Merci, je possède des hauts-parleurs SEAS depuis 25 ans
Yes you can use a U18 in a closed box but the problem will be the bass extension f3=100Hz. If you have a sub, no problem.
If you want go full-range without the sub, you should have a reflex port and with the sub you have to close the port.
It is possible to build small closed box speaker but with low sensitivity, you have to find the good driver.
For example the SEAS L16RN-SL 12L f3=60Hz Scan-speak 15w-8530k01 15l f3=60Hz
Yes I will do reflex port if I go for the U18 in a 10L box. I will look at those other drivers for a sealed box, thank you!
F(-3) is not a useful number for humans (ref Toole) — it is useful to know if he chooses to use the sub he doesn’t want to use. . What is F(-6) and F(-10)?
dave
I’ll probably get a lot of flack, nut i note that a typical circular cyclinder vent (ie plumbing pipe) does not offer as much control of the bottom as a more resisiive vent. The way i do it gives up a bit of bass extention for greater control, more aesthtic bottom as the extra R seems to make the box more tolerant to dynamic shifts of T/S parameters.
ie besides just bad design, that the changes in T/S due to dynamics (in the music or where you have the wick set) is one of the reasons BRs get a bad rep.
I believe it was My Mayhem suggests if it can’t do 42 Hz sealed, forget about it. I differ with him. I have a bunch of really good sounding boxes with holes in them.
dave
Yes I heard that I should be looking at F(-10) instead of F(-3). If my understanding is right, -10 is about half of 0 in terms of db right? (If I choose that Curv woofer I will be using a port anyways so no need to find the F10 for this one in a Sealed enclosure. Ported the F10 is around 38
This is very interesting to read Dave, ideally my port would be a rectangular one at the very bottom (approx 0.75 inches by 7 inches) similar to the TAD Reference One). I need to figure out how they calculated their port tho as per this image I am attaching. It doesn't seem calculated like a regular port.
The picture is not that clear… it is not a simple rectabngular vent. Either some exitiuc modeling or a lot of cut and try and measure. Likely the latter.
The vent you plan is of an aspect ratio that should add some R if long enuff. A standard modeler can’t deal with this, over some 2 decades of miniOnkens there is an extrapolation that i make with the sim.
dave
The vent you plan is of an aspect ratio that should add some R if long enuff. A standard modeler can’t deal with this, over some 2 decades of miniOnkens there is an extrapolation that i make with the sim.
dave
Thanks Dave, that does sound complex. Do you know if engineering softwares could model this? I have a few friends who use mechanical engineering softwares thay calculate every detail. I don't know if those softwares can do air movement but I would imagine it could be possible if some parameters were set. I wonder if grasshopper in Rhino could do something too, I am familiar with that one as a B. Architect. If not, do you think I can pull a similar design off with a simple rectangular port designed in a similar manner? Btw please, what do you mean by "R"?
Maybe. But it might need one of the $mega/year sw packages like Cosmol or such with the acoustics package.
The long high-aspect ratio ventsi use have been shown to work pretty well.
dave
Yes, and you don't need fancy shmancy software to model the behavior.
Look like the U18RNXP will work with 6 vents (2.0" x .375" x 9.7" long) in a 17 Litre box, tuned approx. 44Hz.
Okay thanks, I will look into this.
I'm glad to hear this, thanks
I have been looking at tweeters that could crossover a bit lower. Aurum cantus offers an amt that is on sale at parts express right now, or audax offers an interesting gold tweeter (but supposedly it is very harsh). I also read that ribbon tweeters may be a bit "thin" sounding in their lower frequencies. What kind of tweeters would you choose if you had to crossover pretty low? Between 1.5k and 4k. Thank you.
Last edited by a moderator:
Above 3k you have a lot of choice of tweeters.
2-3khz A narrow choice
Below 2kHz the choice is very limited.
If you want to use a dome till 1.5kHz , I would use
SEAS T29 Crescendo
SB Acoustics TW29 beryllium
Hmm, so if I want to use the Seas 5" Magnesium drivers, I should probably consider a midrange and a tweeter on top. That would start being a little expensive I think. I could design tweeter on top of cabinet like B&W does. It would be interesting, but maybe too expensive. I have a friend who is a retired audio engineer that worked for Genelec, he said the Seas Excel Magensiums are excellent drivers, so I would really like to use them. But they go max 2.5k I believe, and if I read the comments on this discussion properly people recommend crossing them over lower. My other option is just to use those Curv 7" woofers which crossover much higher, around 4k max. I could even probably go for an Aurum Cantus ribbon tweeter as I originally intended. I know you seemed to recommend the 7" curv over the 5" magnesium due to size, do you think the 5" magnesium is better in any aspects due to it being an Excel woofer? Thanks
That's a nice curve, thanks for modelling it. What does Xmax look like?Yes, and you don't need fancy shmancy software to model the behavior.
Look like the U18RNXP will work with 6 vents (2.0" x .375" x 9.7" long) in a 17 Litre box, tuned approx. 44Hz.
View attachment 1324253
This might be the driver to go with then. I am still very much considering the Excel driver but I am not sure if it is all that better then this prestige driver, and it would cost me a fair bit more. Plus I get more surface area with this one. Thanks again!
It's pretty well behaved too. I noticed in the Idunn 2-way kit that's on the Madisound site, they're only using a 2nd order low-pass for it.
jeff
About this behaviour, I know you and @planet10 disliked the behaviour of the Seas Excel 5" Magnesium. If you don't mind me asking, what do you look for when you judge the behaviour? I spoke to a guy who previously worked for genelec and he said the Seas excel drivers are very good and that I should keep in mind that those graphs are measured without an enclosure and in a anchovie chamber. All of this may as well be hieroglyphs to me at the moment but i would love to learn.
*ancheoic chamber or whatever that is called