I am looking to build a pair of sonotubes using Seas L26ROY-drivers and I can get a tube cheap from a nearby vendor.
I have a couple of Q's though:
Is it a negative thing to make the volume bigger than WINisd suggests? The program wants 36.5 litres, for practical reasons 60 litres would suit me better.
Are there any demands when it comes to wall thickness of the tube? The tube I can get is 0,18 inches or 4.5 mm wall thickness. (1/5,5 inch.)
Thanks to all repliers!
Driver info: http://www.seas.no/index.php?option...le&id=400:d1001-04-l26roy&catid=94&Itemid=501
I have a couple of Q's though:
Is it a negative thing to make the volume bigger than WINisd suggests? The program wants 36.5 litres, for practical reasons 60 litres would suit me better.
Are there any demands when it comes to wall thickness of the tube? The tube I can get is 0,18 inches or 4.5 mm wall thickness. (1/5,5 inch.)
Thanks to all repliers!
Driver info: http://www.seas.no/index.php?option...le&id=400:d1001-04-l26roy&catid=94&Itemid=501
If it is sealed, your QTS is going to drop, say .707 to a value towards 0.5 ....which is OK, if you like your "impact" of Bass tones...at the sacrifice of lower-end extension.
If it is calculated as a ported enclosure, your tuning (fb) will be "out of spec".
If it those big sewer-pipes of PVC, they are rather inert & strong....they can "ring" a bit I'd guess, nothing a good stuffing won't damp out.
--------------------------------------------------------------Rick.......
If it is calculated as a ported enclosure, your tuning (fb) will be "out of spec".
If it those big sewer-pipes of PVC, they are rather inert & strong....they can "ring" a bit I'd guess, nothing a good stuffing won't damp out.
--------------------------------------------------------------Rick.......
Last edited:
Your SIM should give you an fb, or tuning frequency, a specific volume of enclosure to match up with this frequency, Vb . Further, your sim should give you a port diameter & length, (remember to compensate your Vb accordingly).
You should have low-end performance screen as calculated, say -3.08Db@33.58 hz.
with your sim you can redo your tuning, bobbing your fb and Vb in any configuration you want....& watch how it "builds" your response curves.
___________________________________________________Rick........
You should have low-end performance screen as calculated, say -3.08Db@33.58 hz.
with your sim you can redo your tuning, bobbing your fb and Vb in any configuration you want....& watch how it "builds" your response curves.
___________________________________________________Rick........
I understand it partly. I see the vent length changes as I change volume and tuning frequency.
With 60 litres and 25 hz tuning the graph show a slight bump around 30 hz, but nothing major. That would work well then?
Reason for wanting the volume is to be able to fit a large enough reflex-tube. With WINisd's desired volume the tube's length would be greater than the height og the tube.
With 60 litres and 25 hz tuning the graph show a slight bump around 30 hz, but nothing major. That would work well then?
Reason for wanting the volume is to be able to fit a large enough reflex-tube. With WINisd's desired volume the tube's length would be greater than the height og the tube.
Yeah, sometimes you get some outlandish vent sizes!! You wind up scratching your head, saying, my box won't be big enough for that vent!!
I tend to trust our programs these days, it's all in the math & I don't argue with my calculator, so...
Your bump you probably won't even notice as room interaction "adds" ...or subtracts, from your eventual "by the time it gets to my ear" performance.
The WinISD I use doesn't have a Qts value for a ported alignment. I would assume their volumes & tunings are "set" for 0.707 ....& when we tweak these values, the resultant Q goes south.
----------------------------------------------------------Rick............
I tend to trust our programs these days, it's all in the math & I don't argue with my calculator, so...
Your bump you probably won't even notice as room interaction "adds" ...or subtracts, from your eventual "by the time it gets to my ear" performance.
The WinISD I use doesn't have a Qts value for a ported alignment. I would assume their volumes & tunings are "set" for 0.707 ....& when we tweak these values, the resultant Q goes south.
----------------------------------------------------------Rick............
Last edited:
A lot depends on how long the sonotube is and whether or not the vent will be at the top or down on the driver baffle. If the latter, then going a lot larger [> Vas] than WinISD calculates is not a good plan unless you tune the pipe lower, preferably to Fs, and damp the vent to keep it from potentially audibly 'ringing' on low notes.
If the pipe is going to be > 4 ft long and preferably around 6 ft, then a much larger volume [net Vb] can be used since it's 1/4 WL pipe action will damp the vent and'pump up' the low end somewhat with a Fs or maybe even a little lower tuning.
If it's a long sonotube pipe, then ~0.18" [3/16"] is thick enough that when properly constructed will need no bracing, though if a short, large diameter tube [< ~ 2 ft] is used to make a 'low boy', then some bracing may be required.
GM
Try with 8 or 8.5 cm tube (paper tube from carpet rolls). Is the length OK now?
Efficiency Bandwidth Product comes in at 66.66 tending, but not solidly into the ported camp....Most figure the breakpoint at 50.
Another take might be to locate the port(s) along the body of the cylinder, rather at either end...Perhaps a quad of 80mm???
To mix things up, trying not to "pile-up" resonances, I would locate them 5/8ths the length down...trying not to do even distances, almost a random value..
--------------------------------------------------------------Rick..........
Another take might be to locate the port(s) along the body of the cylinder, rather at either end...Perhaps a quad of 80mm???
To mix things up, trying not to "pile-up" resonances, I would locate them 5/8ths the length down...trying not to do even distances, almost a random value..
--------------------------------------------------------------Rick..........
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.