HI
Tuned to 21 Hz
Not stuffed just felt on panels and baf waddling in base of cabinet.
Port is flared both ends and has a 90 degree bend.
Tuned to 21 Hz
Not stuffed just felt on panels and baf waddling in base of cabinet.
Port is flared both ends and has a 90 degree bend.
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Not sure if you have tried modeling your speaker but here are some interesting stuff about what you are doing. Based on this. You can try it, very easy to use because the speaker is already in the database.
Speakerbuilder Pro 2.0
1) Your port will be about 2 feet long. Might a challenge to fit inside your box. Nobody sells a 2 foot port. So will need to link a PVC pipe to a flared port. Also might be a bit tough to fit your box. The ideal size is closer to 80 litres. So your box is kinda small.
Change your tuning to 30Hz and you will get a slight bass boost at about 40 to 50 Hz, and could potentially sound quite nice. Port will be about 30cm.
2) If you were to do it sealed. The frequency response would be the same as ported at 21Hz and yet your system will not run out of excursion because if the incredible x-max of 11mm.
Oon
Here are a couple of winisd sims in 40litres, both vented and sealed. Looks good enough to proceed in my opinion.
40L sealed is pretty close to ideal with a Qtc~ .66, f3~ 42hz and a nice shallow roll off.
40L ported is a bit undersized but does lower the f3 to ~31hz with a steeper roll off.
40L sealed is pretty close to ideal with a Qtc~ .66, f3~ 42hz and a nice shallow roll off.
40L ported is a bit undersized but does lower the f3 to ~31hz with a steeper roll off.
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In HR, the vent is 59.2 cm/23.3" long tuned to 21 Hz with a ~36 m/s vent mach/200 W, ~27 m/s 100 w, ~21 m/s 50 W with ~17 m/s the accepted max, so you tell me. 😉
I doubt that it will ever be 50 watts and the speakers are bass units in 3 way boxes for music only. At 20 watts and 30 hz the velocity is 5M/sec wich is fine.
I would move the tuning up to 24hz or so, but it's good to adjust tuning to taste after the fact anyway, just don't make the port permanent until you've experimented.
I think you might be missing the point. Designing the speaker is about choosing the compromises you want. For bass reflex, it will improve the bass response and increase the power handling if properly designed. However you box will be bigger. For sealed, you will have less power handling and generally poorer response but the upside is the box will be smaller.
So the problem now is the box is too small and the vent diameter too small you will not achieve the 2 benefits of BR and you might be better off sealed. The port is now crippling the speaker. Based on simulation, your speaker will be giving puffing sound at about 20-50W. But if you run it sealed, your woofer can run to over 100W without any issue because of 10mm Xmax. If you are going to run 20-50W only a 8 inch speaker might actually give you better bass performance than a 10 inch speaker in a 40liter cabinet. Have to sim to find out. In addition a sealed speaker actually has better transient performance.
If your speaker had only say 5mm of xmax, I might have suggested port to increase power handling but 10mm xmax, your woofer will probably be louder sealed than it would be ported.
Now that I figured out this speaker has 10mm of x-max, I would love to try it out myself one day. I didn't realise it has that much xmax. I thought it would have only be 5-6mm only.
OK, scanning the thread I see no power limit to account for, so for the record in case others should be interested, your alignment can use all 200 W down around tuning in 2pi space, so even a bit higher up if up against a wall and of course considerably higher if corner loaded.
I think it seems that the best idea is that I build it ported and if I don't like the result stuff the port or remove it and blank off the opening.
+1 and believe the 'critically' damped [click test] or stuffed to 'taste' [~aperiodic] is where the best [trade-off] of both type alignments lies for most folks [me included].
...*might* be to yes use an 8" driver instead, more suited to porting in that size. And "under-tune" the port lower, even Richard Small agreed with me F3 is not very meaningful, F6 or F10 are more important due to room gain.
Don't build a 10" with a tiny port-once upon a time I made some designs for new woofers my employer was selling. My coworkers built one such 10" box, complained it sounded like sh!t. Hmmm. Small port almost hitting the back of the enclosure, D'OH! Silly fools...I did when a neophyte build some 2? cubic foot Peerless 8" for a friend, 2" or maybe 2.5 ports, not big enough as he loved to blow out candles with them at parties. (Sounded OK though).
Now myself, I love cone area, I'd probably try to do a low-tuned shelf port. If I needed more length, maybe the entire back wall of the enclosure, with a wraparound big dowel for radius inside and if possible on the outside. Heh if you did that right you could scoop out the dowels to make handles for carrying!
Good idea. You can compare the difference in sound. If possible, if it is still there you can buy the port from part express which is telescopic. You can put it outside, port doesn't have to be inside. Adjust to taste and compare.
To be fair to you, by the time a 3"port start chuffing, your wife would not be very happy about that .... the bass will be plenty loud.. the only problem is how to build a port that long. People also tend to avoid long ports as it will act like a transmission line and you will have a resonant frequency. The lower the resonant frequency the harder it is for the cabinet to absorb it before going to the port.
Oon
Ah by which I meant I'd probably still be trying to accommodate the 10"woofer. One thing, if you tune low, the air velocity may reduce, though you really have to simulate and see.
And why I've been using/promoting morphing the box + large/long vent net volume [Vb] into an inverse TQWT ever since high power, low Fs, Vas drivers became available and damp to 'taste' 😉.
I cannot understand why anybody would tune a 40litre cabinet with a 10" woofer to 21Hz. In simple terms: a port offers a 3dB increase around the tuning frequency by utilising the output from the rear of the woofer. At 21Hz you are attempting to add 3dB to 'nothing'.
If you reverse engineer a commercial subwoofer with 10" driver you'll find the ports are tuned above 35hz.
If you reverse engineer a commercial subwoofer with 10" driver you'll find the ports are tuned above 35hz.
Things may have become a little complicated.
The design I was looking at uses an LCR circuit on the midrange unit and on the bass unit due to a low point of crossover and I have been told that if I change the bass tuning ie box size and port tuning that the LCR circuit would have to be changed also.
I dont know much about that sort of thing and although I can see that it may change the LCR circuit on the bass unit I assume the mid circuit would stay the same.
Also if I were to build it sealed I assume that the LCR would still need to be changed or am I wrong.
The design I was looking at uses an LCR circuit on the midrange unit and on the bass unit due to a low point of crossover and I have been told that if I change the bass tuning ie box size and port tuning that the LCR circuit would have to be changed also.
I dont know much about that sort of thing and although I can see that it may change the LCR circuit on the bass unit I assume the mid circuit would stay the same.
Also if I were to build it sealed I assume that the LCR would still need to be changed or am I wrong.