How to get real 16Hz...

[delahais]

Originally posted by Giskard
I've posted schematics of the BX63 and BX63A numerous times. I've also uploaded the BX63 response for those who use BB6P. I've posted how to remove the low pass filter in the BX63, leaving just the EQ. You should be able to find the threads doing a search for BX-63 or BX63.

If you want to try a fun little LF EQ try this - Eight Band Sub-Woofer Graphic Equaliser

He has other fun projects as well...

The top designers at JBL are not shy about using EQ. The latest crop of transducers such as the ME150HS, 1500AL, 1400ND, 1500FE, 2242H, etc. respond quite well to some LF and VLF EQ.

hi GISKARD,
thank you, interesting !
regards.

[pdemondo]

I have a couple of Phoenix Gold Cyclones each in
a 6 cubic ft. (net) enclosure (cubes) firing down. There is
1 15 in Stryke audio passive radiator on each side
box tuned to 16 hz. (2 PR per box).

I can rattle my foundation and communicate with
whales. for 30hz and up about 10 Watts is fairly
loud. I max out the PRS at 15 hz , I am adding
2 more and tuning to the same freq.

Most of the time the addition to the mains is very
subtle. My subs only put out from 50 hz on down.
(Using active crossover).

I couldn't afford the contrabass so I went this route.

[Niklas Nord]

Then, to get rid of boominess, there should be interesting to
try selaed boxes?

[pdemondo]

Well boominess is not really a problem.
(I could just be a bass nut)
I started out with sealed boxes but I could
reach their limit with Jurassic Park III. I figured
I would add PRs tuned low (turned out to
be 16hz) to take the low end work away
from the cyclone.

Also, I didn't think the subs were sensitive enough
on the bottom end.


I am powering the subs with a Pioneer Spec 1
amp. Its output starts to drop below 20hz.
I also use the Spec 2 preamp for volume
adjustment of the sub. I feed the subs with
a DOD electronic crossover set to about 50hz.

My house is open so the sound plays into about
2000 or so sq. ft of my house.

With the PRs I get noticeable 35 hz - down reinforcement.

Since I have tuned so low, I can't notice delay from subs
vs. mains (250Tis). It sounds tight.

More than anything, with the PRs, I really notice impact
on music much more that doesn't seem to be coming
from the subs. When you turn the subs off the
impact diminishes. (Impact less "full-bodied")
(MY AB comparisons).

The 1812 Cannon fire sounds real. Thunder is
quite enjoyable as well.

I kept the holes I cut out (used a thin router bit) just in
case I decided to reverse course, but I was surprised
I think it works well.

The cyclones seem to be just right for the 250Ti's, they help
in the 30hz on down range.

The hardest part is there are no T/S parameters to deal with.
I have been using trial and error for about a year or so and
I think I am almost there.

I have cut and rounded solid teak edges and have started
applying the teak veneer. The "look" like the TI's in grain.
the tone of my veneer is more brown, the Tis are a little
more towards red. When they finally look like furniture,
I can post some pics.

[Niklas Nord]

Sound great.

[Ralf]

I play arround with some considerations. Has anybody build a Compound-Box with 2245H?

Ok. the pressure goes down, but the kick in the near of 20Hz is interesting...(theoretical software results)

[4313B]

That I haven't tried...

[Ralf]

Originally posted by Giskard
That I haven't tried...

Is there any reason why not?

[4313B]

I never had the need.

What is the "real estate" cost we are talking about here?

[Ralf]

Originally posted by Giskard
I never had the need.

What is the "real estate" cost we are talking about here?

Ok. the discussion about optimized acustic rooms and their costs is maybe a theme for a new thread...

Look at my rough draft. What is if the chassis and the vents are not on axis? Is their any problem?

[Ralf]

...and here the theoretical frequencies:

[Niklas Nord]

Tim G:
"Using Unibox, with a pair of 2245H in sealed boxes with at least 4.8 cu ft per driver, I get 104.5 dB at 16Hz at 1M, before room gain, at xmax. If you your room has rigid walls and you place the drivers together in a corner I would expect at least 112dB at 16Hz.

With 4 drivers you are looking at 110.6dB anechoic at 16Hz. THis would give you close to 120dB with room gain. You would be hitting 120dB anechoic at 27.8Hz.

These models do not account for driver compression and it does not tell me how much power it takes to hit xmax."



Can this really be true, can the 2245 really reach souch
high output in a sealed enclousure? IF thats so, then i
vill absolutely try selaed..

[Ralf]

To get really 16 Hz it is a Problem with Power compression....so I downgrade to 20Hz...but this is possible with enough sound pressure...my computations resulted in the following:

- Together with my system (2x4530/2226H + 2x2206, 2x2344/2426J, 2x2404) 20Hz can be only reached, if 4 2245H-18"-Speakers are used (cutoff 50-60Hz).

The following conditions are to be considered:

- maximum sound pressure adapted to the 4530

- maximally linear frequency characteristic down to 20Hz

Here is the solution:

4 x vented enclousures
(housing with the following dimensions (25mm MDF):

Width x Depth x Height
573mm x 673mm x 1036mm

3 Ducts:
outside dia. meters of 100mm,
inside 93,7mm,
length 314mm

Pictures will follow...

Greetings
Ralf

[Ralf]

I purchased today the third 2245H chassis.

Soon is it so far...

[mikebake]

Ralf rocks!!