TL using Dayton 295-310

[planet10]

What does the polar radiation of a TL/MLTL/QWTL sub most closely resemble? How about when you have a push-push system like you drew?

In subwoofer territory, regardlass of box, or 1 or 2 drivers, the radiation is onmidirectional.

dave

 

[JoshK]

That is true only if it is a true sub correct? If they are built to xo at 100+ then does the same hold true? I guess I am trying to figure out which method I want to persue for my room.

 

[planet10]

That is true only if it is a true sub correct? If they are built to xo at 100+ then does the same hold true?

It is an effect that is related to the size of the box... at 100 Hz the box would need to be on the order of 40" wide or smaller to be omnidirectional.

dave

 

[BassAwdyO]

the bass only is omnidirectional at low frequencys. The higher you cross, the more directional. I wouldnt want to go any higher than 100hz unless you have stereo subs that go next to the mains.

 

[JoshK]

thanks for the response. I realize the issue with above 100hz localization and planned to take that into account.

I guess the key point here is in different usages, woofer vs. sub. I was confusing the two. Wonder if my wife will let me get away with a 20' TL sub in the living room. 😀

 

[RJ]

"I did a dual driver extended max flat alignment ML-TL (forget getting any useful output to 25-30Hz from a TL with this driver):

Quote from original post.

I just finished two prototype TL enclosures with the Dayton 8" Classics.
Here are the results taken with Bass Mekanic & a Radio Shack DB Meter 8 feet away from the speakers. (No adjustments were used on the RatShack meter).
Left TL;
80-70 - 95 db
70-60 - 95 db
60-50 - 95 db
50-40 - 93 db - 87 db
40-30 - 85 db - 80 db
30-20 - 82 db - 71 db
Right TL:
80-70 - 91 db
70-60 - 92 db
60-50 - 93 db
50-40 - 93 db - 90 db
40-30 - 87 db - 82 db
30-20 - 82 db - 72 db

The left TL was medium stuffed.
The right TL was heavily stuffed.
A pic of the heavily stuffed TL;
http://img.photobucket.com/albums/v641/rjakubin/StuffedTL-1.jpg
The medium stuffed TL doesn't have the third leg filled with fiberglass, only two layers of poly.
http://img.photobucket.com/albums/v641/rjakubin/Front_TL.jpg

It was funny to watch Bass Mekanik do it's thing and watch the poly flap in the port.
How did it sound???
I was stunned!!! The clarity just shot out of the speakers.
I couldn't believe the Classic 8's being so cheap could sound so good.
The bass player on Tommy Bolin's album was especially illuminating.
You could actually hear the bass guitar strings vibrate across the pickups. Not only that but you could feel the vibes also!!!!

TL's have won me over that's for sure.
A lot more testing needs to be done before I pick the best sounding speaker. Varying the port size and adjusting the stuffing.

 

[planet10]

Here is the pictoral version of those numbers (note: Excel is a really bad graphing program)

dave

 

[bwbass]

Correction Values for Radio Shack SPL Meter

10hz........+20db
12.5hz.....+16.5db
16hz........+11.5db
20hz........+7.5db
25hz........+5db
31.5hz.....+3db
40hz........+2.5db
50hz........+1.5db
63hz........+1.5db
80hz........+1.5db

🙂

 

[planet10]

Correction Values for Radio Shack SPL Meter

I've seen a couple of those before... my worry has always been how big the sample set of devices was (ie is this applicable to my meter or only the one measured)

Anyway here is a before & after adjustment for the meter deviation as given

dave

 

[RJ]

Thanks bwbass for the correction figures and planet10 for the graphs.
I've been enjoying the heck out of them speakers. Throwing a lot of different genres of music on them and they all sound really good.
I've got to thank Martin King, GM and cjd for all of their help.

 

[planet10]

I've been enjoying the heck out of them speakers.

🙂

 

[GuyPanico]

RJ: This thread has just gotten me even more excited about my own TL sub project. 🙂 Although mine a less ambitious, straight open ended TL.

 

[RJ]

The reason I folded mine was so I could mount my MTM's on top and still have the tweeter about ear level. Mine came out to 32 1/2" high.
Good Luck on yours GuyPanico.

 

[bhg41088]

The reason I folded mine was so I could mount my MTM's on top and still have the tweeter about ear level. Mine came out to 32 1/2" high.
Good Luck on yours GuyPanico.

Can you post demensions for your TL, RJ?

 

[RJ]

I made two versions. One with a 9" baffle and the other with an 11" baffle;
http://img.photobucket.com/albums/v641/rjakubin/TLsGuts-1a.jpg
http://img.photobucket.com/albums/v641/rjakubin/StuffedTL-1.jpg

Here are the frequency graphs. One fully stuffed (blue) and the other partially stuffed (red);
http://img.photobucket.com/albums/v641/rjakubin/T-Line-MJKResponse.jpg
http://img.photobucket.com/albums/v641/rjakubin/T-Line.jpg
Also one was fully stuffed and the other partially stuffed. The fully stuffed version sounded better in the long run.
http://img.photobucket.com/albums/v641/rjakubin/tl-sub-fr-1.gif

Measurements: Line length 96" - Height 32 1/2" Width 9 or 11" Depth - Bottom 16 1/2" Top - 14 1/4"...

The 11" wide baffle i had 2 - Dayton 10" Classic woofers in them;
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=295-315&ctab=2#Tabs

I was pretty disappointed in them. They graphed just like the Dayton 8's. If you look at the specs they're identical except for cone area. So now I'm switching to these next month (Oct.);
http://mcm.newark.com/NewarkWebCommerce/mcm/en_US/endecaSearch/partDetail.jsp?SKU=55-1740&N=0
Each speaker has a sensitivity of 95 db, so 2 in parallel should give me close to 101 db. They also modelled well in MJK's workshett, so no changes have to made to the box.

Back to the Dayton 8's. I later replaced them with the new RS 8's;
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-366
With more Xmax I got a better bass sound then the Classic's. I paired these up with the Dr K's;
http://www.partsexpress.com/projectshowcase/dr-k-mtm/index.html
Some time in the next few months, I'll pair them up in the 9" baffles with these speakers;
http://mcm.newark.com/NewarkWebCommerce/mcm/en_US/endecaSearch/partDetail.jsp?SKU=55-1735&N=0
They're rated at 96 db. Just to experiment.
I find myself pushing the woofers in the T-Lines pretty hard at times and the Xmax can't take it.

If you decide to build a set, I'll try and put the boxes in a drawing with the board sizes and placement.

 

[bhg41088]

I want you to post the dimensions of the fully stuffed box for the 2 eights. Thank you, Ben.

 

[GM]

Using Martin Kings Mathcad program for ML TQWT I got these results for 2 8" Dayton Classic woofers.
Fd=29 hz.
Vad = 57.76
Qed = .44
Qmd = 3.23
Re = 3.4
Lvc = 1.5
BL = 11.49
Sd = 324

Greets!

FWIW, based on PE's measured specs I get these summed specs for two, with Bl recalc'd based on MJK's WS's 'po', 'c' values:

Fd = 32.86
Re = 3.4
Lvc = 1.505
Bl = 11.6795
Sd = 412.24
Vad = 57.74
Qed = 0.51
Qmd = 3.43
Qtd is auto calc'd

GM

 

[GM]

I've seen a couple of those before... my worry has always been how big the sample set of devices was (ie is this applicable to my meter or only the one measured)

Anyway here is a before & after adjustment for the meter deviation as given

dave

Greets!

I'm aware of three distinctly different correction curves based on individual units only. Mine, which is based on a comparison to a borrowed GE instrument test labs calibrated meter. Tom Danley's, which was compared to a TEF machine's measurements, and DLC's Eric Busch's lab measurements (the folk's who brought us DUMAX).

Bottom line, take any of them with a 'grain of salt' WRT your meter IMO, but they're still an accurate inexpensive unit for comparative tests.

GM

 

[bhg41088]

RJ, can you please post a drawing with board sizes and placement for the medium stuffed 2 8" TL? Thank you!

 

[bhg41088]

I decided to go with the one fold design. http://www.diyaudio.com/forums/attachment.php?s=&postid=581259&action=thumb&stamp=1109058950

I was wondering if there is any stuffing advice i should know. Also, could i place both speakers on one side? The fold was called " so-so," Should i change it? Thanks guys.