Hello,
I'm looking for driver options for a pair of N-profile Ripoles. I'll use one or two drivers per box if needed.
My understanding is that they will need a fairly large Xmax. I'm also looking for high efficiency, so a pro driver is fine.
Fs need not be rock bottom, as this alignment will lower the resonant frequency a bit. Basically looking for an F3 (when done)of about 30Hz to 36Hz.
Not really a subwoofer, but a singular bass speaker
Also, if anyone knows of a good program to model these with, I'd appreciate it.
For anyone confused or doesn't know what a N-profile is, I've attached a sketch of the box shape:
I'm looking for driver options for a pair of N-profile Ripoles. I'll use one or two drivers per box if needed.
My understanding is that they will need a fairly large Xmax. I'm also looking for high efficiency, so a pro driver is fine.
Fs need not be rock bottom, as this alignment will lower the resonant frequency a bit. Basically looking for an F3 (when done)of about 30Hz to 36Hz.
Not really a subwoofer, but a singular bass speaker
Also, if anyone knows of a good program to model these with, I'd appreciate it.
For anyone confused or doesn't know what a N-profile is, I've attached a sketch of the box shape:
Attachments
Not much of a response. Not a popular alignment, I know, but one that can give exceptional results for music.
I'll start the ball rolling. I've looked at quite a few different drivers with an eye on a few key points: price - I won't spend more than $250.00 on any driver. Efficiency - needs to be high. Xmax - has to be enough excursion to provide high SPL at low freq. Vas - TBH, I'm not sure. Is a stiff suspension better or loose one perform better?
One driver that got my attention is the Basslite C2515 from Eminence. It is below $200.00 here, It has high sensitivity at 98db, Xmax is a decent 4.5mm (considering the expected freq range of the speaker and it's size, thats pretty good).
Full specs are here:
http://www.eminence.com/pdf/basslite-c2515.pdf
I'll start the ball rolling. I've looked at quite a few different drivers with an eye on a few key points: price - I won't spend more than $250.00 on any driver. Efficiency - needs to be high. Xmax - has to be enough excursion to provide high SPL at low freq. Vas - TBH, I'm not sure. Is a stiff suspension better or loose one perform better?
One driver that got my attention is the Basslite C2515 from Eminence. It is below $200.00 here, It has high sensitivity at 98db, Xmax is a decent 4.5mm (considering the expected freq range of the speaker and it's size, thats pretty good).
Full specs are here:
http://www.eminence.com/pdf/basslite-c2515.pdf
Hi Dave,
Similar subjects (W Ripole, dipole). Lots of good info on the moray james thread, but not specific to the N profile.
In particular, I'm looking for a simulation program. I've considered trying to use MJK's worksheets but I can't say that I'd trust the result, though it might be useful for excursion predictions.
Maybe a real world test is in order. What's your opinion on the speaker I mentioned above?
Similar subjects (W Ripole, dipole). Lots of good info on the moray james thread, but not specific to the N profile.
In particular, I'm looking for a simulation program. I've considered trying to use MJK's worksheets but I can't say that I'd trust the result, though it might be useful for excursion predictions.
Maybe a real world test is in order. What's your opinion on the speaker I mentioned above?
Very nice Dave. How did you determine the dimensions of the box? These Fosters, what are the T/S specs, in particular the Qts?
Once again a W-profile (though there are big benefits of the opposing drivers canceling mechanical movement) I'm looking for a slimier, less cubical shape in the N-profile.
I may go to the extreme of buying a driver (the Basslite) and trial and error a box. I have a spare (yeah, not 14!) 12" here doing nothing that I could test, but I want to do this for keeps.
NO idea how this could be accurately simmed?
Once again a W-profile (though there are big benefits of the opposing drivers canceling mechanical movement) I'm looking for a slimier, less cubical shape in the N-profile.
I may go to the extreme of buying a driver (the Basslite) and trial and error a box. I have a spare (yeah, not 14!) 12" here doing nothing that I could test, but I want to do this for keeps.
NO idea how this could be accurately simmed?
Dave,
Consulting with Bjorno on this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=107957&pagenumber=2
He ran some simulations with MJK's BLH Sections worksheet to get tentative results.
I have used the open end TL worksheet to get a rough idea of the output. Using the Basslite speaker specs and a line length of 18", I came up with these charts.
The section area (So - Sl) is Sd*1 for the top, Sd*.5 for the middle and Sd*.25 for the bottom.
Looks like a bigger section area give better higher freq response and also improves step response.
Downside, is larger section area, higher the Fs peak.
Once again, can these results be treated as accurate?
Consulting with Bjorno on this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=107957&pagenumber=2
He ran some simulations with MJK's BLH Sections worksheet to get tentative results.
I have used the open end TL worksheet to get a rough idea of the output. Using the Basslite speaker specs and a line length of 18", I came up with these charts.
The section area (So - Sl) is Sd*1 for the top, Sd*.5 for the middle and Sd*.25 for the bottom.
Looks like a bigger section area give better higher freq response and also improves step response.
Downside, is larger section area, higher the Fs peak.
Once again, can these results be treated as accurate?
Attachments
Hi,
to my taste these are inaccurate. At least the freq-range above the first resonance is not as I know from praxis. I´m not familiar with those sheets and haven´t used them yet, but the folded dipoles definitely show other frequency responses....in my own simulation as well as in praxis.
Since from the range above 100Hz only the area around the first resonance is of importance the sheet might be usable if it models the range below 100Hz and the position and strength of the first resonance correctly. Assuming that the blue curve is the amplitude and red for the phase it could be ok. At least the tendency regarding the freq-response depending on the dimensions of the chambers is correct.
As for the driver-Q...please use the search function. Sorry to say, but there are enough and precise enough answers given in several threads already and I´m just not in the mood to repeat myself each and every week again and again (I guess this holds true for anybody else)
jauu
Calvin
to my taste these are inaccurate. At least the freq-range above the first resonance is not as I know from praxis. I´m not familiar with those sheets and haven´t used them yet, but the folded dipoles definitely show other frequency responses....in my own simulation as well as in praxis.
Since from the range above 100Hz only the area around the first resonance is of importance the sheet might be usable if it models the range below 100Hz and the position and strength of the first resonance correctly. Assuming that the blue curve is the amplitude and red for the phase it could be ok. At least the tendency regarding the freq-response depending on the dimensions of the chambers is correct.
As for the driver-Q...please use the search function. Sorry to say, but there are enough and precise enough answers given in several threads already and I´m just not in the mood to repeat myself each and every week again and again (I guess this holds true for anybody else)
jauu
Calvin
Calvin said:
Wow. It would have required a lot less effort for you to type either "high" or "low" as an answer regarding driver Q. You would rather see a member search (maybe for hours) to find this information.
Thanks for the high quality help you are offering but with all due respect, stuff it.
Hi,
I was already the second who suggested You to use the search function, since there is a lot of very precise and useful info to find that doesn´t need to be rewritten again and again.
Since I normally try to give precise answers and infos, I refuse to give values like ´low´ or ´high´ when they are simply not appropriate.
But because of Your oh so friendly way, I follow Your suggestion and stuff it.
jauu
Calvin
I was already the second who suggested You to use the search function, since there is a lot of very precise and useful info to find that doesn´t need to be rewritten again and again.
Since I normally try to give precise answers and infos, I refuse to give values like ´low´ or ´high´ when they are simply not appropriate.
But because of Your oh so friendly way, I follow Your suggestion and stuff it.
jauu
Calvin
Calvin said:
Have a quick look around with your eyes wide open to notice how many subjects are rewritten over and over. If you have something helpful (or even entertaining) to say, then say it. Otherwise, say nothing.
It should be plain from my friendly way (brought on by your unhelpful attitude), that I neither want or need your advise.
MJL21193 said:
I think the answer is "moderately low Qts" ..0.4 or so . For example, the specs for the "original" driver used for ripoles can be found here http://www.lautsprechershop.de/hifi/index_en.htm?/hifi/ripol_en.htm
Let's not get further into mudslinging. IMHO, the search engine on this forum is less than optimal (or I don't know how to use it) for complex queries but as a result of searching, I invariably end up learning a lot more, in addition to my initial query , .. so it's all good . Also, there's always google too, since this site is open to their search engine.
Peace
zobsky said:
Thanks Zobsky. Was that so difficult?
The site you pointed to I've already visited, along with many threads on this forum. It's good to hear as many perspectives as possible.
I agree, the search results can be daunting. Sometimes, a search will lead to the point where I've forgotten what I'm looking for..
A fine example how urban myth´ emerge!
I know from first hand that the people of lautsprechershop asked Axel to compute the best ripole dimensions and filter for this given driver. And that he did! So it is NOT "the original driver" NOR the best driver. But simply a decent one at a competitive price (in Germany at least).
@MJL21193
If you need a guideline: Almost everybody agrees that the Peerless SLS series drivers have very appropriate parameters at a decent price.
If your target is a fully passive system at a budget, the Eminence Alpha 15A with Qts>1 might be a perfect solution. If you have all means of electronic equalisation, a Beyma PA driver with a low Qts might be the best answer because of its more sophisticated motor, cone and built quality.
You can tweak a W baffle and driver combination in many ways, so why insist on a narrow "standard" design?
Rudolf said:
Hi Rudolf,
The SLS drivers are in my price range, but I would really like a higher efficiency (>95db). These will be for music only to augment the base from a pair of sealed 3 ways. They will be driven from a separate amp with an active filter.
The w baffle requires 2 drivers, yes? That would be 4 drivers for 2 units. I also want these as slim and compact as possible.They will be located close to the sealed 3 ways.
Have you looked at the Eminence woofer I linked to above? Does it have potential, in your opinion?
Just my curiosity: If you drive those drivers from a separate amp, why do you want a higher efficiency? You NEED to run out of excursion before running out of electric power. If not, your amp is too weak. In a dipole configuration your limiting factor is Xmax, but not efficiency.
Your N-profile is just a half W baffle. But the benefit of impulse compensation in a W baffle is huge. I learned that when I cut my first W baffle in half to make it stereo.
If you are going with 15" drivers you might start mono with a single W baffle with two drivers. Could easily be enough bass if you don´t want it for HT.
There is no box configuration with less volume requirement than a Ripole.
From the data sheet it looks fine (in my opinion). What I can´t judge from the paper: Is the pole vent big/quiet enough? And is the small resonance/breakup (?) just below 200 Hz something to consider or not? Since the w baffle s for bass augmentation only, I believe you will cut it below 100 Hz.
Hope this gives some guideline.
Rudolf said:
This is true, and the amp will have enough power. The Peerless 830669 (12") is $75.00 here. Maybe 4 of these, 2 W-profile if I could keep the boxes relatively small.
These will be to supplement the sealed active pair here:http://www.diyaudio.com/forums/showthread.php?s=&threadid=106736&pagenumber=4
Not for home theater bass. For that I have a bigger sealed, EQ'ed sub (two 18" drivers) shown below.
Thanks.
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