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View Full Version : Better Bass is on the Way!



toddalin
11-10-2005, 04:12 PM
Purchased the K140 basket on ebay to complete my system. I previously bought three 2205 baskets (LCR) and the K140 will serve as the new sub. All will be reconed as 2235s. These are to replace the four 130As.

Next step is to get them all in to OCS for recone and maybe recharge. Anyone want to float a loan???:o:

bigyank
11-10-2005, 04:55 PM
:useless: Bring em on!


Yank

toddalin
11-10-2005, 05:00 PM
:useless: Bring em on!


Yank

OK, they go here and here:

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/speaker2.jpg


And here and here.

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/speaker4.jpg

JuniorJBL
11-10-2005, 06:32 PM
OK, they go here and here:
And here and here.



Well Done:applaud:

Tom Loizeaux
11-11-2005, 06:06 AM
Toddalin,
Why did you put a bullet tweeter in your sub cabinet?

Tom

Don C
11-11-2005, 07:54 AM
Toddalin,
Why did you put a bullet tweeter in your sub cabinet?

Tom
I think that's a full range system.

JuniorJBL
11-11-2005, 07:59 AM
A center channel. It is under the screen! :applaud:

toddalin
11-11-2005, 09:46 AM
A center channel. It is under the screen! :applaud:

Exactly. The cabinet holds a 15"/LE175-HL89/075 for the center channel (to match the L/R) and a second 15" for use as one of two subwoofers. The face slants back to better aim the speakers to the seating area.

The cabinet has three chambers. The outter chambers that hold the woofers are each 4 cu ft tuned to 34 Hz and the center chamber is 2 cu ft tuned to about 60 Hz. The design smooths out the impedience curve creating two smaller peaks. I have a switch on teh cabinet that also allows me to use the two woofers in parallel on the subwoofer amp when the center channel is not used (such as listening to music). When both 130As were craking in unison, the bass response really improved... probably about 6 dB. Part of this would be due to the reduced impedience on teh amp (8 ohms as opposed to 16), but the cabinet definitely "come alive" too.

The bass is supplemented with a 2,700 watt Sunfire Signiature True Subwoofer (which was a necessity with the 130A). Hopefully the 2235 will take some work off the Sunfire and let me reduce its crossover point.

spkrman57
11-11-2005, 10:13 AM
If it sounds as good as it looks, can't go wrong!

Ron:applaud:

Zilch
11-11-2005, 10:24 AM
The cabinet has three chambers. The outter chambers that hold the woofers are each 4 cu ft tuned to 34 Hz and the center chamber is 2 cu ft tuned to about 60 Hz. The design smooths out the impedience curve creating two smaller peaks.TCB kinda?

http://audioheritage.org/vbulletin/showthread.php?t=6289

toddalin
11-11-2005, 10:50 AM
TCB kinda?

http://audioheritage.org/vbulletin/showthread.php?t=6289

Yes, exactly! Except that my woofers are in the two outter chambers. The inner chamber houses the horn/tweeter/crossovers and with the exception of the top and bottom, which are different sizes due to the slant-back, there are no interior parallel walls in the cabinet.

edgewound
11-11-2005, 11:20 AM
Yes, exactly! Except that my woofers are in the two outter chambers. The inner chamber houses the horn/tweeter/crossovers and with the exception of the top and bottom, which are different sizes due to the slant-back, there are no interior parallel walls in the cabinet.

I don't understand...why is the center chamber tuned if there is no woofer in it?

Other than that, looks like you've got a killer home theater/music system.

Tom Loizeaux
11-11-2005, 12:40 PM
I think that's a full range system.

Ahh, I didn't see the "potato masher" horn in the other photo!

I bet they sound great!

Tom

toddalin
11-11-2005, 02:03 PM
I don't understand...why is the center chamber tuned if there is no woofer in it?

Other than that, looks like you've got a killer home theater/music system.

When I went to design the cabinet, I wanted both speakers to share space, but reduce interaction of the center channel and sub. Recognize that the sub and center are both mono anyway so reproduce much of the same information. I then went to the library to pick up books on speaker design and came across an article on designing a dual-chambered cabinet and it occured to me that I could incorporate this design into my cabinet. I didn't want to split the cabinet into two in the middle as that would have reated problems mounting the other components.

I just did some looking on the 'net and came up with this portion of a thread on the DIY forum and this is the publication I saw at the library:

BAM, I'm not sure which way you are going by the term 'dual Chambered'? I think, since you are talking about using two drivers that you are referring to a seperate chamber for each driver. If that is what you mean, then there won't be any difference, except the difference in the ohm rating of the system. There is another type of dual chambered enclosure, and that is where one driver uses two different chambers that are each vented. I have made this project almost 10 years ago using a Peerless 1056 8" driver, which has been replaced by the manufactorer. David B Weems published this project in Speaker Builder, during the late 80's and was later put in his 1990 book, entitled "Great Sound Stereo Speaker Manual". This book in most likely in your local Public Library. Don't confuse this with his other book,"Designing, building, and Testing Your Own speaker System". I have both, and the first one is by far the better. The article in the book does not go into the theory like the one in Speaker Builder, but I will try to pull it up from memory. Once the Ideal box size and the diameter and length of the port is calculated, the second chamber is 1/2 that of the other. The port leading into the second chamber and leading out of the second chamber is the same as in the first chamber. This will cause the Fb of the second chamber to be 1/2 octave lower than the first. I have not been able to measure this, but if you put your ear to each port, one is able to tell that the port from the second chamber is indeed lower than the first. I hope that this helps you. If you have any other questions, let me know. John L

edgewound
11-11-2005, 02:57 PM
Ahhh....I think I follow you now. The 2 outside chambers are internally ported into the center chamber which in turn, is ported to the front baffle. This would create a primary load at 60hz on the two drivers, but I'm curious how that interacts with the secondary loading at 34Hz. I believe KEF and Mirage both use different size ports in their systems, but that is with a common chamber. Interesting.

Looks like here is the link you used (thanks, Google):

http://www.diysubwoofers.org/prt/dual_chamber.htm

toddalin
11-11-2005, 05:18 PM
Ahhh....I think I follow you now. The 2 outside chambers are internally ported into the center chamber which in turn, is ported to the front baffle. This would create a primary load at 60hz on the two drivers, but I'm curious how that interacts with the secondary loading at 34Hz. I believe KEF and Mirage both use different size ports in their systems, but that is with a common chamber. Interesting.

Looks like here is the link you used (thanks, Google):

http://www.diysubwoofers.org/prt/dual_chamber.htm

I didn't use the link, I used the noted book, but yeah, that's the concept alright. When I figured tuning, I used both ports (into the center box and to the outside) in calculation of the resonant freq. I think they are only considering the outside ports so it would be lower doing it the way in the link.

My volumes are 4 cu ft, 2 cu feet, and the ports are 4" diameter and 9.5" long