ultrachrome said:
Page 2 of this thread
I said;
snip...
Hypothetical;
If you can fit a TD15, it models well in a 4 to 5 cu. ft. box tuned
to 35hz. I have the TD15H which is the lowest Q woofer, the
TD15X is the medium Q. Either way, they model close. I tried the
TD15 in a sealed box, then ported. The woofer shines in the
ported box because....
1. More clean bass output due to the ported design.
2. Cone excursion is less near tuning which means less cone
movement which means less modulation of the midrange frequencies which means better sound and less woofer abuse.
To make the ported box sound best, my test box had dual 4"
flared Precision Ports on the back of the box. There was no
port noise because it's oversized. I can rattle the house with
just one TD15, two would be plenty.
The TD12 doesn't model as well as the TD15, 3 cu. ft. box tuned
to 45hz isn't bad, or 5 cu. ft tuned to 40hz. "
....
If you want a sealed box, estimate 1 cu. ft. less. Do a WinISD
to check it out or tell us exactly how much air space you have
to work with.
You need to finalize your plan in regard to using a subwoofer
or not. That can change the design. If no sub, go ported but
the box is bigger. If sub, go sealed to shrink the design a bit.
But if it was me, I would do ported plus sub because I tend to
push my speakers hard and you get more excursion out of
the sealed box which modulates the great sounding midrange
you get out of them. For a normal person, it wouldn't matter,
but if you are power user the little difference is audible.
I was asking because the WinISD "suggested" enclosure size is very small. It didn't seem right. Here's my plug-and-play results. I added the SEAS driver from my Ellis onto the graph in orange for comparison.
The TD15 modeled much nicer and seems like it would provide a speaker that would sound good with or without a sub. The TD12 looks like it's going to sound very thin and will require a sub.
If I'm going to need a sub, why not go for a 10?
What about some linkwitz transform on the TD12? Would that be a detriment to its higher octaves?
An externally hosted image should be here but it was not working when we last tested it.
The TD15 modeled much nicer and seems like it would provide a speaker that would sound good with or without a sub. The TD12 looks like it's going to sound very thin and will require a sub.
If I'm going to need a sub, why not go for a 10?
What about some linkwitz transform on the TD12? Would that be a detriment to its higher octaves?
I wouldn't be surprised if real-world F3 was more like 50-60Hz, which is low enough to be quite authoritative. A sub never hurts, but it's surprising how good such a loudspeaker can be without one.
It sounds fine, but I'm not sure I would pick this as the first choice. I do like the sound of a 12" driver handling the midbass though, so I'm not sure I'd go back to a small woofer either. Probably a little more EQ would help - IIRC the 12CX has a rising response around 800Hz that showed up with a 2nd order XO, and messed with the PR17's output around 1kHz. I ended up going with 4th order slopes partly to take care of this.
3ft^3 at 45Hz doesn't look so bad. How audible is that depression? In other words, how flat does it have to model?
An externally hosted image should be here but it was not working when we last tested it.
Have you considered using the TD12S instead of the TD12X?
With 91liters (3.2 cuft) and a 36hz tuning, you get an F3 of 40hz.
With 91liters (3.2 cuft) and a 36hz tuning, you get an F3 of 40hz.
How audible is that depression?
I wouldn't worry about that, too minor. Things change
as soon as you factor in room gain and/or and EQ.
But the ported box is much nicer on the TD12.
Once you figure out which path to take, make the test box
for the woofer only using scrap wood and do a bass test
in the house to make sure you like the sound. Don't build
the final product until you verify. If you are really picky about
the low end, then maybe model the TD12 using passive radiators,
maybe a single 15" or dual 15" radiator on the sides of the cabinet. I was reading some archived Lambda info and Nick
really liked the side mounted PR's for SQ reasons plus some
cabinet stuffing to tame the midrange exiting the PR. The PR
design is more critical and it cost more ... If TD12 plus dual
PR's, then makes you wonder why not TD15 plus ported as
the price may be cheaper. /food for thought/
John sells PR's for $75 each. /heh/
http://yellow.mynethost.com/~bv1263...id=42&osCsid=47cc330430d08b0d5f8887e8ec1623b7
Xmax 2 inches......
Or TD15 plus dual 15" PR's if you want to get mad
I think WinISD pro models PR's, you have to play with it to
see how it works.
I wouldn't worry about that, too minor. Things change
as soon as you factor in room gain and/or and EQ.
But the ported box is much nicer on the TD12.
Once you figure out which path to take, make the test box
for the woofer only using scrap wood and do a bass test
in the house to make sure you like the sound. Don't build
the final product until you verify. If you are really picky about
the low end, then maybe model the TD12 using passive radiators,
maybe a single 15" or dual 15" radiator on the sides of the cabinet. I was reading some archived Lambda info and Nick
really liked the side mounted PR's for SQ reasons plus some
cabinet stuffing to tame the midrange exiting the PR. The PR
design is more critical and it cost more ... If TD12 plus dual
PR's, then makes you wonder why not TD15 plus ported as
the price may be cheaper. /food for thought/
John sells PR's for $75 each. /heh/
http://yellow.mynethost.com/~bv1263...id=42&osCsid=47cc330430d08b0d5f8887e8ec1623b7
Xmax 2 inches......
Or TD15 plus dual 15" PR's if you want to get mad
I think WinISD pro models PR's, you have to play with it to
see how it works.
akunec said:
The assumption was that John was only building the X versions
of woofers. You have to call him and find out if he can build
the X, H, or S version of TD. If so, then you can fine tune the
design. 🙂
Forgot to mention. John is also very knowledgeable in loudspeaker design and if you are interested in buying those
woofers he can also offer some ideas for your box design.
He has worked with the TD12 and he has PR experience.
Talk to him and report back with this ideas, then compare
notes. 😎 If you are going to do this project, try to make
it the best 😀
woofers he can also offer some ideas for your box design.
He has worked with the TD12 and he has PR experience.
Talk to him and report back with this ideas, then compare
notes. 😎 If you are going to do this project, try to make
it the best 😀
UltraChrome,
Have you already decided to go with a boxed woofer? I love the sound of my open baffle PR so much I think I've decided to go with a dipole woofer to get the same feel from the bass/midbass. I originally started playing them open baffle just to break them in a bit but now I don't think I could go back to "boxed" speakers.
Just something to think about...
--Chris
Have you already decided to go with a boxed woofer? I love the sound of my open baffle PR so much I think I've decided to go with a dipole woofer to get the same feel from the bass/midbass. I originally started playing them open baffle just to break them in a bit but now I don't think I could go back to "boxed" speakers.
Just something to think about...
--Chris
Well I plan to run the PR170 OB. I'm all for open baffle woofers even knowing that I'll have to rely on EQ and a sub. It's a tradeoff I accept. If I'm going ported, I want deeper extension. The TD15 gives me that but at the expense of a baffle width that will likely cause premarital strife.
I've been playing with WinISD because it's been an easy way to compare drivers.
Keui suggested an open baffle set of 8" Audax woofers that was really interesting but I was nervous about what to do with all those woofers if I didn't like the end result. What's the best tool to quickly model single and multiple open-baffle woofer arrangements?
I've played with the MK worksheets but I'm in a little over my head with those. I'm not sure what all those different graphs are telling me and I haven't had time to go through the diyaudio archives.
I've been playing with WinISD because it's been an easy way to compare drivers.
Keui suggested an open baffle set of 8" Audax woofers that was really interesting but I was nervous about what to do with all those woofers if I didn't like the end result. What's the best tool to quickly model single and multiple open-baffle woofer arrangements?
I've played with the MK worksheets but I'm in a little over my head with those. I'm not sure what all those different graphs are telling me and I haven't had time to go through the diyaudio archives.
Konnichiwa,
You might want to try the Worksheet I designed (xlbaffle.xls). This takes into account a certain degree of room influence. It predicts generat trends pretty well. There is a reasonbaly high fudge fator in that (so don't expect better than +/-3db accuracy) but in practice correlation is pretty good.
To simulate multiple drivers you can adjust Re as I did in the example I showed earlier....
Sayonara
ultrachrome said:
You might want to try the Worksheet I designed (xlbaffle.xls). This takes into account a certain degree of room influence. It predicts generat trends pretty well. There is a reasonbaly high fudge fator in that (so don't expect better than +/-3db accuracy) but in practice correlation is pretty good.
To simulate multiple drivers you can adjust Re as I did in the example I showed earlier....
Sayonara
ultrachrome said:
If you use an H-Baffle its much more wife friendly.
For Example, an 18" wide, 2 foot deep Hbaffle with the drivers mounted 1/2 way back gives an effective baffle width (for diffraction) of (12"+18"+12") = 42" and an effective path difference for dipole cancelation of (12"+12"+18"+12"+12") or 66" All this while still only measuring 18" wide 8)
ultrachrome said:
I've been using the dipole.xls from the diysubwoofer website. It allows you to model the woofers with Qts adjustment as well as lopwpass/highpasss filtering and active EQ.
I've attached it to this post, it also has some of my perlimenary work with the Beta 15 on there...
--Chris
[EDIT:] The XL-baffle mentioned above is also very good, I've been using that as well.. From pure TS specs the Eminence Beta-15 and Alpha 15 look like winners in an 18" wide, 36" high, 24" deep h-baffle, and it would act as a perfect height stand for the mid/tweet panel I've designed 🙂
I've emailed John to see what he thinks.
Since my employer blocks wayback machine but I've now got my EDGE enabled cell phone connected so I can get to the wayback machine.
What about the Lambda Dipole drivers? The 10 and 12 both have a Qts of .68. A pair of 12's in WinISD for fun show a killer response...in a 238 cubic foot box. Isn't that essentially an OB response without accounting for baffle-width-induced-roll-off (BWIRF)?
orange=2*Dipole12
green=1*TD12X ported
yellow=1*TD12X sealed
Since my employer blocks wayback machine but I've now got my EDGE enabled cell phone connected so I can get to the wayback machine.
What about the Lambda Dipole drivers? The 10 and 12 both have a Qts of .68. A pair of 12's in WinISD for fun show a killer response...in a 238 cubic foot box. Isn't that essentially an OB response without accounting for baffle-width-induced-roll-off (BWIRF)?
orange=2*Dipole12
green=1*TD12X ported
yellow=1*TD12X sealed
An externally hosted image should be here but it was not working when we last tested it.
What about the Lambda Dipole drivers?
From what I've read, Lamdda stopped making their dipole
woofers long ago and ran out of stock.
But John has a dipole woofer based on the Lambda LE motor.
The LE motor is not faraday motor.
Do you need the faraday motor? Only if you want the best
sound at the higher band.
If you low pass at a lower crossover it becomes hard to
notice the difference. Nick claimed the LE was good up to
300hz. The faraday up to ~2khz. To the trained ear, he
could still distinguish between the two at a lower low pass.
How picky are you?
AE Speakers IB15
http://yellow.mynethost.com/~bv1263...id=50&osCsid=c9cfa3dbccf1a45d3a6db1c07c68ceac
Have you search this forum yet?
http://f20.parsimony.net/forum36475/thread.htm
I'm sure you can dig up users who have used the IB15,
get some feedback from them.
From what I've read, Lamdda stopped making their dipole
woofers long ago and ran out of stock.
But John has a dipole woofer based on the Lambda LE motor.
The LE motor is not faraday motor.
Do you need the faraday motor? Only if you want the best
sound at the higher band.
If you low pass at a lower crossover it becomes hard to
notice the difference. Nick claimed the LE was good up to
300hz. The faraday up to ~2khz. To the trained ear, he
could still distinguish between the two at a lower low pass.
How picky are you?
AE Speakers IB15
http://yellow.mynethost.com/~bv1263...id=50&osCsid=c9cfa3dbccf1a45d3a6db1c07c68ceac
Have you search this forum yet?
http://f20.parsimony.net/forum36475/thread.htm
I'm sure you can dig up users who have used the IB15,
get some feedback from them.
Cool. Hopefully John will have the same answer. I rechecked his Lambda post and he does offer the dipole versions. Then I can satisfy everyone!
Thanks diy_newbie, I'll play with that spreadsheet tonight. Unfortunately the 18" baffle is just too wide.
Much thanks!
ultrachrome said:
If you're e-mailing John see if he'll give us a discount like he's running on the IB15s if we buy one big order.. I could go for 2x or 4x Dipole 12 or Dipole 15s if the price is good...
Their running the IB15s for $100 each if you buy 4 at a time but john recommended I not run the IB15 much higher then 150hz... I would really like to roll of the PR170 around 250hz if possible, when I added a LR48 at 250hz it really took the strain off the midrange.. So I'd like to find a woofer that could play diple 250hz and under.
--Chris
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