Can I get more bass?

Old Onkyo

Old Onkyo

Audioholic General
For some strange reason, I took the dust covers off the SVS 2000 pros. I was getting excellent base and wanted to see the drivers do their thing. Imagine my surprise when I didn’t see any movement from the drivers!
once I touched one I knew they were firing. Does this mean I am not driving them hard enough? (Poor pun intended)
 
TLS Guy

TLS Guy

Seriously, I have no life.
For some strange reason, I took the dust covers off the SVS 2000 pros. I was getting excellent base and wanted to see the drivers do their thing. Imagine my surprise when I didn’t see any movement from the drivers!
once I touched one I knew they were firing. Does this mean I am not driving them hard enough? (Poor pun intended)
That is a ported sub. That is known as a Helmholtz resonator, and is an acoustic transformer. At the operating frequency of the deep bass, the pressure inside the box is very high, and that limits cone displacement. So the air movement is coming out of the port, which you will see if you put a candle in front of the port.

The whole problem with sealed designs, is that only cone movement displaces air. A loudspeaker cone is a very poor coupler to the air in the room in the lowest frequencies. Pipes and horns are even more efficient.

Take a look at this recent sub design, I did for a member. Take a look at cone displacement with frequency, and the vent air velocity especially.

Also take a look at the impedance curve. The tuning frequency is right at the mid point between the two peaks of impedance, around 22 HZ. Note how in the region of the tuning frequency cone displacement falls, but vent air velocity increases. As you fall below peak port air velocity, cone excursion increases, but sound level drops away at 24 db per octave.
 

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lovinthehd

lovinthehd

Audioholic Jedi
You mean you thought the cone would be moving like you see in some videos of a driver pushed to extremes of cone movement in a competition or something? Why I generally leave my covers in place, ain't much to look at. Even with a sealed sub.
 
Old Onkyo

Old Onkyo

Audioholic General
That is a ported sub. That is known as a Helmholtz resonator, and is an acoustic transformer. At the operating frequency of the deep bass, the pressure inside the box is very high, and that limits cone displacement. So the air movement is coming out of the port, which you will see if you put a candle in front of the port.

The whole problem with sealed designs, is that only cone movement displaces air. A loudspeaker cone is a very poor coupler to the air in the room in the lowest frequencies. Pipes and horns are even more efficient.

Take a look at this recent sub design, I did for a member. Take a look at cone displacement with frequency, and the vent air velocity especially.

Also take a look at the impedance curve. The tuning frequency is right at the mid point between the two peaks of impedance, around 22 HZ. Note how in the region of the tuning frequency cone displacement falls, but vent air velocity increases. As you fall below peak port air velocity, cone excursion increases, but sound level drops away at 24 db per octave.
So… I really don’t want to see the cone moving so much.
I am always looking for a little more!
 
lovinthehd

lovinthehd

Audioholic Jedi
Perhaps...
If you get your kicks watching the structure fall down around you! :D
The driver, man, concentrate on the driver. If using good psychedelics the room vibrations could be quite interesting, tho :)
 
Old Onkyo

Old Onkyo

Audioholic General
Man I just remember when it was real simple.

I would love to press one button, system fires up, without hearing, “there is no picture, there is no sound, the sound doesn’t match the picture. “

Kind if reminds me of my old nova. Great car, when she wanted to run.
 
D

Danzilla31

Audioholic Spartan
Man I just remember when it was real simple.

I would love to press one button, system fires up, without hearing, “there is no picture, there is no sound, the sound doesn’t match the picture. “

Kind if reminds me of my old nova. Great car, when she wanted to run.
So too sum up this thread you don't want your woofer to move

You want your house to move!

Now we're having some fun! :D
 
3db

3db

Audioholic Overlord
For some strange reason, I took the dust covers off the SVS 2000 pros. I was getting excellent base and wanted to see the drivers do their thing. Imagine my surprise when I didn’t see any movement from the drivers!
once I touched one I knew they were firing. Does this mean I am not driving them hard enough? (Poor pun intended)
Play the opening sequence of "Live, Die, and Repeat" if you want to see your driver moving. Dont play it too loud as it will damage your subs.
 
Old Onkyo

Old Onkyo

Audioholic General
3db, I will check it out and report back. You guys are brilliantly funny.
 
highfigh

highfigh

Audioholic Slumlord
Also take a look at the impedance curve. The tuning frequency is right at the mid point between the two peaks of impedance, around 22 HZ. Note how in the region of the tuning frequency cone displacement falls, but vent air velocity increases. As you fall below peak port air velocity, cone excursion increases, but sound level drops away at 24 db per octave.
When did you design this box?
 
TLS Guy

TLS Guy

Seriously, I have no life.
Thanks- looks like a good candidate, although Parts Express doesn't have any.
Digikey have 79 in stock.

I chose that driver in part because he lives in Sweden and therefore has access to Scandinavian drivers. However it does make a very good cost effective sub.

What is it you are looking for in a sub?
 
highfigh

highfigh

Audioholic Slumlord
Digikey have 79 in stock.

I chose that driver in part because he lives in Sweden and therefore has access to Scandinavian drivers. However it does make a very good cost effective sub.

What is it you are looking for in a sub?
Not actually looking, but if something comes along that does a decent job, I'll look at it. I have been a fan of Scandinavian drivers for a long time and if you remember, the speakers I built with the crossover you sent are Peerless and Vifa. Once I retire, I plan to design some speakers that will use ScanSpeak and/or SEAS.
 

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