Yes but, FR willing, I could try higher xover points like you've suggested.
5.5" x 26" - with the rear reflections the directivity must be complex at some point. The PPMSL seeks to mute the rear reflected signal, and hopefully improves the result. I remembered that HR has a simulator, and did my best to sim my Slot from a side view. I seems that anything below the mouth frequency is fair game? I am not sure if I did it right, though, I think each square equals a centimeter.
13550/26= 521.15hz
One thing that I also found relevant that doesn't get talked about much is the relevance of Qes/Qts. I'm my time simulating I've come to see the connection to resonance vs speaker Q. I see why we consider the same driver traits that are desired for a horn driver as traits of the best woofers. Powerful motor and low Q. The lower Q of the driver, the more it dampens the resonances of the enclosure.
Can it prevent the ‘pipe’ from going into full rEtArD mode?
(Ring/honk, decay, puke, etc)
(Ring/honk, decay, puke, etc)
This is not true. Have a look at the loudspeaker equivalent electric model where the Qts comes from.
Whatever the best case scenario is, you will achieve it with a lower Qts.
Or just do is I did and play around with Qes in HornResp.
Sure, it's just because I have too much users everywhere and I'm reducing them. I already got some images from google for PM design.
Check out the B&C18ds115 (0.18 qts) verses another good B&C 18 (or any brand) with a 0.3 or so Qts? The ds115 goes bat sh!t crazy and needs EQ in everything it seems?
https://www.parts-express.com/pedocs/specs/294-6028--bc-18ds115-4-spec-sheet.pdf
18sw115 looks a lot better when the ds series do a heavy bat wing response.
Tada tada tada
Tada tada tada
Tada tada tada
Batmaaaaannn!
Tada tada tada
Tada tada tada
Tada tada tada
Batmaaaaannn!
Is it because the ds115 needs a ‘smaller’ box? it’s certainly ‘damped’ and low ‘Qes/qts’?
What’s the suspension stiffness on the SW driver? Is it a combo of these things that creates the dribers that aren’t so goofy at resonace (s)?
Are we driving an empty dump truck with an insane spring rate that the oil in the shocks can’t even control? Boing! Boing! (With the ds115 series)
What’s the suspension stiffness on the SW driver? Is it a combo of these things that creates the dribers that aren’t so goofy at resonace (s)?
Are we driving an empty dump truck with an insane spring rate that the oil in the shocks can’t even control? Boing! Boing! (With the ds115 series)
I didnt mean qes divided by qts. Qes and Qts.... I just look at Qes to be honest.
Yes. Intermodulation distortion is proportional to the excursion. (well in this context, there are other types as well)
So there are two things we can do:
- make the motor super linear with all kinds of tricks.
- make sure we just have very little excursion to begin with.
In the 2nd case we end up with only HD distortion + maybe some additional cone resonances/issues
(although they very often will show up in HD distortion).
Also, BL(x) is far more important than Kms(x) -> See Klippel papers.
This is even (a lot) more true for a woofer that does low-end + mid-range.
The only thing that is left is a bit of Le(i) and some general distortion from the magnet system. (to explain it in simple words)
But that can just easily been measured and in general is not as destructive as IMD.
i which case we need to add more cones ( drivers ) to hit target SPL as with very little excursion we get very little SPL,
but we will have an indestructible system, no burnt drivers
the drivers will be cool as a lettuce in the fridge 😀
The HO version of that Dayton RS looks like it would have a stronger motor and better TSPs for better low end extension. Have you used these before?
Yes.....the cone sometimes oil cans or 'pop's when in a high Q box.....i no longer recommend them
Thats an awful sound when a large driver cone buckles. I'm not a fan of aluminum cones for 15" + woofers for these and other reasons. I dont like small high compression direct radiating enclosures with a few exceptions. These Dayton drivers are not on par with other name brand PA sub drivers with their heavily reinforced cones and double spider suspensions. These features are mandatory for any serious LF applications, especially FLHs and 4th order bandpass.
FWIW, modeling a BR enclosure as an offset TL and using that sim to play around with box size and vent dimensions does work, and I've done just that with three builds. The trick is to ensure that you're measuring effective path lengths and segment cross-sectional areas correctly. This does introduce some limitations to the box layout to remove the guesswork.
An example of one such build is my "Boom Unit", at https://www.diysubwoofers.org/projects/home/boomunit/ and
another example is my POC #6, at https://www.diysubwoofers.org/projects/other/POC6/
I do also have a spreadsheet that models a "standard" shelf-vented BR as an offset TL with stepped segments, but I haven't built an enclosure yet to determine how accurate it is.
An example of one such build is my "Boom Unit", at https://www.diysubwoofers.org/projects/home/boomunit/ and
another example is my POC #6, at https://www.diysubwoofers.org/projects/other/POC6/
I do also have a spreadsheet that models a "standard" shelf-vented BR as an offset TL with stepped segments, but I haven't built an enclosure yet to determine how accurate it is.
sometimes i wonder why we even bother adding that interior panel that only serves to create another resonance(thats not excited because of the driver position we sort of gamble on)?
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