Featured Facts or Fiction

[RobGMN Premium Member]

More excursion does not mean you will have more bass. Excursion is desired if you want to feel the bass.

If you have two 6" woofers moving at a rate of 60Hz, with one moving 4" per cycle and the other moving 6" per cycle, will they both sound the same? Will they both pressurize the air the same?

I'm harkening back to a wave tank I saw. You could adjust frequency and stroke of the piston that drove the "wave bar". Leaving the frequency the same but changing the stroke mad a very big difference in the wave produced. Liquid dynamics.

I don't know the translation into SPL, though. I would think more excursion at the same frequency = more SPL.

 

[Jimi77 Premium Member]

If you have two 6" woofers moving at a rate of 60Hz, with one moving 4" per cycle and the other moving 6" per cycle, will they both sound the same? Will they both pressurize the air the same?

I'm harkening back to a wave tank I saw. You could adjust frequency and stroke of the piston that drove the "wave bar". Leaving the frequency the same but changing the stroke mad a very big difference in the wave produced. Liquid dynamics.

I don't know the translation into SPL, though. I would think more excursion at the same frequency = more SPL.

More excursion at the same frequency should = more spl unless we're talking ported designs.

 

[RobGMN Premium Member]

True... I have often wondered at what size and mechanical limits does a subwoofer become too slow to keep up with music?

I think it's an issue of how much can you afford to spend on driving it. There's a video of a guy who made a "subwoofer" that literally caused doors in his house to open and close with the pressure changes. It used a fan with variable-pitch blades.

Finding those mechanical limits is something a billionaire should do, just to give audio people something to marvel at.

 

[ThxOne Premium Member]

I think it's an issue of how much can you afford to spend on driving it. There's a video of a guy who made a "subwoofer" that literally caused doors in his house to open and close with the pressure changes. It used a fan with variable-pitch blades.

Finding those mechanical limits is something a billionaire should do, just to give audio people something to marvel at.

I agree... that amplifier would have to be a massive piece of engineering to be able keep such a huge coil under control in the magnetic gap. Still, at some point the weight of the cone would have to create so much inertia that it would overcome the magnetic pull.

 

[Old_Slapper]

If you have two 6" woofers moving at a rate of 60Hz, with one moving 4" per cycle and the other moving 6" per cycle, will they both sound the same? Will they both pressurize the air the same?

I'm harkening back to a wave tank I saw. You could adjust frequency and stroke of the piston that drove the "wave bar". Leaving the frequency the same but changing the stroke mad a very big difference in the wave produced. Liquid dynamics.

I don't know the translation into SPL, though. I would think more excursion at the same frequency = more SPL.

Excursion will give you a higher pressure level that you feel, such as blowing your hair around when the bass hits. But more excursion doesn't necessarily mean more bass. A perfect example is pro audio speakers. Most of them will have an excursion of no more than 10mm. It's because feeling the pressure isn't the goal. It's feeling the beat. Now, if you add excursion to the same speaker, you might get more bass, but it is quite possible for the speaker with less excursion to produce more bass?

 

[ThxOne Premium Member]

Excursion will give you a higher pressure level that you feel, such as blowing your hair around when the bass hits. But more excursion doesn't necessarily mean more bass. A perfect example is pro audio speakers. Most of them will have an excursion of no more than 10mm. It's because feeling the pressure isn't the goal. It's feeling the beat. Now, if you add excursion to the same speaker, you might get more bass, but it is quite possible for the speaker with less excursion to produce more bass?

True, look at those giant PA system subwoofers. 20+ inches and hardly any excursion. TONS of bottom end.

 

[Old_Slapper]

True, look at those giant PA system subwoofers. 20+ inches and hardly any excursion. TONS of bottom end.

Yes! I used to design sound systems for clubs, and I was blown away to see they had an excursion of about 7mm. However, they will shack the room and rattle windows.

 

[RobGMN Premium Member]

Excursion will give you a higher pressure level that you feel, such as blowing your hair around when the bass hits. But more excursion doesn't necessarily mean more bass. A perfect example is pro audio speakers. Most of them will have an excursion of no more than 10mm. It's because feeling the pressure isn't the goal. It's feeling the beat. Now, if you add excursion to the same speaker, you might get more bass, but it is quite possible for the speaker with less excursion to produce more bass?

Is that where the split into SPL woofers versus high-excursion woofers comes into play?

Was the Mitsubish Diatone real, or internet mythology?

 

[ThxOne Premium Member]

Is that where the split into SPL woofers versus high-excursion woofers comes into play?

Was the Mitsubish Diatone real, or internet mythology?

Real I believe. A 1.6M speaker. Can you imagine???

 

[RobGMN Premium Member]

Real I believe. A 1.6M speaker. Can you imagine???

Would be nice in a movie theater. Until the screen fell down.

 

[Jimi77 Premium Member]

Excursion will give you a higher pressure level that you feel, such as blowing your hair around when the bass hits. But more excursion doesn't necessarily mean more bass. A perfect example is pro audio speakers. Most of them will have an excursion of no more than 10mm. It's because feeling the pressure isn't the goal. It's feeling the beat. Now, if you add excursion to the same speaker, you might get more bass, but it is quite possible for the speaker with less excursion to produce more bass?

They're ported or horn loaded, so they rely on power handling more than excursion.

 

[Old_Slapper]

Is that where the split into SPL woofers versus high-excursion woofers comes into play?

Was the Mitsubish Diatone real, or internet mythology?

I would say yes. If excursion provided the highest SPL, everyone would be running RE Audio XXX subs for SPL competitions. They have a 61mm one-way motion of travel. However, there are subs with half the excursion winning these competitions. It has to do with the leading subs handling over 5000w while the RE Audio XXX is only 2000w.

As for the Diatone, I laughed when I read that. I was just reading about that subwoofer yesterday. Apparently, it's real and they were made to order.

Diatone D-160 Specifications Diatone

 

[ThxOne Premium Member]

Think of the oscillation in an SUV with a bunch of those XXX's!!! Wouldn't the up and down motion eventually get the car to "hop" with the subs?

 

[Old_Slapper]

I have never felt cabin pressure as much as 2 of those in a Tahoe, except for an SPL competition vehicle.

 

[ThxOne Premium Member]

Did anyone else ever get to see the Kicker van in the 1990's? It was an Astro Van with 4 Kicker 18's in the back. I wish I could remember the actual year. I saw a demo of the van where they back it into a concrete pillar, not a huge pillar but they were able to crack the pillar with the bass. It was impressive.