ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 [2] 3   Go Down

Author Topic: 15in vs 12in  (Read 11801 times)

g'bye, Dick Rees

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7424
  • Duluth
Re: 15in vs 12in
« Reply #10 on: April 14, 2014, 09:33:01 pm »

Bazinga.
Logged
Pay no attention to the man behind the curtain...

Peter Morris

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1323
Re: 15in vs 12in
« Reply #11 on: April 15, 2014, 06:03:02 am »

Hi Philip,

As a rough guide - 15 inch speakers work in their piston range up to about 500 Hz, 12 inch speakers about 800 Hz, after which you are operating in the cone breakup frequency range.  Similarly a 1.75 diaphragm compression driver will only go down to about 1K2 Hz safely for PA applications.
 
Therefore the 12 and 1 combination has less of the spectrum where the speaker is operating outside of its optimum frequency range. Accordingly the 12 and 1 combination will be more articulate but will lack the bass capability of the 15 which can displace more air (assuming the same Xmax etc. for both).

If you want the 15 and horn to sound better you will need to use a bigger compression driver and cross at lower frequency, or use a mid-range driver to fill the gap between 500 & 1K2 Hz, but that's a whole new set of problems to solve.
 
Here’s RCF latest 15 + horn. It crosses at 650Hz http://www.rcf.it/en_US/products/touring-and-theatre/tt5-a. To achieve the low crossover frequency they have used a 4 inch diaphragm HF driver and large horn. The only problem is the break up modes in the VHF region of the compression driver.  I suspect it won’t sound as sweet in the VHF region but the compromise as a whole will be excellent.

So to answer your question - the 12 will sound better, the 15 will make more bass. If bass output is the limiting factor the 15 will be louder.
« Last Edit: April 15, 2014, 10:17:42 am by Peter Morris »
Logged

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6807
  • Boston, MA USA
Re: 15in vs 12in
« Reply #12 on: April 15, 2014, 09:25:25 am »

So to answer your question - the 12 will sound better, the 15 will make more bass. If bass output is the limiting factor the 15 will be louder.

Now that's a pretty broad stroke of the brush. That answer will depend on the quality of the cabinet/drivers, manufactures design, and installation type.
 
At the MI level, all bets are off, but at a professional level and with good cabinets a 15" driver in a two way cabinet can and usually will produce more otuput and usable sound at all frequencies, and the benefit being a smoother transition to the lower cabinets/subs.
 
My concern has always been this transition and the upper cabinets ability to cover the full audio spectrum down to the crossover center point. Few 12" speakers do this well in the common one over one point source configuration, where most quality 15" drivers are able to replicate all of the same frequencies the 12" driver will replicate with the added benefit of being able to replicate low/mid frequencies with more accuracy and detail.
 
There was a reason for my replacing ALL of my SRX722's with SRX725's, and it wasn't because the weighed less. ;D
Logged
BOSTON STRONG........
Proud Vietnam Veteran

I did a gig for Otis Elevator once. Like every job, it had it's ups and downs.

Peter Morris

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1323
Re: 15in vs 12in
« Reply #13 on: April 15, 2014, 10:14:59 am »


Now that's a pretty broad stroke of the brush. That answer will depend on the quality of the cabinet/drivers, manufactures design, and installation type.
 

Sorry  Bob - I thought in terms of responding to the original question it would have been assumed that we were talking about equivalent speakers in terms of design, build quality … even the same brand and series, just the 12 vs 15  but with both using the same HF components.
Logged

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6807
  • Boston, MA USA
Re: 15in vs 12in
« Reply #14 on: April 15, 2014, 12:29:51 pm »

Please don't appologize. Your statement could be assumed correct, but for the sake of clarity it's always best to be specific regardless of assumtion. Just my opinion based on the levels of knowledge of those who may be reading these replies and number of variables involved.

The OP ran a test based on his needs, came to a conclusion and asked for further guidence. His test, although basic and somewhat flawed, led to his conclusions based on his experience with a limited number of drivers and configurations. The answer for his question based on his test will be all the above and maybe.
Logged
BOSTON STRONG........
Proud Vietnam Veteran

I did a gig for Otis Elevator once. Like every job, it had it's ups and downs.

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16639
  • Hickory, Mississippi, USA
    • Resotune
Re: 15in vs 12in
« Reply #15 on: April 15, 2014, 12:43:25 pm »

I kind of liked Peter's answer... While you "could" make a 2 way 15" sound Ok, (I've heard some), all things equal it will be more challenged in the midrange than the 12".

Honestly both are challenged in the midrange for hifi fidelity, the higher SPL benchmark used for live sound may trade some midrange performance for the extra bass.

It is instructive to look at what combinations the manufacturers sell the most of. The marketplace over time, ultimately makes the final call on "cost effective, but doesn't suck too much" speakers. 

The ones that suck too much, eventually go away, and this speaker category is mature.

JR
Logged
When in doubt do what's right.

Jim McKeveny

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1115
Re: 15in vs 12in
« Reply #16 on: April 15, 2014, 06:09:38 pm »

When asked about wedge preferences, a young Cyndi Lauper said "15's are for boys. 12's are for girls"...
Logged

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6807
  • Boston, MA USA
Re: 15in vs 12in
« Reply #17 on: April 15, 2014, 06:31:49 pm »

Ever notice that the first thing out of peoples mouths when a new manufacturers line is announced is usually either, "I hope they offer a 15" wedge.", or, "Why don't they have a 15" wedge." I'm biased, I like good 15" drivers.
Logged
BOSTON STRONG........
Proud Vietnam Veteran

I did a gig for Otis Elevator once. Like every job, it had it's ups and downs.

Curtis H List (Too Tall)

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 91
Re: 15in vs 12in
« Reply #18 on: April 17, 2014, 10:25:00 am »

Hi Philip,

As a rough guide - 15 inch speakers work in their piston range up to about 500 Hz, 12 inch speakers about 800 Hz, after which you are operating in the cone breakup frequency range.  Similarly a 1.75 diaphragm compression driver will only go down to about 1K2 Hz safely for PA applications.
 
Therefore the 12 and 1 combination has less of the spectrum where the speaker is operating outside of its optimum frequency range. Accordingly the 12 and 1 combination will be more articulate but will lack the bass capability of the 15 which can displace more air (assuming the same Xmax etc. for both).


My friend Al Limberg used to bring in all his used boxes and current inventory when they they quit working.
He had a set of Yamaha Waveforce that used Eminence 15" and Eminence 1" throat compression driver mounted on a large conical hor. Diameter 15" or greater

My friend Al Limberg used to bring me all his used boxes and current inventory when they quit working.
He had a set of Yamaha Waveforce that used Eminence 15" and Eminence 1" throat compression driver mounted on a large conical horn. Diameter 15" or greater.
Except for a design flaw in the xover that blew up a couple of parts it was an impressive sounding box.
After I did measurements and some modeling I found a work-around that could stand the juice he put into the xover parts.

When finished Al rented these out more then any system he owned. Over time they made more money than any other system he used.

NOTE: For these to work you MUST use a large high frequency horn (Conical Preferred)
Also the xover is critical. It needs to be steep and sum well in the xover region.
At best you will still have some narrow band problems at or very close to the xover point.

Lastly there are some problems with directivity as mentioned above.
Not much you can do about this. I opted to go for “Flat” on axis and live with the off axis roll-off.

One last thing. I have measured more than a couple horns and my hand down winner is Conical.
Not very practical since they will not array together, but used one at a time I like them best.






If you want the 15 and horn to sound better you will need to use a bigger compression driver and cross at lower frequency, or use a mid-range driver to fill the gap between 500 & 1K2 Hz, but that's a whole new set of problems to solve.
 
Here’s RCF latest 15 + horn. It crosses at 650Hz http://www.rcf.it/en_US/products/touring-and-theatre/tt5-a. To achieve the low crossover frequency they have used a 4 inch diaphragm HF driver and large horn. The only problem is the break up modes in the VHF region of the compression driver.  I suspect it won’t sound as sweet in the VHF region but the compromise as a whole will be excellent.

So to answer your question - the 12 will sound better, the 15 will make more bass. If bass output is the limiting factor the 15 will be louder.
Logged

Richard Turner

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 551
Re: 15in vs 12in
« Reply #19 on: April 17, 2014, 11:44:04 am »

I've been using a pair of e210 yorkville as utility speakers for about 2 years now and could not be happier. they are 2 10" drivers and  1" exit horn idn D'Apallito (sp?) configuration.

the 2 of them fit in the same space as a single 115 box for packing just about 2" taller have almost the same lower cutoff frequency yet have a but more to offer in the low mids department

I've read other good comments about the JTR triple 8 which uses 3 8" driver with one having cocentric HF driver.

Myself I just dont think I would ever buy another 2 way 15 and horn box (still have a bunch that get used regularily) but I find better overall coverage with 2 12" boxes side by side. I'm guessing the test session you were doing was for a 1 box solution for small area coverage.
Logged
Looking at retiring. Local PA market has shrank to 2 guys with guitars and bose l1 compacts or expecting full line array and 16 movers on stage for $300... no middle left going back to event DJ stuff, half the work for twice the pay.

ProSoundWeb Community

Re: 15in vs 12in
« Reply #19 on: April 17, 2014, 11:44:04 am »


Pages: 1 [2] 3   Go Up
 



Page created in 0.064 seconds with 23 queries.