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Get familiar with the reaction system: Introducing the Reaction System
Infinity IMG 8" woofers
I just bought 4 of these and will have to refoam 3 of them. The one that seems ok I ran T/S parameters on. Through them into WinISD and the results seemed quite a bit off from what I was thinking.
Can someone run the numbers in their software ( maybe not WinISD) for two of them in a closed box.
Re 3.728
Fs 38 hz
Qts .81
Qes .96
Qms 5.17
Le .37
Mms 19.3
Vas 2.076 cubic feet
SPL 91 db 2.83 volt
Comments
Just so you know, WinISD came up with a 21 cubic foot box!
Also, is there an easy way to figure out XMAX? I just put 4.5 mm in. Guessing.
Qts of .8 with a Vas of 2cf... yeah it will "want" a big box. What was the box Q at that size?
I think there is a way to guestimate xmax.. Though I think it entails measuring xmec and calculating a % of that.
Rum em sealed
Qb was .9, lol! I just simmed the RS6001 and it has a gross internal volume of 1.64 cubic feet. I put 1.5 cf in and it shows 35 hz -12 db. Funny enough, Infinity advertises frequency range of 35-hz - I think 44khz . The model has a peak at 85 hz of 3.75 db. - 3db at 53 hz. Were they really like that? From what I remember they sounded pretty good to me at 20 years old.
Oh, and box Q is 1.45 on this sim.
Yeah I was asuming that was a sealed alignment, but maybe not if it is suggesting that big of a box.
Yeah, I could understand maybe 4 or 5 cf, which would be too big but 21?
Anyway, I may build a test box at 1.64 cf gross and see how it measures and sounds. I was hoping for more extention and less of a peak. I tried 2, 2.5 and 3 cf. 3 cf seemed good to me but man, that is a big box.
Great brew BTW!
Stuff the crap out of it, and port low.
InDIYana Event Website
Or aperiodic sealed.
InDIYana Event Website
That's what I was thinking
I thought about just stuffing the hell out of it. Tjat might help some. All I can do is try it out.
I don't know anything about designing one of those. I have heard about them for years but....
It's worked for me before....
InDIYana Event Website
I was looking to do something like this.
That IS sealed! I would never try to run woofer with a Q of .8 in a ported box!
Some how I missed this post. In my original post I did say two of these in a closed box/ sealed.
My win-isd calculated a 10ish cf sealed box for a Q of .9 with your parameters.
It doesn't look too bad for a 2cf sealed enclosure (pictured below). I added .5ohm series resistance for XO parts, which boosts the peak a bit. Thats only 2.5db empty. full stuffing can squash it back down a bit. I know you are probably leery about such peaks due to your recent experience. But nearly 40hz f3 is pretty nice for sealed alignment.
1.6cf only boosts the peak about a quarter db and raises f3 a couple db. Not much difference. Stuffing it should help. If you have access to free fiberglass insulation that seems to work ever so slightly better than polyfill. Even with a peak it should sound less muddy than a vented/PR enclosure.
I think that Vance D. explains it as just a different way of introducing damping, not much different than stuffing the crap out of it. But it seems to me that the flow resistive vent to the outside would make the enclosure appear acoustically larger.
That looks better than what I got, even when I added full stuffing. Thanks for running the sim. I think I just have to build a test box and see what I get. If I am not happy I will just sell them and use something else, more modern drivers. I was looking at maybe running two 12s instead of the 8s. Looking at two of the RSS315HO-44s. That would be a massive difference, I know, but I thought I would try these 8s out.
Just noticed. You used one driver. One would work great. But I was shooting for two. Maybe using only one might pan out. Don't know how loud they will go. Doesn't seem like they will take alot.
LOL everyone is posting so fast the forum is having a hard time keeping up. There were only 4 posts when I submitted my previous post.
Ok. yeah 2x makes sense for what you were seeing then.
Aperiodic is basically just a controlled air leak. I have contemplated making one with a couple small steel waffle grills sandwiching some foam or polyfill over a hole in the box. Could possibly adjust how much air resistance it has with more stuffing between and/or how tightly the sandwich is screwed down. It seems to work well for Ben with midranges. And I have read of others using it with good results for woofers. But it is just one of those fringe things that hasn't gotten a whole lot of mainstreem attention in the hobby in the past 20 years. I suppose because folks just opt to use lower qts drivers since that is a widely available choice nowadays.
I was thinking that and it makes sense. I just wasn't sure how to implement it. Is the box the same size for sealed or ported or something else? How big or long does the port have to be, etc.
Very interesting to me. Would like to try a build like that but I wouldn't know where to start.
Me too
Yeah, I think we need the " Infinity and Beyond" theme for next year! Your set looks better than mine at the moment, but I am weighing my options. I just thought maybe using some original drivers would be cool. Rock on, dude!
Hmm I do have a pair of PT2Cs and 4x mcm 55-5670s.. Just need to find some "boobs". No dangit stop or you gona pull me in too ehehe.
I built these years ago and they are my reference system. They are quad amped, DSP, etc. Still in test boxes, ugh. Two 8s. In room, - 3 db 18 hz. Stupid low distortion, yada yada....
Do it!!!
what drivers? and PR?
A couple of comments on "aperiodic" which was mentioned a few times above.
When Ben has talked about his ice-cream sandwich method, he is using a multichambered aperiodic sealed box - it is actually two sealed boxes with the divider causing an aperiodic effect between the two sealed boxes. But it is not leaking to the outside world. He does this to reduce the impedance peak.
A normal aperiodic box for the woofer brings down the "hump" in a "too-small-box", something like the Q=1.2 above. It is a resistant port between the sealed box and the outside world. You can model it in the Advanced Box Settings of WinISD by setting Ql to 3.
Bliesma T25b, Tang Band 50-1426, Purifi 6.5" midrange, two RSS210-8 AND 12" DSA PRs per side. Crossed over at 200 hz, 1khz, 4khz. Using Adcom, and Parasound amps.
If ya squint hard enough, both are a leaky enclosure spilling into another space. Technically yes-different, since one space shares the same space as the front of the cone while the other does not. Both would seem to achieve a similar effect of taming an otherwise excitable bottom end for the driver. But maybe I'm just oversimplifiying and mowing down the important details