Question about Bass Cab Speaker Pairing / Dimension / math etc.

[KevInDaBassment]

...I can send the speakers back. I have a 30 day money back warranty at Thomann, this is not the case. But I need to know if the speakers can handle being pushed in that enclosure... So would need someone who can do the maths....

If the speakers are damaged I'll venture they won't take them back

This equivalent to dropping a post in the Luthiers Corner asking about the math behind creating a glass bass neck....then complaining and demanding they tell you how to spec out the neck, whilst they tell you it's a unilaterally bad idea.

At this point you're set on an experiment, with a cabinet that works for bass being an afterthought. At that point, buy whatever 12" speakers you want and just throw 'em in. Just be sure to read the fine print on Thomann's return policy

 

[raketenmann]

If the speakers are damaged I'll venture they won't take them back

This equivalent to dropping a post in the Luthiers Corner asking about the math behind creating a glass bass neck....then complaining and demanding they tell you how to spec out the neck, whilst they tell you it's a unilaterally bad idea.

At this point you're set on an experiment, with a cabinet that works for bass being an afterthought. At that point, buy whatever 12" speakers you want and just throw 'em in. Just be sure to read the fine print on Thomann's return policy

That is exactly my point - sorry, probably my english isn't good enough. I don't have the idea to randomly do this experiment and cause the speakers to fail. I won't do so.

And no - i don't think it is the same. As I mentioned before, I would like to know the maths behind it. In this case it is all about the maths. I don't try to put speakers into a refrigerator. It is a cab with a certain proportion. It could work or not. Only the maths will tell for certain if it will or not....

 

[dbsfgyd1]

Yes, I know it is not cost effective - that was never the idea. The idea is to keep a nice cab that looks cool and get some use out of it. If this is not possible, then I will not do so. But at the moment I am looking for a clear statement, not "chances are high it won't work" - if it is possible to match a speaker to a specific cab, it should be possible to match my cab to a certain speaker - doesn't it. I would like to learn something about this process.

OK, so I see the volume alone is not all that matters... I could measure the distance from the speakers, no problem....

"I could measure the distance from the speakers, no problem" which may require modification to the cab where the speaker are currently located. You must really love this cab. Lol!!

 

[blr2]

EDIT: As I mentioned before: If it is possible to design a cab around a speaker it should be doable to reverse engineer it? I

Theoretically, yes, but you'll have to find the right speaker, which is always the one that the cab was designed for.
If you can return the speakers, go ahead, try it and share your impressions with us.

 

[raketenmann]

"I could measure the distance from the speakers, no problem" which may require modification to the cab where the speaker are currently located. You must really love this cab. Lol!!

ehm, no I don't mean that I would modify the distance from the speakers on the baffle. I mean if someone is willing to do the calculations, then I could provide the data. No, I wouldn't go that far and create a new baffle board.

 

[KevInDaBassment]

As I posted in the latest post, I don't know what parameters these are, but Celestion provides some information for that speaker:

PULSE12 - Celestion

These 200W 12 inch bass guitar speakers by Celestion deliver an ideal combination of responsiveness and rock solid low end.

celestion.com

Yup, exactly what I suggested

Well, not exactly - or not as I would put it. You've ever seen a VW Beetle rolling by with an E-Motor? Makes absolutely no sense. But it has style!



EDIT: As I mentioned before: If it is possible to design a cab around a speaker it should be doable to reverse engineer it? I just don't know how to do that, but is it really that complicated for the people that know how to do that?

That's not even close to understanding my analogy lol

The point is both Diesel and Regular Unleaded fuel are fossil fuels, so if you have a gas car some might assume "Hey, both of these are fossil fuels, it should work since that's what my car engine runs on!" However this is far from the case and the Diesel will harm your car engine.

You sort of understand that point (just aren't applying said wisdom), but you're asking "Well, how do I modify and redesign this engine to accept Diesel fuel?" The disconnect here for you is that doing that attempting the engine redesign is going to introduce more issues, be less efficient, and will probably cost more than a new car to do the redesign.


That's what everyone is trying to tell you, it's far more complicated and likely you won't find anything that works with that cabinet anyways. And that's just preventing the speakers from getting messed up, we're not even touching on whether it'll sound good. This is a common thing we see in posts on here, somebody has their heart set on something and they are really seeking affirmation, instead of information. You'll get better results buying a single 12" or 15" bass combo than whatever you're attempting with the guitar cabinet. At this point I'd even suggest a TC Electronic combo

 

[raketenmann]

Theoretically, yes, but you'll have to find the right speaker, which is always the one that the cab was designed for.
If you can return the speakers, go ahead, try it and share your impressions with us.

No, I won't try

Yup, exactly what I suggested

That's not even close to understanding my analogy lol

The point is both Diesel and Regular Unleaded fuel are fossil fuels, so if you have a gas car some might assume "Hey, both of these are fossil fuels, it should work since that's what my car engine runs on!" However this is far from the case and the Diesel will harm your car engine.

You sort of understand that point (just aren't applying said wisdom), but you're asking "Well, how do I modify and redesign this engine to accept Diesel fuel?" The disconnect here for you is that doing that attempting the engine redesign is going to introduce more issues, be less efficient, and will probably cost more than a new car to do the redesign.


That's what everyone is trying to tell you, it's far more complicated and likely you won't find anything that works with that cabinet anyways. And that's just preventing the speakers from getting messed up, we're not even touching on whether it'll sound good. This is a common thing we see in posts on here, somebody has their heart set on something and they are really seeking affirmation, instead of information. You'll get better results buying a single 12" or 15" bass combo than whatever you're attempting with the guitar cabinet. At this point I'd even suggest a TC Electronic combo

Sure I understand your analogy. I don't see why my analogy isn't a funny but also an appropriate analogy as well. Putting an E-motor into a VW Beetle is a) not cost effective b) the issues of e.g. chassis are not solved - that's why I said. I did see a VW beetle with an E-Motor and I just thought how ridiculous that is - but also how cool it was.



but let's skip the argument. In the end I do get the point. I wrote in the first post, that you all will try to tell me that it is not a good idea. I do know that it is not a good idea. But still, I am interested in the maths...

 

[raketenmann]

Yup, exactly what I suggested

What do you mean by that?

 

[Michedelic]

Deal Community

I know that probably a lot of you will argue that my plans are no good, but still I am trying to figure out if it could work or not

I am a guitar player that plays sometimes bass. I like old school sounds, nothing super deep modern. I like Ampeg or Orange Bass tones. So I have this old Carlsbro Cab fom the late 60ies that was built for guitar, a Tall 4x12 cab, which is oversized and way bigger than a regular Marshall 4x12. I would like to convert it to a bass cab - the speakers need to be replaced and I have no use for another guitar cab, but I love that cab for its style, therefore I would like to keep it and probably use it sometimes for bass tone. I know, it is likely not to be eathshaking and for most of modern bass players not satisfying - but as we all know Lemmy also played a 4x12 cab and had a tone that at least some bass players find adorable.
So I would liket to but in 4 Celestions Pulse 12, making the cab an 8 Ohm 800 watt cab.

I am just wondering if this will be a somewhat working pairing for my needs? I know some speakers are not made to be used in closed cabs, but I think the Pulse 12 can do that.

The inside dimensions of the cab would be 280mm deep, 725mm wide and 915mm high.

What are your thoughts? I am very curious!

Looking like this?

Oh, that would definitely be "old school", as in a Jack Bruce/Andy Fraser sound. Nothing I have any use for. But even retrofitted with bass appropriate drivers, I don't think those Marshall-esque cabs are deep enough, if by some miracle the internal box volume matched the parameters.

 

[raketenmann]

Looking like this?
View attachment 7319319View attachment 7319320

Oh, that would definitely be "old school", as in a Jack Bruce/Andy Fraser sound. But even retrofitted with bass appropriate drivers, I don't think those Marshall-esque cabs aren't deep enough, if by some miracle the internal box volume matched the parameters.

jup, exactly this one!

 

[blr2]

I do know that it is not a good idea. But still, I am interested in the maths...

Then, instead of wasting time here, spend couple of hours on the internet, you'll get a pretty good idea. AFAIK, there is some free software available, as well.

 

[raketenmann]

So probably someone can help me with this calculator here:

Lautsprecher Gehäuseberechnung mit Thiele Small Parameter

Lautsprecher-Gehäuseberechnung mit dazu gehöriger Übertragungsfunktion, Sprungantwort, Gruppenlaufzeit und Schwingspulenimpedanz

www.micka.de

I know all the thiele smalls parameters, only Rg in Ohms I don't know. Can someone explain what that is?

Probably someone can show me another calculator in english where I can make calculations for a non-bassreflex-cab

 

[raketenmann]

Then, instead of wasting time here, spend couple of hours on the internet, you'll get a pretty good idea. AFAIK, there is some free software available, as well.

Yes, Probably I will do so. I just thought someone here is super skilled and can put in the parameters into a calculator easily

 

[KevInDaBassment]

What do you mean by that?

Starting with the speaker to find what parameters work with them, which was my initial suggestion

Sure I understand your analogy. I don't see why my analogy isn't a funny but also an appropriate analogy as well. Putting an E-motor into a VW Beetle is a) not cost effective b) the issues of e.g. chassis are not solved - that's why I said. I did see a VW beetle with an E-Motor and I just thought how ridiculous that is - but also how cool it was.



but let's skip the argument. In the end I do get the point. I wrote in the first post, that you all will try to tell me that it is not a good idea. I do know that it is not a good idea. But still, I am interested in the maths...

Putting an electric motor in the VW won't cause damage to the engine, it just won't go very far. I agree it won't be very efficient, but people would understand there is a big difference there between a gas and electric engine intuitively.

The Diesel/Gas analogy is to explain it seems like a trivial feat to make the gas engine use Diesel, but it's not and can be downright dangerous. I can't speak for everyone here, but I'm just trying to save you the trouble of this project by giving you an example of how vast of a task it is to pull this off.

It's hard to convey over the internet, but the input from everyone is genuinely trying to be helpful at its core. There's a lot of projects folks took on before Talkbass was around and they REALLY regretted it later (lots of money lost too, I bet). We're just trying to help you steer away from something that could be a massive, expensive headache for you in the long run.

I get the experimentation bug from time to time as well. Months ago I wanted to jump into pedal modification or kit building, but I'm nowhere near wanting to make a career of that and the cost to buy from a builder or used was a better use of my $$ and time. YMMV, if you've got a few hundred to burn go for it and see how it pans out. At the end of the day, it's your gear and your money, nobody can force you to do anything with it you don't want to....except the government

 

[blr2]

Yes, Probably I will do so. I just thought someone here is super skilled and can put in the parameters into a calculator easily

You don't need to be super skilled to put a set of parameters into online calculator. Just do it and see how far you enclosure is from the suggested dimensions.
Just as a rough prediction: If too big the cab will sound boomy and you run the risk of damaging the drivers if you exceed max. excursion limit. Difficult, but not impossible to do it, even in a sealed cab.
If too small, the cab will sound boxy and lacking proper low end.

These are just estimates. There are other things that may influence the sound, that cannot be predicted from simple calculations. The cab may need bracing and/or acoustic treatment, for instance.

 

[WRM]

Looking like this?
View attachment 7319319View attachment 7319320

Oh, that would definitely be "old school", as in a Jack Bruce/Andy Fraser sound. Nothing I have any use for. But even retrofitted with bass appropriate drivers, I don't think those Marshall-esque cabs are deep enough, if by some miracle the internal box volume matched the parameters.

Wow - look at all of that internal bracing! Mesa Boogie must be wasting a lot of extra material on their Subway Cabs, if that is "good enough"?...


@raketenmann , good luck in your adventure, please let us know what you decide and how it turns out. If it is a serviceable Guitar Cab, I would leave it alone....

 

[agedhorse]

It's possible to reverse engineer but that involves choosing the right driver for an existing cabinet since you already have the cabinet.

 

[raketenmann]

It's possible to reverse engineer but that involves choosing the right driver for an existing cabinet since you already have the cabinet.

OK - of course I am open to other speaker suggestions. This was just a cheap one and somewhere it says it is built for use in closed cabs.

If you have any tip for a calculator and what I need to put into a calculator for my existing cabinet, I could try that out.

 

[raketenmann]

I get the experimentation bug from time to time as well. Months ago I wanted to jump into pedal modification or kit building, but I'm nowhere near wanting to make a career of that and the cost to buy from a builder or used was a better use of my $$ and time. YMMV, if you've got a few hundred to burn go for it and see how it pans out. At the end of the day, it's your gear and your money, nobody can force you to do anything with it you don't want to....except the government

Haha - that's why I already built my own tube amp - and also did a repair job on an old 70ies modified english tube amp no tech wanted to lay his hands on It did work out, more than just sufficient.

but still you got me wrong: I am not up to wasting money and blow up some speakers. I won't do so. I would only do it if the maths show that it could work. And then decide if I can live with the sound or not. Nothing else. But so far noone was able to show me how to do the calculations, so I will try to figure that out by reading through the internet.

 

[blr2]

Haha - that's why I already built my own tube amp...

You built a tube amp and you cannot run an online T/S calculator?!