails is first on the list.

Edited June 18, 2008 by Bill Fitzmaurice

[lowhand_mike]

[quote name='Raggy' post='221532' date='Jun 18 2008, 04:53 PM']What about these cabs with 2x12" drivers, placed diagonally??

Is there any benefit to those??[/quote]


again something else rattling around in my brain, which i promptly forgot.
do they get away with the out of phase thing or are they half out of phase so not quite so bad?

i sure wouldn't want to try and stack them so the drivers are verticle, though the final thing might look quite cool.

[Raggy]

I am wondering also if that is why the Berg NV610 has its speakers in 2 rows at slightly different levels.

[stevie]

[quote name='Bill Fitzmaurice' post='221538' date='Jun 18 2008, 04:58 PM']Stevie, the one compliment I will pay to you is that you remind me very much of the Honorable President of the United States, George W. Bush. Like he, everytime you open your mouth you somehow manage to stick your foot further down your throat than the time before.
Your above statement is complete and utter gibberish. I'll let Alex point out why if he cares to, I have far more important things to attend to. Cutting my toenails is first on the list.[/quote]

That really is not a very convincing reply, but I must accept that it's the best you can do.

[Raggy]

i sure wouldn't want to try and stack them so the drivers are verticle, though the final thing might look quite cool.

+1
[/quote]

[stevie]

I notice you are still perusing the board, Bill. I thought you had better things to do.

[lowhand_mike]

[quote name='Raggy' post='221550' date='Jun 18 2008, 05:14 PM']I am wondering also if that is why the Berg NV610 has its speakers in 2 rows at slightly different levels.[/quote]

like this one



or this one

[Raggy]

[quote name='lowhand_mike' post='221555' date='Jun 18 2008, 05:17 PM']like this one



or this one


[/quote]


Thats the ones.

Cracking looking cabs them!!!!!!

[lowhand_mike]

[quote name='stevie' post='221554' date='Jun 18 2008, 05:16 PM']I notice you are still perusing the board, Bill. I thought you had better things to do.[/quote]


give it a rest guys.

stevie if you can provide a link to prove your point then please do so as it would be informative reading (i'm a geeking it up tonight )

i'm sure if you could actually prove this information then it would be of great benifit to bill

where as bill info has always been well backed up.

otherwise can it. :ph34r:

[bass_ferret]

A little knowledge can be a dangerous thing

There are quite a few cabs with diagonally aligned drivers - lots of EBS, Epifani, Aguillar cabs. Lots of 2x12 and 4x12 cabs are often the size of 4x10's and 8x10's with the drivers diagonally arranged - like my old EBS.



I guess this is probably just to keep the cabs the same width but it might help reduce comb filtering.

[BB2000]

[quote name='stevie' post='221527' date='Jun 18 2008, 04:47 PM']1 wavelength is way too much for interdriver spacing. Anyone who familiar with the laws of acoustics would know that where the time displacement between two low frequency drivers corresponds to one-half of one wavelength, the outputs of the two low frequency drivers will null. 180 degrees and all that. Spacing needs to be less than half a wavelength. Back to the Loudspeaker Cookbook for you.

It's interesting that you use the term 'debate' here, because I have not seen you debating on any of the threads you have been involved in on this forum - merely pronouncing, and belittling others.[/quote]

I wish you wouldn't bait Mr. Fitzmaurice, because his posts are always worth a read. In your case a little (or should that be no?) knowledge is a dangerous thing.

[Merton]

[quote name='BB2000' post='221567' date='Jun 18 2008, 05:34 PM']I wish you wouldn't bait Mr. Fitzmaurice, because his posts are always worth a read. In your case a little (or should that be no?) knowledge is a dangerous thing.[/quote]
plus the 1