Not sure about the Acoust-X. I guess that would be a rather thin layer of material, so sound absorption wouldn't be much.
You'll need something a bit thicker than just "a bit of paint". Good old open-cell "egg foam" or thick felt (at least 1cm thick, but more would be better) works well. Wool is often used to stuff sealed enclosures. It is not so much used with bass reflex systems, where you want an unstuffed air volume, at least between the woofer and the port. I recently also came across "Basotect", and I tried it in the Monkey Coffin. Works well!
I'd suggest to build the box without any stuffing at all, and do some measurements first (impedance, acoustic) to see what you get. Then try adding different amounts and types of damping to treat the internal modes/resonances.
I prefer doing initial measurements without any damping at all, because that shows very clearly where the potentially problematic resonances are. Comparing measurements with/without damping may also very useful to understand what's going on in a speaker system.
that Basotect stuff is pretty expensive.
I found some for a good price on ePay. Also take a look here.
Hi mbrennwa
Yeah it has been a while, Life is happening and a lot have changed at my end, long story short, we moved to a new location and two 250L monstrosity would be a very tight fit for the living room, with just a foot or less away from the walls and each corners, and most important it will not be approved after the wife realizes the actual size of the speakers !
The reason I haven't brought this up before is that I wanted to find a solution before start tossing ideas around again, or me having to abandon the project.
The only option for me would be to reduce the foot print, making the front as narrow as possible (with about 15mm or less from the woofer edges to the sides) which I m not sure if it introduce new issues, also the height is limited to 47" (119cm) due to available sheet size of 48" and my limited tools and woodworking skills, so this will reduce the cabinet volume to original 150 liters we had in mind, which is not bad and I don't see any other way that I can make it work.
option number two is to sell the drivers and start over.
thoughts?
I've got Faital 15fh520 + 8pr155 + hf10ak with STH100 horn in prototype stage, but its a slow progress. I'm not sure yet if its gonna be fully active or have a passive crossover between mid and tweeter. Also, it is around 100 litres for the woofer currently. I'll post the end result here when when ready or abandoned My gripe at the moment is that the 15fh520 woofers I have don't measure even close to the spec. Need to exercise them many hours and see if the parameters have changed. If not, this is not a good woofer for a fullrange speaker. Kicks well with subs handling the lows though, and then can be used in much smaller sealed enclosure.
My gripe at the moment is that the 15fh520 woofers I have don't measure even close to the spec. Need to exercise them many hours and see if the parameters have changed. If not, this is not a good woofer for a fullrange speaker. Kicks well with subs handling the lows though, and then can be used in much smaller sealed enclosure.
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I have thought about a sealed box and to use a sub (or subs) to cover the lower octaves, the AE TD15Xs need a 94 liter box for a q of 0.7 and it will go to around 60Hz for f3, 94 liter+bracing+other drivers wouldn't be much smaller than original 150 Liter in mind and it still need another set of driver(s) and amp and DSP to run the subs, so yeah, not convenient, with a net volume of 150 liter bass reflex box tuned at 30, the TD15Xs can breath a little & can go down to 37Hz and hopefully to 30Hz with some EQ which will make me happy, unless my cals are wrong.
I m not sure if anybody still following this but let me know if you are still interested in the project and what do you think of the changes.
If i don't see much interests I may take a different approach.
I m not sure if anybody still following this but let me know if you are still interested in the project and what do you think of the changes.
If i don't see much interests I may take a different approach.
This is not what the poll and the design goals were about -- but I like your idea. With a strong amplifier, you could also use a Linkwitz-EQ (active) to make the sealed box go lower.
Not completely clear for me, so the plan is to place the AE TD15X in a 94 L sealed box, and add subs later with extra transducers for more low frequency extension.
Also possible in a first concept to add active low frequency equalization to the TD15X in 94L with a Linkwitz transform, like Matthias is mentioning also.
Also possible in a first concept to add active low frequency equalization to the TD15X in 94L with a Linkwitz transform, like Matthias is mentioning also.
Sorry if I was not clear, I was talking about the sealed option because it was mentioned in previous post.
What I was trying to say was that sealed option is not ideal here because of the reasons I mentioned.
Right now i m looking at a 150L net volume bass reflex box, if I remember correctly the original design for TD15Xs was 150L also before we decided to go with 240L "Extended Bass" version.
let me know what do you think of 150 liter bass reflex box, nothing else is changed.
So far I have participated in this project, same as the rest of you, but due to my new limited space I simply don't have enough room for two 240L titans, I would be happy if someone can take over and continue the project as it was planned, supposing we still have people interested, but if no one else is willing to take over the build, I m willing to go with a smaller 150L bass reflex.
I’m probably being «Captain Obvious» here, but I just want to point out that while the Linkwitz transform will allow you to get much more extension (lower f3) from a limited volume, the absolute limits for Xmech will remain the same. The max xpl at higher frequencies will decrease for the same music content (because Xmech will be reached sooner).
That said - I use Linkwitz transforms both on the mid and woofers, before doing other eq and xo. I like to straighten the curves a good bit beyond the xo frequency.
Johan-Kr
That said - I use Linkwitz transforms both on the mid and woofers, before doing other eq and xo. I like to straighten the curves a good bit beyond the xo frequency.
Johan-Kr
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