Are the ports to big

[Integrexman]

I made these cabinets in 1990. The driver is a E140. I don't remember how I calculated the port area when I made them. The internal dimenstions are 22.5 wide, 23.625 high, 15.5 deep. That equals 4.77cu.ft.

I think I made the ports to big they are very efficient but have a hard time getting low end out of them. I know 40-50 is about the lowest the E140 would go but I have to EQ 63-100 up more than I think I should. Can anyone tell me what the area of the port should be with this cabinet/driver combination and how low I can expect to go.

Thanks, Keith
http://integrexmachinist.com/videos/All.JPG

http://integrexmachinist.com/videos/E140.JPG

[duaneage]

I think your box is too big for the E140. Your trying to get bass froma speaker not known for bass in a vented box. It's a great speaker but not the best for this application.

The ports look to be 2 x 3 inches, that would be 52 hz in that box give or take a little. Your looking at serious delay in the range your trying to get bass out of the driver. I would suggest using a bass driver, something that works in 4-5 cu ft and has the right type of suspension for the job.
http://img.photobucket.com/albums/v732/duaneage/e140-2.jpg

http://img.photobucket.com/albums/v732/duaneage/e140-1.jpg

[Integrexman]

Sorry I forgot, the ports are just a little over 4" in Diameter. The baffle is 13 ply birch so around 11/16" thick.

[duaneage]

They are really tuned in that box to 62 hz. Try plugging them both for starters.

For a vented alignment the best result is .65 cu ft , 4 inch vent (only 1) 6 inches long and that is tuned to 77Hz.

Your not going to get knee bending bass from this driver, it's just not there.

Try and fill the volume up inside the cabinet, plug one vent, and use 6 inches of PVC, see what happens. Books, magazines, blocks of wood, anything solid and non compressible

Good luck.

[duaneage]

Here are few alignment suggestions. Yours is in blue. Red and yellow are probably your best bets, since they produce the best group delays and protect the driver from excursions.

Big boxes can be expensive, but the E140 can take it. I think that driver is more of a horn loaded system beast IIRC.
http://img.photobucket.com/albums/v732/duaneage/e140-3.jpg

[duaneage]

And by expensive I mean for recone kits. This group delay graph gives an idea of what a driver in a big box is doing when it hits the port resonance. While not exactly excursion results, you can see a marked difference compared to more optimum alignments. Some drivers are meant as really good midrange drivers (read guitar speakers) while others do duty as bass drivers. The suspension on your driver is probably tight as hell, not really very compliant. A bass driver will be very loose, it depends more on the box for support.

http://img.photobucket.com/albums/v732/duaneage/e140-4.jpg

[duaneage]

I played around a bit and got a better curve from 1 cu ft at 77 hz. Go 7 5/8" on the 4 inch vent and see how it goes. You'll get usable bass to 90Hz, maybe a little down to 80Hz

http://img.photobucket.com/albums/v732/duaneage/e140-5.jpg

[Zilch]

JBL used that driver in Cabaret Series boxes about the size of yours tuned to 40 Hz.

Go to the hardware store and get a pair of 4" plumbers' test plugs to block one of the ports in each of your cabinets. That'll tune them to ~39 Hz and you should hear much improved bass response. You're presently tuned to ~52 Hz.

If you like that result, then because your vent velocities will get high at high SPL, you'll want to keep the two ports in each box open instead by adding ducts, 2 x 4" @ 4.57" or 2 x 3" @ 1.61". I offer the 3" option because it may be easier to just make those on plywood squares and install them in your existing openings from the inside.

BB6P suggests tuning even lower, 34 Hz, using duct lengths of 8.15" or 3.54" for 4" or 3" diameters, respectively. Group delay is highest in this alignment, but peaking at 16 ms at 34 Hz, it's still within acceptable limits.

E140's not an extended bass woofer. That's about the best bass you'll get out of them in those boxes, but it's certainly better than what you are presently getting.

Check my calcs, please.... :yes:

[scott fitlin]

Also, I have the old E Series brochure, which includes a selection of cabinet internal volumes, and port tunings for various frequencies. Tomorrow, I'll scan them and post it, and maybe it can offer some usable info, as well.

As Zilch said, your never going to get extended bass from them, as they are rated to 40Hz. But, I know that woofer well, and you can get good sounding bass from them, and with a sub, could actually get sound you really dig.

[SMKSoundPro]

Why not use a 2235 or E-145?

His 2344 and 2405 atop looks great!

So close to a L300.

Try a 2235 or 2234, or 136, 2225.(maybe)

[grumpy]

Keith, what are you trying to use these for? Home use?

If you're mostly happy, check specs on JBL 4507 box
(5ft3, 40Hz) w/ 2225 and don't expect miracles.

[Integrexman]

Thanks for all the comments.

I use them at home and for DJing now and then. I am thinking about building new cabinets this summer and will probably use a different driver. With this cabinet/driver I am trying to see if I can get a little flatter response at the bottom end. My RTA and EQ are telling me I am rolling off at about 125Hz or higher, I would like to try and get it flat down to at least 50-60 by making new ports. I know I will never get down below 40 with an E140.

[SMKSoundPro]

WHUP!

There you said it!


"and for DJing now and then"

Now let's talk about making some serious bottom end!

Dump the 140.

[Integrexman]

Thanks for all the help. I think I am going to start by making vents 3"X1.7" and I can make them shorter if I need to. The blue lines is what I have now.
http://integrexmachinist.com/videos/E140box.gif

http://integrexmachinist.com/videos/E140vents.gif

[duaneage]

There is an old saying between engine builders,

Don't try to make a race horse out of a mule.

First you must start with a driver designed for the application, then optimize it. I would ebay the E140 drivers, you should get good coin for them, and apply it to an appropriate driver.

[Integrexman]

I made the new ports today. I made the ports a little long to start with (I can always make them shorter) and so I didn't have to remove the speaker I decided to mount the ports from the front.

Step 1. Glue 3 Peaces of birch together bore a 1" hole through so I could turn the O.D. round.
http://integrexmachinist.com/E140/Arbore.JPG


Step 2. Turn the O.D.
http://integrexmachinist.com/E140/Turning.JPG
http://integrexmachinist.com/E140/Turned.JPG

Step 3. Bore port to size.http://integrexmachinist.com/E140/Boreport.JPG

I just mounted them tonight and sound good so far. They are 3" Diameter, 2.1" long. I will do some testing next week and post the results. I also made videos of the ports being made I will post a link soon.
http://integrexmachinist.com/E140/PortInstalled.JPG

[Integrexman]

I was wondering, is taking the ports from 4" to 3" will it have much affect on the overall efficiency. Just listening I can hear an improvement the low end.

Here is the link to the videos.
http://integrexmachinist.com/E140/PortSize.mpg
http://integrexmachinist.com/E140/BorePort.mpg

[macaroonie]

You seem to have some nice tooling to hand ...:applaud:

[duaneage]

The driver determines the efficiency, the ports determine the loading and tuning of the box. Smaller ports can be shorter, and easier to fit, but can exhibit power compression at high levels. The driver can become unloaded at high volumes, the ports can whistle as well. As a rule you should try to fit as much port area as you can into a box if you intend to run it at high levels. Obviously there are limits, but you need the right volume and the right tuning frequency. Once that is found, the largest port area you can fit.

I would look into the telescopic ports partsexpress sells. They would allow you to quickly change the port length for testing and then make permament ports from the results/