Newbie here so go easy. Let me start by explaining the motivation behind what I'm doing, maybe a few people will be familiar with it. I'm looking to design a stage monitor to be used by guitarists playing through a digital modeling device. Nowadays, these devices are quite high end and used by many in lieu of the traditional setup of a tube amplifier into a cabinet of 1-4 12" woofers. (Response is quite narrowband, about 70 Hz to 8000 Hz at a stretch.) The sound of these speaker cabinets is captured as an impulse response (recorded through a variety of mics) which can be convolved with the output of a digital amp simulation to produce a final result that is very similar to that of a mic'd guitar amp. This signal can be fed into a full range system (studio monitors, PA/FOH, etc). For reference, here's a typical 4x12 guitar cab.
The problem with this approach is that the sound of a mic'd guitar amp is not actually what many players are looking for. It would be preferable for the monitor to create an experience that is closer in nature to standing next to traditional guitar amp, described as "amp in the room" feel. There are several products on the market that try to accomplish this, and the one of interest today for this project is the Friedman ASM-12, which is actually a modified B-52 ACTPRO 12M stage monitor.
I have no background in speaker system design, so hopefully I'm not talking complete nonsense here. It seems like the reason that Friedman's product works well for guitarists is the unusual choice of an enormous round horn-loaded HF driver. Maybe someone can chime in on why this arrangement works - the "guitarist" explanation is that the horn being similar in size and shape to the 12" woofer makes for something that acts more like a guitar cabinet, which is probably nonsense. Point is, I want to build something similar. Turns out PE sells a very similar horn, so I looked around and cobbled together some candidate parts:
Dayton Audio H10RW 10" Round Waveguide 1-3/8"- 18 TPI
Selenium D250-X GW 1" Phenolic Horn Driver 1-3/8"-18 TPI
Eminence Delta Pro-12A 12" Cast Frame Driver
Dayton Audio XO2W-2K 2-Way Speaker Crossover 2,000 Hz
From modeling, it looks like I'm aiming for 3.0 ft³ vented and tuned to about 50 Hz. I'm planning to amp this box externally off a Behringer iNuke DSP or similar. All that said:
- Does this whole project make sense, in broad terms? Am I on the right track here, or making newbie mistakes?
- Should I look at a different woofer? I figure you can't go wrong with a Delta Pro, but I thought I'd ask as it's somewhat heavy and expensive for a woofer I'm crossing at 2k.
- How about the choice of horn driver? This one is unusual in that it's a phenolic driver that only reaches to 9k. But guitars don't extend past that, and I thought the sound of phenolic might be more flattering to guitars.
- How do you level match the woofer and horn?
All other comments are welcome. I fully acknowledge being beyond my depth here.
The problem with this approach is that the sound of a mic'd guitar amp is not actually what many players are looking for. It would be preferable for the monitor to create an experience that is closer in nature to standing next to traditional guitar amp, described as "amp in the room" feel. There are several products on the market that try to accomplish this, and the one of interest today for this project is the Friedman ASM-12, which is actually a modified B-52 ACTPRO 12M stage monitor.
I have no background in speaker system design, so hopefully I'm not talking complete nonsense here. It seems like the reason that Friedman's product works well for guitarists is the unusual choice of an enormous round horn-loaded HF driver. Maybe someone can chime in on why this arrangement works - the "guitarist" explanation is that the horn being similar in size and shape to the 12" woofer makes for something that acts more like a guitar cabinet, which is probably nonsense. Point is, I want to build something similar. Turns out PE sells a very similar horn, so I looked around and cobbled together some candidate parts:
Dayton Audio H10RW 10" Round Waveguide 1-3/8"- 18 TPI
Selenium D250-X GW 1" Phenolic Horn Driver 1-3/8"-18 TPI
Eminence Delta Pro-12A 12" Cast Frame Driver
Dayton Audio XO2W-2K 2-Way Speaker Crossover 2,000 Hz
From modeling, it looks like I'm aiming for 3.0 ft³ vented and tuned to about 50 Hz. I'm planning to amp this box externally off a Behringer iNuke DSP or similar. All that said:
- Does this whole project make sense, in broad terms? Am I on the right track here, or making newbie mistakes?
- Should I look at a different woofer? I figure you can't go wrong with a Delta Pro, but I thought I'd ask as it's somewhat heavy and expensive for a woofer I'm crossing at 2k.
- How about the choice of horn driver? This one is unusual in that it's a phenolic driver that only reaches to 9k. But guitars don't extend past that, and I thought the sound of phenolic might be more flattering to guitars.
- How do you level match the woofer and horn?
All other comments are welcome. I fully acknowledge being beyond my depth here.
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Hi. Fascinating project. Understand I am talking out my a$$ here but to give you feedback (it IS for electric guitar after all.)
Assume your guitar modeling DSP and amp are perfect. What the guitarist actually hears is a cabinet and the speaker and the Box resonances which I assume are tiny and swamped by driver output. The biggest control you will have is over the driver and enclosure. It seems to me you would want the most generic flattest response. I am assuming all the distortion and frequency anomalies will be supplied by the DSP. As far as power and dispersion of the enclosure, that should match the generic speaker box. At least, from the outside, I would say you want to design a widest dispersion very flat very low Distortion guitar cabinet, which is the antithesis of all rock Pro gear I've ever heard of. 😄
Assume your guitar modeling DSP and amp are perfect. What the guitarist actually hears is a cabinet and the speaker and the Box resonances which I assume are tiny and swamped by driver output. The biggest control you will have is over the driver and enclosure. It seems to me you would want the most generic flattest response. I am assuming all the distortion and frequency anomalies will be supplied by the DSP. As far as power and dispersion of the enclosure, that should match the generic speaker box. At least, from the outside, I would say you want to design a widest dispersion very flat very low Distortion guitar cabinet, which is the antithesis of all rock Pro gear I've ever heard of. 😄
Thanks for chiming in. You're correct that low distortion linear is better, but dispersion is a bit tricky. A standard guitar cab has terrible dispersion characteristics, with a massive off-axis shift in response. It's not clear to me whether or not this shift is a good thing or not. There's another product on the market (Atomic CLR) that uses a coaxial arrangement, and is clearly designed not to shift tone so sharply off axis. Since I don't know myself what the correct approach is, I'm stuck copying what I see out there.
here's a $30 PRV cousin's response on a rectangular waveguide using 15uF - a second order highpass might make it look better on the low end
I probably have the 12" Dayton waveguide - in contrast, the little K700 Kipsch horn has more on axis beaming and a bit hotter on axis from 5-9K
3 cubic foot sounds kinda large for the woofer - ar you doing drop tunings?
my hands have gone numb - no guitar or bass anymore
your project seems like a nice idea to maintain timbre off axis
I probably have the 12" Dayton waveguide - in contrast, the little K700 Kipsch horn has more on axis beaming and a bit hotter on axis from 5-9K
3 cubic foot sounds kinda large for the woofer - ar you doing drop tunings?
my hands have gone numb - no guitar or bass anymore
your project seems like a nice idea to maintain timbre off axis
fwiw here's the PRV D250ph version on - 12" Dayton round waveguide, Pyle 612 rectangular waveguide, and the little old-school exponential K700 Klipsch rectangular mouth horn - highpass = 6.8uF/ 0.56mH
I get the idea old school pea-shooter horns with longer path than these modern CD waveguide, have more - or more even low end loading,
maybe a proper crossover will make the response better - if that would matter for guitar use
I get the idea old school pea-shooter horns with longer path than these modern CD waveguide, have more - or more even low end loading,
maybe a proper crossover will make the response better - if that would matter for guitar use
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