a diagonal 2x12 marshall cabinet?

[bon viesta]

after looking around at ted weber’s website, i found a marshally head based on an orange 120 tube head. it’s called 6o100. i’ve found a bass demo of it on youtube (i’ll link later) and it sounds tight, dirty, fuzzy, and big. and it’s only about 500 bucks. so a marshally head requires a marshally cabinet.

anyways, my first questions about marshall cabinets were founded upon wrong speakers for a too small box, with way too high of a price to actually see any results. i’ve since then learned a little about how to know when a cabinet can have better results with a specific driver depending on the cabinets volume. 4x12 builds are hard to get right, and way too expensive and unpractical to use.

so instead i’ve thought of turning a 412 into a diagonal 212, basing the speakers off of what eminence enclosure sheet (see below) best fits into the volume of the cabinet. less drivers, less weight, less cost, and more space for the drivers to have optimal frequency response. i’ve heard from a thread where someone put two 12s into a 1960 cabinet with two ports that the cabinets are intrinsically middy.

is this worse than what i was asking about a month ago? will it not be any good? should i instead utilize an already built bass cabinet or cabinet design? i’m not going to buy anything for the foreseeable future, i’m looking and thinking about ideas because i’m someone who likes to plan things for a long time before doing anything.

the two volumes are for a 412 cabinet, that can have a 212 diagonal baffle, or a smaller 212 with no need to have a different baffle.

 

[beans-on-toast]

A good sounding 212.

Cab Lab – Ampeg SVT-212AV Bass Cabinet | Bass Gear Magazine

 

[basscooker]

Yes you're better buying a purposefully designed bass cab.

Now with that said:
It's glaringly obvious to any of us who spend time in this subforum that you've caught the build bug in a big way.

I would first ask these questions...
a) what is your status with carpentry skills and tools?

b) do you have some cash that won't break your heart to lose? You will gain some knowledge from the money but may not have anything to show for it otherwise.

c) do you have some modeling software and understand at least the basics of what the graphs tell you?

d) do you already know what sort of voicing you are hoping to get?

e) if you were put on the spot like a reality TV show daily challenge; could you assemble a cube without gaps? This ties to question "a" but knowing how to make a box and actually doing it can be two very different things.

My thoughts:
1. Wait for now on any building, buy a manufactured rig. Find a voicing you want to pursue.

Or

2. Build up a potential throw away project. Start with a very inexpensive woofer (that has full published specs, like an mcm or Dayton). And I mean like an 8" or something. I like mcm# 55-2960. Good high end, cast frame, 20 bucks. Model it up in some software and make all the graphs cooperate with as few compromises as you can. Now can you make the box? How is the driver protected? Can you tolex? Build a grill frame and stretch it straight? Is your offset and inset measured correctly and doesn't have gaps or needing forced in place? How does it sound and are there rattles?

Can't design and build a great cab the first go. Yes you can get amazing results from good plans of a design, but the designer already put in the time and sawdust so you didn't have to. A ground up design will most assuredly have at least 1 prototype or design change before it's golden. Let this happen at low cost first. Use the concepts you learn and adapt to future projects.

Good luck with all of your adventures.

 

[bon viesta]

hm… i’m attempting to amateurishly graph out the frequency response of a legend bp in a box the size of either of the two cabinets. below are my findings, with only speaker in the box. first is the small box, second is the big box.

i’m not exactly sure how to simulate two speakers, and i don’t think that dividing the dimensions by 2 will give an accurate depiction of what each speaker will be dealing with inside the cabinet. the space will be shared, so in theory (to someone with limited understanding of how this stuff works) each speaker will have the ~5 cubic feet of volume all to themselves.

there’s a lot of wonky things going on further down in the frequency chart. if anyone has experience with charts, could you help try to describe what that means/would translate to if i tried to play through it? if it needs to be technical to the point i can’t understand it, than so be it.

 

[basscooker]

You should divide shared airspace by the number of drivers sharing it. As well, if you find a model that looks good for a single driver you need to double it to make a two-driver cab if they share airspace.*


Edit: doubling isn't a hard number there, but yes drivers will perform very differently if what works for one driver is used for two with no increase in space.

 

[basscooker]

About the graphs

IDK what is going on with all that noise above 1K but the 100 and down look decent at first glance.

Note that it says right there at the top that it isn't a recommendation. View it as a representation of where to start tweaking. 5 cuft for a single 12 is pretty roomy. See what happens around 1cuft and tick up in 0.5 cuft increments to around 3.5 cuft; looking at all of the graphs after each change, watching what happens.

 

[bon viesta]

Yes you're better buying a purposefully designed bass cab.

Now with that said:
It's glaringly obvious to any of us who spend time in this subforum that you've caught the build bug in a big way.

I would first ask these questions...
a) what is your status with carpentry skills and tools?

b) do you have some cash that won't break your heart to lose? You will gain some knowledge from the money but may not have anything to show for it otherwise.

c) do you have some modeling software and understand at least the basics of what the graphs tell you?

d) do you already know what sort of voicing you are hoping to get?

e) if you were put on the spot like a reality TV show daily challenge; could you assemble a cube without gaps? This ties to question "a" but knowing how to make a box and actually doing it can be two very different things.

My thoughts:
1. Wait for now on any building, buy a manufactured rig. Find a voicing you want to pursue.

Or

2. Build up a potential throw away project. Start with a very inexpensive woofer (that has full published specs, like an mcm or Dayton). And I mean like an 8" or something. I like mcm# 55-2960. Good high end, cast frame, 20 bucks. Model it up in some software and make all the graphs cooperate with as few compromises as you can. Now can you make the box? How is the driver protected? Can you tolex? Build a grill frame and stretch it straight? Is your offset and inset measured correctly and doesn't have gaps or needing forced in place? How does it sound and are there rattles?

Can't design and build a great cab the first go. Yes you can get amazing results from good plans of a design, but the designer already put in the time and sawdust so you didn't have to. A ground up design will most assuredly have at least 1 prototype or design change before it's golden. Let this happen at low cost first. Use the concepts you learn and adapt to future projects.

Good luck with all of your adventures.

wow! you’ve given me a lot to work with.

carpentry skills are close to none, cash is about to be delivered via selling some old cymbals i don’t use anymore for about 500+ bucks, and i have little understanding of graphs and what exactly they’re saying. i do understand at least that they should be smooth.

the voicing i look for is particularly mid and low mid based. no desire for high end, and no desire for blasting low end. very middy.

as for your box challenge, maybe give me a few weeks to learn how to use do good carpentry

i don’t know if i’d ever want to actually build a box from scratch. maybe if it’s simple, and if i plan beforehand thoroughly learn how to do so, but not under many other conditions.

thanks for the advice. i’ll try to look around a lot more for designs and bass cabinets.

 

[abarson]

I've said it before and I'll say it again, build a kit first, or at minimum use well-established plans like the BFM Simplexx or Greenboy fEarful. That way you get some familiarity with building a cabinet but have a better chance of ending up with a useable outcome. You can do either one in a finish that meets your aesthetic goal.

Bass Guitar DIY Speaker Kit (speakerhardware.com)
fEARful DIY Speaker Kits for Bass Guitar (speakerhardware.com)
Simplexx (billfitzmaurice.info)

Design takes time, patience, and trial-and-error. I was short on all three when I did my first build and got comparable results.

 

[Passinwind]

About the graphs

IDK what is going on with all that noise above 1K but the 100 and down look decent at first glance.

It looks suspiciously like a gated actual measurement above about 250Hz grafted to a modeled response curve below that. Not an uncommon approach really.

 

[basscooker]

Lol 250
I really need glasses. And the attention span to zoom.

 

[bon viesta]

It looks suspiciously like a gated actual measurement above about 250Hz grafted to a modeled response curve below that. Not an uncommon approach really.

does this mean that whatever comes after that slope is just not really anything you’d ever hear from the speaker? does it matter?

 

[bon viesta]

About the graphs

IDK what is going on with all that noise above 1K but the 100 and down look decent at first glance.

Note that it says right there at the top that it isn't a recommendation. View it as a representation of where to start tweaking. 5 cuft for a single 12 is pretty roomy. See what happens around 1cuft and tick up in 0.5 cuft increments to around 3.5 cuft; looking at all of the graphs after each change, watching what happens.

that 5 cubic feet is for 2 12-inch speakers to live. not sure how to translate that to the simulator. i’ve divided the dimensions all by half and the frequency response looked absolutely ridiculous, so i think doing that may have been an inaccurate representation of two 12 inchers in 5 cubic feet.

i also divided the height by half and that made a more reasonable looking frequency response, but this isn’t a divided cabinet so i don’t know if i can expect that to be accurate to what would happen inside the cabinet either.

 

[Passinwind]

does this mean that whatever comes after that slope is just not really anything you’d ever hear from the speaker? does it matter?

Many measurement apps have a curve smoothing option, and you're usually probably better off looking at that smoothed curve IME and IMO. Box tuning is pretty much all about the lows and low mids anyway.

 

[JKos]

Fyi, there is a Marshall 2x12 cab which is 4x12 size with speakers on the diagonal. I had one. Model number 1961A.

I played guitar at the time. Best sounding Marshall cab I ever played.

 

[micguy]

If you put speakers on a diagonal on a baffle, the dispersion will be asymmetrical. What that means is if you move around left and right, with your ears naturally above the plane of the thing, it'll sound quite a bit different if you go to the left than it will if you go to the right. Now the real question - which way do your slant it? That depends on a lot of factors, such as which side the drummer will be on w.r.t. your cabinet - he or she will hear you better on one side than the other.

 

[JKos]

If you put speakers on a diagonal on a baffle, the dispersion will be asymmetrical.

Having played the above mentioned Marshall cab, in real life, I did not hear this happening at all. It actually had a much more consistent sound and better dispersion than a regular 4x12.

 

[micguy]

Having played the above mentioned Marshall cab, in real life, I did not hear this happening at all. It actually had a much more consistent sound and better dispersion than a regular 4x12.

It would disperse more than a square array in general, as it isn't beaming in 2 axes, but the beaming at mid frequencies is definitely asymmetrical - the Physics can't really be suspended. If you're playing in a reverberant place (basement or a small club), it might easily be swamped by everything else bouncing around, but on an outdoor stage, it'd be quite noticeable.

 

[bon viesta]

It would disperse more than a square array in general, as it isn't beaming in 2 axes, but the beaming at mid frequencies is definitely asymmetrical - the Physics can't really be suspended. If you're playing in a reverberant place (basement or a small club), it might easily be swamped by everything else bouncing around, but on an outdoor stage, it'd be quite noticeable.

why do so many 212 cabinets have a diagonal design if their uneven dispersion is such a noticeable and bad thing? it’s far more common than the diagonal 212 cabinet, if my memory serves.

 

[micguy]

why do so many 212 cabinets have a diagonal design if their uneven dispersion is such a noticeable and bad thing? it’s far more common than the diagonal 212 cabinet, if my memory serves.

Because people want 10 pounds of speaker in a 5 pound bag, and that's how you squeeze it in - a vertical 212 is taller, and more cumbersome to move around. Why do almost all commercially available bass guitar cabinets do a poor job of reproducing the fundamentals of a bass, to where people have to high pass their signals to avoid driving the speaker past its excursion limits and sounding muddy? Same basic answer - people want small, light and loud - when you demand that, clean, linear low frequency bandwidth gets nixed by the Physics in the thing. In both cases, it's a compromise that sells - performance isn't the thing that matters most sometimes.

 

[Prana Ferox]

It looks suspiciously like a gated actual measurement above about 250Hz grafted to a modeled response curve below that. Not an uncommon approach really.

does this mean that whatever comes after that slope is just not really anything you’d ever hear from the speaker? does it matter?

When you measure a speaker with a regular-ish microphone (as opposed to sorcery like a Klippel) you need to isolate the directly transmitted sound from any reflections off the floor, walls etc. You can do this by having crazy anechoic chambers etc or you can 'gate' the measurement time to catch the initial burst and stop before any echoes arrive. Because lower frequencies have longer cycle times, this only works down in frequency to a certain point. So actually measuring low end frequency response independent of room interactions can be a pain.

On the other hand low frequencies are less affected by diffraction, cone breakup, all the little things that make higher end FR so squiggly. And LF response derivation via Thiele-Small parameters is an understood and fairly simple thing. So what passinwind is saying is they took actual measurements for HF and simulated response for LF and stuck them on the same chart.

In re diagonal 12s, music cabs have a lot of other constraints like, can a normal human's arms reach the handles, where is the center of mass, will a standard-ish tube head fit on top, will it fit in a car door or trunk etc. Many common multiple-driver cabs have suboptimal driver arrangements for comb filtering and dispersion because they were just lower priorities, and in live music there's so much other audio crap going on. Any time you have drivers arranged horizontally, especially parallel to / lying on the floor you're gonna have weird interference things. So a diag 2x12 in roughly the same box dimensions as a 4x10 is good enough for most. Nevertheless if I were building a 2x12 (and I don't are about sticking a big tube amp or rack pm top) I'd build a Chris Cole slant cab or something on similar lines.

 

[bon viesta]

When you measure a speaker with a regular-ish microphone (as opposed to sorcery like a Klippel) you need to isolate the directly transmitted sound from any reflections off the floor, walls etc. You can do this by having crazy anechoic chambers etc or you can 'gate' the measurement time to catch the initial burst and stop before any echoes arrive. Because lower frequencies have longer cycle times, this only works down in frequency to a certain point. So actually measuring low end frequency response independent of room interactions can be a pain.

On the other hand low frequencies are less affected by diffraction, cone breakup, all the little things that make higher end FR so squiggly. And LF response derivation via Thiele-Small parameters is an understood and fairly simple thing. So what passinwind is saying is they took actual measurements for HF and simulated response for LF and stuck them on the same chart.

In re diagonal 12s, music cabs have a lot of other constraints like, can a normal human's arms reach the handles, where is the center of mass, will a standard-ish tube head fit on top, will it fit in a car door or trunk etc. Many common multiple-driver cabs have suboptimal driver arrangements for comb filtering and dispersion because they were just lower priorities, and in live music there's so much other audio crap going on. Any time you have drivers arranged horizontally, especially parallel to / lying on the floor you're gonna have weird interference things. So a diag 2x12 in roughly the same box dimensions as a 4x10 is good enough for most. Nevertheless if I were building a 2x12 (and I don't are about sticking a big tube amp or rack pm top) I'd build a Chris Cole slant cab or something on similar lines.

so basically, that burst of high frequency isn’t going to sound like a searing flash of “eeee” or anything else unpleasant like that from the actual speaker? it’s just the simulation (or actually, it seems to be actual real life recorded measurements if i’m understanding you correctly) of a room interacting with the low frequency?

and it seems to shorten or widen or change that measurement of room interaction based on the enclosures dimensions because i’m guessing the whole thiele-small thing includes some kind of way to predict how the room may change its interaction based on the enclosure size.