How do cabs even work?

[mayoayox]

whats the baffling do? how does that all affect the tone? i can read schematics but i still dont really understand physical sound design after the signal leaves the amp

Prompted by a five watt world video on the Ampeg B15

I can watch videos comparing 4x10 vs 1x15 or closed vs open back, but I still have a hard time with some vocabulary words like Baffling, and how that affects anything. I've also seen intricate double box designs from people building for their cars sound system -- how does sound travel through a box like that?

I might have a hard time understanding in text, but ive tried Google and YouTube and searching this forum. ANY help is appreciated, but a YouTube video is doubly so.

 

[lug]

Beware that there’s a lot of bull-poopie being passed off as legitimate technical information, especially on audio influencer social media sites (including videos).

This gets in the way of understanding what’s really happening because they are production a convincing manner (including AI use).

When I design a new speaker system, I try to incorporate chili power. Makes the speaker kick like a 12 gauge!

 

[Topkat13]

Call one and tell the driver where you need to go.

 

[agedhorse]

When I design a new speaker system, I try to incorporate chili power. Makes the speaker kick like a 12 gauge!

I thought about a line of speakers... like Picante 115

 

[5StringBlues]

Tide goes in, tide goes out. You can't explain it.

 

[OldogNewTrick]

without light, it's much harder reading at bedtime...

For light bedtime reading....

https://bassisttech.github.io/SpeakerTheory/speakerTheorySympy.pdf

Francis, I actually took the time to read your paper.
With light, thanks to my back-lit laptop screen.
I admit, I skipped over the too difficult bits, so maybe I didn't read all that much...
But still... I do appreciate the clear and concise way you wrote the paper. It did help me to get a (somewhat) clearer understanding of the physics at work.

 

[S-Bigbottom]

Just a side note, don't use any "4x10 vs 1x15 comparison on YouTube", to make any real decisions on which behaves this or that way. When recording a speaker enclosure there are so many factors like microphones and the room itsself, and maybe even post editing that the viewers have no idea on. I'd say videos on bass speaker cabinets are rarely very representative to the real life experience.

Darn Right!
There is the sound or tone your computer or headphones can kind of give. But in the room it is the THUMP and FEEL of moving air that a phone, computer speakers, headphones and even a good home hifi system cannot replicate.

 

[Sharko]

The basics are pretty easy to learn and understand if you have a technical mind with a bit of mathematical knowledge.

It’s an often mocked lyric from an ICP song, but thanks I’ll look into it

 

[iqi616]

Darn Right!
There is the sound or tone your computer or headphones can kind of give. But in the room it is the THUMP and FEEL of moving air that a phone, computer speakers, headphones and even a good home hifi system cannot replicate.

I came here to say that. The only way to evaluate cabinets is to be there.

 

[erratick]

For light bedtime reading....

https://bassisttech.github.io/SpeakerTheory/speakerTheorySympy.pdf

Is there access for the juypter notebook?

Going to look up the dickason book.

 

[Wyvern]

Open bottom port cabs sound open, sealed cabs sound compressed, single port cabs sound like closed cabs with more sub-bass response.

Small cabs sound more middy, oversized cabs tend to have less bass and more openess.

10's sound flat (even) 12's have a "V" shape usually (enhanced lows and highs) 15” have more high mids and woofy lows.

Of course it all depends on speakers, cab construction and crossovers if we are talking multi-driver cabs.

My favorite is a 212 in a diagonal bottom port cab with a tweeter.

 

[agedhorse]

Open bottom port cabs sound open, sealed cabs sound compressed, single port cabs sound like closed cabs with more sub-bass response.

Small cabs sound more middy, oversized cabs tend to have less bass and more openess.

10's sound flat (even) 12's have a "V" shape usually (enhanced lows and highs) 15” have more high mids and woofy lows.

Of course it all depends on speakers, cab construction and crossovers if we are talking multi-driver cabs.

My favorite is a 212 in a diagonal bottom port cab with a tweeter.

Factually, one of this is consistent with my 40 years of professional speaker design. This sounds like you got some (inaccurate) AI assistance with these statements of "fact".

The only thing indisputable is your preference for what you like personally.

 

[fdeck]

Francis, I actually took the time to read your paper.
With light, thanks to my back-lit laptop screen.
I admit, I skipped over the too difficult bits, so maybe I didn't read all that much...
But still... I do appreciate the clear and concise way you wrote the paper. It did help me to get a (somewhat) clearer understanding of the physics at work.

Thanks! I hoped that my article could be read in two different ways: 1) Skip the equations and code, but enjoy the text and graphs. 2) Dig into the equations and even use them.

There's physics and math, but not a huge amount, and you can see just how much there is. A few laws from freshman physics, and a calculus trick that's familiar in engineering.

Is there access for the juypter notebook?

Going to look up the dickason book.

The notebook is here:

bassistTech.github.io/SpeakerTheory at main · bassistTech/bassistTech.github.io

Contribute to bassistTech/bassistTech.github.io development by creating an account on GitHub.

github.com

My article mainly focused on getting to the bottom of where the modeling programs come from, but is light on advice about how to make something that actually sounds good and survives its use.

 

[Promit]

I had the idea to do this as a story, and we start with our protagonist- a simple speaker. Imagine a 15” woofer perhaps. We give this speaker some signal, and it makes sound. Great! But something is not quite right. There’s no bass. Acoustically, a speaker has no front or back. The waves coming out either side of the speaker are meeting each other and canceling out. We can stop the waves from meeting by putting a barrier between them, a flat board called the speaker baffle. But the waves still reach around the edges. It would really be better if we had only one wave, not two. So we put the speaker and its baffle into a box, containing the second wave, and now our speaker cab is complete. An attentive experimenter notices that the size of the box changes how the speaker sounds, and this is a useful adjustment method. The bass heads find that adding more speakers to a bigger box is more powerful and pleasing, as long as someone’s around to move it.

But in fact, eventually someone notices that although our woofer now makes copious bass, other frequencies have shifted. That second wave we locked inside the box yearns to be heard, and it’s pushing on the cab and the speaker. That’s not ideal. Bracing on the cab helps it resist the pressure of the speaker’s extra back wave, and absorbing materials lining the cab reduce the pressure of those waves. With those additions, we now have a lovely sealed speaker cabinet.

Hang on, says our enterprising designer. Instead of aggressively containing this wave, could we do something with the wasted extra energy? A cutout in the back of the cabinet has interesting results, with big room filling sound. Sounds a little odd for bass but the guitarist seems to love it. What if the leaking wave was more controlled? The designer discovers that if the hole is a tube, the back wave becomes focused to a smallish range of bass frequencies, and the resulting boost can be tuned by the number and dimensions of those tubes. Bass heads marvel at the resulting power of the “vented” or “ported” cab.

I’m not doing tweeters and crossovers. Fin.

 

[agedhorse]

Actually, it's not as much as the sound inside the box "wants to be heard", it's much more that this energy is part of the resonant spring-mass system of the driver + enclosure. Because this energy is used (both constructively and destructively), it effectively steals from Peter to pay Paul.

This is exactly the same concept that happens with any active filter, and the Q function of the filter. In fact, this is EXACTLY what Thiele and Small discovered as they developed and refined the TS-Parameter formulas and calculations. Modern speaker modeling is based on electronic feedback filter equations.

 

[Al Kraft]

Tide goes in, tide goes out. You can't explain it.

You can explain it with math and science, but IME it's a lot less fun that just watching the tide during a day at the beach.

 

[bass player 53]

You can explain it with math and science, but IME it's a lot less fun that just watching the tide during a day at the beach.

Sir Isaac Newton was the first to successfully explain ocean tides as a direct result of the gravitational attraction of the moon and the sun. He published this groundbreaking mathematical explanation in his 1687 masterpiece, the Philosophiae Naturalis Principia Mathematica. [1, 2, 3]

I give him

 

[Hoochie Coochie Man]

Agedhorse said: "Because this energy is used (both constructively and destructively), it effectively steals from Peter to pay Paul".

I say if you steal from Peter he is likely to get awfully sore, and we all know it's no fun trying to do business with a sore Peter.

 

[6thplanet]

I still have his book sitting at the head of my bed just to review every once in a while, and I more or less stopped building DIY cabs years ago, although I do currently have a few small projects in my work queue.

Absolutely. It's basically all we DIYers had back in the day, books. I had the Radio Shack one and another by David Weems.

I remember getting a DOS based speaker box calculator in high school (talked the voc school teacher into letting me buy it on the schools dime for "education") and thinking, man this is the future!!

 

[6thplanet]

Since we're talking baffles, shameless plug for my latest build. I'm pretty proud of the baffles on this project.
These will be entered in this year's Parts Express Speaker Design Comp. Judges this year are Vance Dickason, Jerry McNutt (Eminence Speakers), and Andrew Jones.

Always a great time at the event. If you're in the neighborhood, swing by and check it out!

Speaker Design Competition

 

[Jazzdogg]

Agedhorse said: "Because this energy is used (both constructively and destructively), it effectively steals from Peter to pay Paul".

I say if you steal from Peter he is likely to get awfully sore, and we all know it's no fun trying to do business with a sore Peter.

I don't know why, but your post reminded me of a quote I first heard at least five decades ago:
Eros spelled backwards is Sore.