Bass is lacking.

[michael hurd]

Ok, let us get back to the basics. A vent will resonate at a particular frequency, this is dependant on: surface area of the port ( diameter ), length of the port and the physical internal volume of the enclosure.

We can say that the volume of the enclosure is somewhere between 8.6 - 8.8 cubic feet based on your description.

A 3" diameter vent is simply too small for a 15" diameter woofer. I suggest cutting the cabinet and fitting yourself a 6" diamter port.

When we come up with a better candidate for a 15" diameter woofer ( for instance the JBL 2226 ), the tuning is dependant on the parameters of the woofer called the Thiele-Small paramaters. To tune your existing boxes to 35 hz with a 6" diameter port, you need a length of about 2.65" long. ( I say about because we cannot accurately measure the volume of your enclosure right now. )

I would recommend starting with a port about 3" long, and try it. Shortening the port will raise the tuning frequency. You can cut off small amounts at a time.

[TBrennan]

"Do the JBL 2226 Speakers have a lot of punch? Can you feel them?"

Yes to both questions. I used to use 4 of them in my hi-fi. Lots of my pals used them too.

Listen to Michael too though. If he thinks that Eminence will work it probably will, maybe better. Eminence makes some good sounding stuff that's cheaper than JBL. Not as cool though. ;-)

[Iknownothing16]

When we come up with a better candidate for a 15" diameter woofer ( for instance the JBL 2226 ), the tuning is dependant on the parameters of the woofer called the Thiele-Small paramaters. To tune your existing boxes to 35 hz with a 6" diameter port, you need a length of about 2.65" long. ( I say about because we cannot accurately measure the volume of your enclosure right now. )

I would recommend starting with a port about 3" long, and try it. Shortening the port will raise the tuning frequency. You can cut off small amounts at a time.

Umm... what is the 2.65" long part measuring? The length of?

[michael hurd]

Iknownothing16: Sorry if I am talking over your head, trying to explain it as well as I can. If you were to change to say a JBL 2226 woofer instead of what you have, you would want to "tune" the enclosure to work with that woofer and box. You can't just drop something in and expect it to work properly.

The electrovice woofers you have are great products, just not for the application. The optimum enclosure is smaller than what you have and they will not go low based on the parameters. Also, who knows what your current enclosure is tuned to, if it is a circular port and we have the length ( you gave us the diameter as being 3" ), we can calculate the approximate resonant frequency.

To recap: the woofers you have are great, just not for your application, the port ( also called "vent" ) is too small ( will be noisy at modest drive levels and compress at higher ones )

A JBL 2226 will work better for you, and also enlarging the current diameter of the port to 6" ( based on Vance Dickason's recommendations )

To use a 6" diameter port and "tune" the enclosure to 35 hz ( models good ) the port must measure about 2.65" long.

Does this help?

[michael hurd]

To build a basic rectangular 16 cubic foot box with 2 18" dirvers and 2 ports is pretty simple. I will say that this is the easiest way to get loud low bass, for the intended usage. Hang the 130 wpc amp on your main speakers and the 250 wpc amp on the Sigma-Pro's.

The simulation shows 122 db @ 1m at 35 hz, 124 db @ 38 hz, 128 db @ 48 hz. This is some serious output for $ 155 woofers. Total build cost - under $ 500 for sure, you already have an amp to use, just need a crossover, maybe the Harrison labs F-Mod inline crossovers.

[Iknownothing16]

So the port measures 6" inches in diameter and when you say 2.65" long you mean like the depth? I'm just not getting that part. Also should I get the JBL with 8 Ohms or 4? The previous woofers were both 8 Ohms (The speakerlab and the Electrovoice). If you could somehow convey a picture of what you mean with the 2.65" long thing that'd be great, and if not that's ok to. Thanks for all the help so far.

[Iknownothing16]

Also does anybody else have any recommendations for other woofers that would work well with the cabinet? Needs to be able to take a lot of power and produce a lot of volume. Must be under $380 or so. Also needs to be efficient, preferably a little more so or equal to the EVX-155.

[Iknownothing16]

Hey sorry to keep bothering people but can anybody finish explaining to me what the 2.65" means? Also what's the difference between the 8 Ohms and the 4 Ohms? Thanks for all the help so far.

[Jay481985]

Nice to see you back Michael Hurd

[fastlane]

I have 2 JBL 2035HPL 15" woofers I picked up locally that might work for your application. I know they were part of a JBL pro cinema speaker system. Here is a link. http://www.jblpro.com/pages/pub/cinema/4675c.pdf i doubt I will everuse them as I had intended. let me know if you're interested.

Jon Fleming

jcflemn@yahoo.com

[mas]

Hey sorry to keep bothering people but can anybody finish explaining to me what the 2.65" means?

The 6 inch diameter port would be 2.65 inches in length.

[WMcD]

I'll let other folks advise you on the selection of specific bass drivers and ports.

- - - - - -

Ports, though, are the box or cylinder (open on two ends) which extends from the exterior of the box to the interior. This traps a mass of air which is driven back and forth within the port.

The front of the woofer diaphragm radiates, very, very approximately, from 70 Hz up to 1000 Hz. Down below 70 the back of the woofer is activating the spring of the air trapped in the box and the mass of air in the port. From about 70 Hz to 30 Hz the majority of the sound is coming out the port.

Getting all this to work properly depends very much on matching the parameters of the driver to the box size and the port dimensions.

In the early days before this "tuning" was well understood, people would just make a hole in the plywood box and experiment. So the term was "port" like a porthole and was just as deep as the plywood with a hole. Later it was understood that the system worked better if the port was more like a deeper box or tube.

- - - -

I suspect the original box and port was set up for the SpeakerLab driver. The EV needs some box size and port size to work well, and the original box is not correct. So you must alter the box and port to fit the EV or find a driver which matches the box and port. Actually, I expect you'll have to find some driver which fits the box size and then make some modifications to the port, which is not too difficult.

- - -

You ask about the horn. I'll make a guess.

It may well be one of SpeakerLab near copies of the Klipsch K-400. SpeakerLab made a metal version and a fiberglass version. The big end is the "mouth". If so, the mouth (open to the atmosphere) should measure about 5.7 inches high by 17.5 inches wide. The horn should be about 22 inches long. The driver spins onto the the small end (throat). It could be that you have an Atlas driver which was relabeled as a SpeakerLab.

= = =

Gil

[DrWho]

For what it's worth, you can easily drive a single 2226H to 120dB in
a ~4cubic foot box tuned to 40Hz or so (measured in half space). Their
Xmax is their rated linear behavior - the mechanical can handle 22mm
one way. When you're really pushing it, you run into issues with the
spider slapping against the top of the magnet assembly. If you go a bit
further, you'll slap the VC against the rear plate, but it usually
doesn't break it because the VC isn't wound all the way down as there's
about a 1/4" of cardboard to absorb the shock. You'll just have a lot
of grinding sounds to deal with. Usually what breaks is the VC wiggles
as the driver comes out and wedges itself on top of the magnet, tearing
the spider and pushing it through diaphragm. They were nearly
impossible to melt. Crank up a pair of these drivers and they'll knock
you over. [] 4 of these drivers can be flat to 40Hz and do 136dB with
moderate levels of distortion (gotta use a highpass).

Anyways...

To
answer one of your questions - no, there is probably nothing in the
crossover that will reduce the low frequency extension. It's rare to
build a passive high pass below 200Hz or so since the components have
to be huge. As mentioned, it's probably a driver/cabinet misalignment.

Attached
is the predicted performance for your driver in your cabinet based on
the numbers Gil and Mike posted, and then a prediction for how you can
easily improve your current cabinet. Blue is your cabinet with an
effective 30Hz tuning in your cabinet - but the size of the port is
going to lend it to being lossy and more reduced in the low end
(probably 10dB down at 30Hz instead of 6dB). Green is what would happen
if you cut another 3" hole in your cabinet: a ~40Hz tuning, but it's
still going to be a bit lossy. You could move to two 4" diameter ports,
each 2" long with much much better results. A pair of these cut down to
2" should work well and not be too expensive:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=260-403

<EDIT>

Just to be clear, cutting another 3" hole will have the same frequency plot show in the graph as two 4" diameter ports that are 2" long.

[michael hurd]

For my money, I would probably substitute the Usher 15" PA at parts express, it is not as overdamped as the EV, power handling is decent, but you do lose a little x-max to both the EV and the JBL 2226. The parameters are better for the box you currently have though. I would put the difference that you get back from the EV drivers to buy 2 of the Eminence Sigma-Pro 18".

[butters]

you say a 6 inch port 2.65 inches long, for a vent,  this can't be right. every other info I've read says 7 or 7.5". long for the vent.  who actually knows to tune a 2226h down to 30 Hz

[butters]

my cabinet has a 2226h JBl with a 5 inch round port and its long from the factory. Will installing a 6 inch port make it go lower to 30Hz and adding better dampning instead of polyfill. Polyfill isn't much. I'm an upholsterer and I'm going to use cotton batting we use in furniture. I've read use 2 layers on the back and only cover one side of each wall, the guy said he tried everything and this sounded the best.