band pass sub

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   These kinda boxes are interesting and kinda mystery. To me anyway!

Good work! 

Hope to see some video or something about this!

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app Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 26 December 2013 Location: Finland Status: Offline Points: 2435	Post Options Post Reply Quote app Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 12:06am
	These kinda boxes are interesting and kinda mystery. To me anyway! Good work! Hope to see some video or something about this!
	"what!?"

mini-mad Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 13 July 2012 Location: london Status: Offline Points: 6903	Post Options Post Reply Quote mini-mad Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 1:15am
	Me too.... iv been after a 15 inch band pass for A LONG TIME!
	If it sounds like a gorilla is trying to escape, turn it down.

b grade Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 05 October 2012 Location: Portland OR USA Status: Offline Points: 1337	Post Options Post Reply Quote b grade Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 1:50am


b grade Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 05 October 2012 Location: Portland OR USA Status: Offline Points: 1337	Post Options Post Reply Quote b grade Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 1:54am
	I can't say for sure that I hit my target, but it sounds really nice at the levels I can get away with at home. I will see about measuring to the best of my ability, but I am not in any real hurry. Ear test approved anyhow. If I do not change my mind about it, I will paint it up in a couple days.

studio45 Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3864	Post Options Post Reply Quote studio45 Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 4:17pm
	I'd like to turn you on to this little utility, if you haven't seen it already: http://www.subwoofer-builder.com/flare-it.htm It's very useful for telling you whether your ports will be noise-free. Those seem quite narrow to me - as you've said you haven't been able to test it at full power yet, I would be interested to know if the ports can cope with the driver's full output.
	Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA

MarjanM Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 10 February 2005 Location: Macedonia Status: Offline Points: 7816	Post Options Post Reply Quote MarjanM Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 4:21pm
	What are those cavities on the sides?
	Marjan Milosevic MM-Acoustics www.mm-acoustics.com https://www.facebook.com/pages/MM-Acoustics/608901282527713

t.geessounds Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 10 May 2010 Location: US... New york Status: Offline Points: 908	Post Options Post Reply Quote t.geessounds Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 5:25pm
	i guess handles

b grade Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 05 October 2012 Location: Portland OR USA Status: Offline Points: 1337	Post Options Post Reply Quote b grade Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 5:48pm
	Yes it is a handle that goes all the way across the sides. They are big but they allow you to grab it wherever it works when trying to wrestle it into the van. Also, going all the way accross they are failrly effective braces, especially when attached to the perpendicular brace that goes all the way accross and attaches the two handle boxes together. The volume displacement was considered in the design. As for the vents, I did flare them slightly on both sides, but my simulations have these at very low vent velocities because there are 12 per chamber. The area of vent per chamber is 204cm^2. I get mach 0.02 from the front calculation and 0.01 from the rear so I think it will work ok even at high power. We shall see I suppose. I have a gig to test it at next week. I believe a single sub will be totally underwhelming with the rest of the system, but I can run it to full power and make sure it does not whistle or self destruct under pressure. I was surprised that I could work with a vent that small, but it is not a particularly high xmax driver. I can say for sure that when I listen to it, it does not seem to lobe between chambers at low power. A sim curve for frequency response for a BP6 kind of looks like a tapped horn with an upper lobe and a lower lobe and hopefully you can try to get the middle part within a db or so. The first one I designed, I made the upper lobe even with the middle and the lower lobe up about 1.5dbs. It worked, but you definitely can tell which vent you are listening to at any given moment. That lower one comes on and just crushes. For this one I tried to get a flatter sub response, and the result sounds more natural I think. totally subjective ear observations: For casual listening the reflex mode sounds best. For a great need of efficient sub, the BP6 has all the advantages. Edited by b grade - 05 June 2015 at 6:07pm

b grade Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 05 October 2012 Location: Portland OR USA Status: Offline Points: 1337	Post Options Post Reply Quote b grade Report Post Thanks(0) Quote Reply Posted: 05 June 2015 at 10:36pm
	I measured to the best of my ability in my very non ideal setting and it looks about how I want it for the range I want it. There is an ugly spike in efficiency at 100hz, but that is way higher than I would run in band pass mode, and also, that may just be a resonance of the room. I ran it as loud as I can in the house without bringing the police, and there was no port noise. Its like a fan in front of it though, and the frequencies I am running shake the framing of my house so some port noise may be hiding in there. So far I haven't detected any. So this is my unscientific measurement with only a 30 hz hpf This is the bit I intend to use as a bottom with my 1850s HPF at 30hz and LPF at 56hz. Edited by b grade - 05 June 2015 at 10:37pm

b grade Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 05 October 2012 Location: Portland OR USA Status: Offline Points: 1337	Post Options Post Reply Quote b grade Report Post Thanks(0) Quote Reply Posted: 06 June 2015 at 7:42pm
	I have been trying to run at louder levels in short bursts at my house, so I can try to hear problems, but not get a police fine. At first I thought I was getting port noise but the access panel was not as tight as it could go. Once I tightened it, it no longer made that noise. I may need some bracing on the access panel itself though. Being such a big panel, it could use a little beefing up. Also, when it gets near xmax, the wind in front increases dramatically. Since you can not really hear a driver struggling in a BP6, I may have to use the air movement to be the indicator of the driver being over driven. Comfortable breeze, a-ok. Hurricane gale, ease back a bit buddy. My sims indicated that it could take 800 watts before xmax, but in reality it seems that 500 watts is plenty enough to drive it pretty hard. Then again, I am in a confined and rattley basement, so I may find that to not be the case when I take it into battle.

njw Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 26 March 2010 Location: S. Wales Status: Offline Points: 2574	Post Options Post Reply Quote njw Report Post Thanks(0) Quote Reply Posted: 06 June 2015 at 10:03pm
	That looks sweet, the quality of some 'diy' builds on here is astounding. Edited by njw - 06 June 2015 at 10:07pm

b grade Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 05 October 2012 Location: Portland OR USA Status: Offline Points: 1337	Post Options Post Reply Quote b grade Report Post Thanks(0) Quote Reply Posted: 06 June 2015 at 10:50pm
	I sincerely appreciate the compliment. It is a labor of love. And also anxiety and consequential poverty. but mostly just love.