BillFitzmaurice.info

Hello there--
I just joined this forum in the hope of getting some feedback, ideas and hopefully some leads on builders for a cab design concept.

I'm not a builder at all, just a musician who comes up with ideas and gets people to realize them.
Where I am located in Lansing, MI, I don't have anyone currently available who has experience in this field.

I am a solo acoustic performer but also perform with ensembles of diverse instrumentation and volume requirements(acoustic/world/classical/jazz/fusion). I have a fairly simple cab/ext speaker design idea partially inspired by my experience using different amps over the years: Aspen Pittman Spacestation, Bose L1, Acoustic Image, and a fascination with the concept of Johnny Smith's Fountain of Sound amp and Andrew Bird's horn speakers. Although this isn't any of those, it takes inspiration from that.
I need someone to consult with my idea and wondered if I could get your opinions on this--

I try to keep the amount of gear I bring to a gig as minimal as possible (I don't run an entire PA, happy with my Bose L1 model II and Compact for form factor, but in varying ensemble contexts and venues need different projection arrays). Especially when sound needs to be piped out at reverse angles.

In theory, so far this is just a simple ext cab idea that runs from my line out of my amp (Bose or AER etc) or whatever amp I am currently using.

Design is 6 speakers --one on each side of the box and one pointing up towards ceiling(Johnny Smith Fountain of Sound inspired) and one down firing(Acoustic Image inspired). There would be optional screw on legs(a la Fountain of Sound) or you can use an amp stand of some kind.
Simple volume control for each speaker to direct balance towards the angle/band members you need.

Primary goal is to completely avoid beaming in stage contexts as well as address gaps in the projection field. Substitute for additional monitors and PA and to augment the dispersion of a single speaker amp. Also to achieve different sonic results and tune the balance based on position of cab in room.

In my preliminary research this precise thing hasn't been done, or isn't to be found on the market, but please correct me if I'm wrong.
I'm sure the pros will say "it's a bad idea because.." but I'm just curious to have a prototype to try out to see what it does.
The Bose (love 'em or hate 'em) has angled array and the Bill Fitzmaurice XF Guitar Cabs have the 20 degree angle. I'm wondering about the science on speaker angles. In some omnidirectional speaker designs I have seen there is a circular/spherical placement of the speakers. Open to exploring the merits of that. My idea was to keep a standard cab cube but just have access to all the options for speaker output from all the right angles.

Open to speaker brand and type suggestions, but must be optimized for acoustic instruments. Has to be pretty light for transport and this is more of a monitoring solution so no need for huge firepower.
8" might be cool. Maybe 10" for the top and/or bottom?

Anyway, curious to hear your thoughts all!

Thanks

As proposed you'd have massive comb filtering. In order to prevent that the enclosure would have to be circular, with the center to center distance between each driver no more than one wavelength within their pass band. With a woofer that goes to 1kHz that's easy, as 1 wavelength at 1kHz is 1.1 feet. With a tweeter that goes to 12kHz it's not easy, as 1 wavelength at 12kHz is 1.1 inches. You'd need very small tweeters, and a lot of them.

I'll confess I'm not entirely sure what you're after, what problem you're trying to fix. (I find myself with solutions to problems no one has, myself, though. )

Maybe take a look at Don Keele's CBT speakers? With 48 midrange speakers to buy, not exactly a cheap choice at this point in history, but certainly interesting.

https://www.xlrtechs.com/dbkeele.com/CBT.php

Bill's TLAH would certainly be more affordable and more oriented to a pro sound set-up, though.

Hi there.
Welcome to the forum

You description reminds me of a cab that does actually exist,
But its designed exclusively for room acoustic measurements of reverb times and sound transmission to other rooms and such.
https://www.nti-audio.com/en/products/d ... on-speaker

I'm afraid using similar speakers in a live event may cause more problems than they fix, but it would certainly look cool!

Hi all,
Thanks for your replies. Bill--how many tweeters do you think that would take? A spherical design would look cool but funny to transport I guess. Rich4349, to reiterate what I outlined in my post, these are the goals "Primary goal is to completely avoid beaming in stage contexts as well as address gaps in the projection field. Substitute for additional monitors and PA and to augment the dispersion of a single speaker amp. Also to achieve different sonic results and tune the balance based on position of cab in room."

Strange Kevin and Rich4349--the volume control of each speaker I see as a main design advantage. So you can effectively eliminate any speaker that is causing problems and feed the mix more to whichever angle needs more reinforcement. A "tuning" of projection is achieved that way. Uneven and comb filtering, yeah, I guess. But regular guitar amps have that already! LOL

As you all know, using guitar amp cabs creates beaming problems and direction problems. Unless you are right in front you aren't in the sweetspot, but if you are, it might be too loud for you or your bandmates. That's what this design is trying to address, albeit in a small and portable all-in-one cab package for quick set-up and convenience.
NOT hauling a ton of stuff is the goal, so thanks for the links but those speaker designs just look too big. Although I suppose the tech (including Bill's TLAH could be implemented on a small scale?)

Through poking around on forums about the Johnny Smith Ampeg Fountain of Sound amp, I found TOOB cabs. https://www.toob.fi/ Those are designed to be pointed vertically as well. I might try these out for my purposes
Cheers

eldenkellymusic wrote: ↑Thu Apr 28, 2022 9:34 pm As you all know, using guitar amp cabs creates beaming problems and direction problems. Unless you are right in front you aren't in the sweetspot, but if you are, it might be too loud for you or your bandmates.

The usual solution is to put the guitar amp on a tilt-back so that it's aimed directly at the guitarists head, mic the cab, and put it in the main mix through the PA.



However, I acknowledge that possible solutions for that specific issue isn't really what you asked for.

I can kinda get what your get'n at... I think. An all-in-one dealio that will provide main PA out front with some rear facing drivers providing vocal monitoring for the musicians... is that roughly the gist of the quest? Is the physical shape you have in your mind important to achieve, or just something that meets the functional objectives?

Strange Kevin wrote: ↑Thu Apr 28, 2022 9:05 pm You description reminds me of a cab that does actually exist,
https://www.nti-audio.com/en/products/d ... on-speaker

That will have severe comb filtering in the highs for the reason I stated. It will only act as a coherent source where the center to center distance between the adjacent drivers is no more than one wavelength.

Shouldn't a pair of well-designed, well-built, well-placed, well EQed, / limited / crossed over main speakers minimize this unwanted performance?

Beaming frequency (if my quick Gurgling is correct) is inversely proportional to driver size. Bigger drivers start beaming at lower frequencies, smaller at higher ones, right?) If beaming is a perceived issue for you, use / build cabs with more, smaller drivers? You may be delivering more unique sonic performances than many, but why isn't this a more widely discussed problem?

It's not discussed because the average user isn't aware of why it happens. If you don't know what causes it you can't know how to fix it, or prevent it. That's why most of these systems could serve as poster children for how PA systems should not look: https://www.facebook.com/photo/?fbid=51 ... 6382593146

I do know what causes it and how to prevent it, so our cabs are designed accordingly.

Ahh: a local venue! I might have to get up there and see if it sounds "as good as it looks".

Here's my question for this topic:

If someone were to construct a 24" 3012LF T39, with a DR250 on top of that with a slot to accept a Thunderfunk TFB and 1U tuner, and say paired with a RS NYC 20/21 fret...would a seasoned touring bass player coming into the Tucson/Phoenix area rent a rig like that?

A DR250 atop a T39 would likely be the most powerful rig he's ever heard. But you probably wouldn't have any interest in someone renting it, not fitting into the mold of what a bass rig is 'supposed to look like'.

Bummer...Not even with cane grills and a chrome logo?

Only if the logo says 'Ampeg'.

That and the PA guy may hate you for bringing it to the stage