I think I'm going to go for a number of B2500.1 in TL boxes for my next HT sub.
I've got one at the moment and it sounds good but not very loud.
I've got one at the moment and it sounds good but not very loud.
BlackCatSound said:
I used the B2500.1 quite awhile ago. Nice sound, I'm sure multiple TL's will sound the business.
richie00boy said:
Mostly correct. The probem here is that volume of air in the cabinet naturally couples to the interior walls. HOWEVER, there are plenty of dampening materials that have fairly low friction surfaces while still providing good vibration-to-heat conversion. (I.E. look to the adhesive/aluminum backed pads that the car industry uses - with these the aluminum surface is low friction.)
Those pads are just mass damping designed for thin metal car panels, not thick MDF.
edit: Expletive removed.
edit: Expletive removed.
ShinOBIWAN said:
Yup, the design "as is" will do *most* movie tracks - BUT when you have any material more than a few Hz below the tuning freq. you are in serious trouble.
You'll have multiple problems with tunning much below 19 Hz.
1. Efficiency drops significantly.
2. Power compression becomes a serious problem at even lower volume (spl) levels.
3. The vent size becomes overly large and cumbersome to integrate.
Of course you can get "around" #3 by using a passive radiator - BUT a passive radiator IS not as good "musically speaking" as a vent. (..and the reason is linear rise-time and decay in the region where the design should linear.)
BlackCatSound said:
True.. But that doesn't mean they don't provide benefit. I.E. they still work, but they are not as effective.
Bitumen sheet is of limited use in the thicknesses its normally supplied in.
I used a 8mm on the walls of the Perceives as recommended by the study done by Rogers/BBC years ago now. Anything less is practically just wasted volume.
I also believe in that the so called cure is worse than the problem half the time. I removed most of the stuffing out of the bass section of the Perceives after listening tests. With it, it was slightly smeared.
The sub cabinet is more than robust enough to fully get away with losing these mostly harmful trimmings. Get the construction right and you don't really need that stuff.
I used a 8mm on the walls of the Perceives as recommended by the study done by Rogers/BBC years ago now. Anything less is practically just wasted volume.
I also believe in that the so called cure is worse than the problem half the time. I removed most of the stuffing out of the bass section of the Perceives after listening tests. With it, it was slightly smeared.
The sub cabinet is more than robust enough to fully get away with losing these mostly harmful trimmings. Get the construction right and you don't really need that stuff.
BlackCatSound, please refrain from using expletives.
For the HT crowd:
http://www.tcsounds.com/forums/index.php?showtopic=172
I'm betting that would satisfy my need to feel what its like when a handgrenade goes off in the same room as yourself.
http://www.tcsounds.com/forums/index.php?showtopic=172
I'm betting that would satisfy my need to feel what its like when a handgrenade goes off in the same room as yourself.
The TC isn't much lower in freq. than yours, and is a bass reflex.. BUT the drivers can handle a LOT more excursion and may not "bottom-out" to the same extent when pushed below the port tunning (depening on SPL of course). Still once you go much past 3 Hz or so below the tunning the response drops like a rock - so even here the TC design may not have enough extension.
Just thinking about this..
You know.. I've searched for commercial subs that do *tough* HT - i.e. freq.s extending to 10 Hz relativly cleanly (..and perhapse even as low as 7 Hz).
Long story short: couldn't find ANY. (..neither ELF's nor rotary based systems are what I would characterize as "clean".)
Heck, even the new uber expensive Velodyne is not designed to go much past 15 Hz.
The sad thing is - its HIGHLY unlikely that even very good theaters provide extension lower than 15 Hz. MOST of the good ones (in the US anyway) use JBL that is a bass reflex design - so they have the same problems.
Hmmmm... Perhaps its time to design one? 🙂
Just thinking about this..
You know.. I've searched for commercial subs that do *tough* HT - i.e. freq.s extending to 10 Hz relativly cleanly (..and perhapse even as low as 7 Hz).
Long story short: couldn't find ANY. (..neither ELF's nor rotary based systems are what I would characterize as "clean".)
Heck, even the new uber expensive Velodyne is not designed to go much past 15 Hz.
The sad thing is - its HIGHLY unlikely that even very good theaters provide extension lower than 15 Hz. MOST of the good ones (in the US anyway) use JBL that is a bass reflex design - so they have the same problems.
Hmmmm... Perhaps its time to design one? 🙂
Hi Scott,
TBH I'm real happy with the performance of the sub. I'm fully prepared to sacrifice the HT side of thing for the sheer snap and top to bottom realism that music now has.
The sub has cemented something I've been feeling for a while now and I've decide to ditch the 5.1 setup altogether and just go with a stereo setup + 2 subs whilst still keeping the projector for the odd movie. TBH I've not been watching much in the last few months anyway. I do find myself listening to music every day though.
Because of the HT thing I painted the entire room in dark/medium grey tones to combat scattered light from the screen. The room is therefor very dark even in the day with light comming in from the window. Every wall in the room is also plastered in dark grey acoustic tiles - its actually a little disorientating when you enter the room after comming from another part of the house because there's a distinct lack of air and feeling to the acoustic of the room. Overall the whole thing slightly depressing if you spend a deal of time in there.
In light of the emphasis on 2 channel and the need for a more upbeat room, I'm gutting the whole thing and going for a minimalist, bright and slightly modern look. I don't want obvious acoustic treatments this time and really like the look of Ralphs excellent Aeropanels:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=84334
And these:
So will likely go in that direction. I'm thinking about using some 3mm bendy ply and trying to do a gently curved panel for the ceiling beween the speakers and listening position.
All this means I've now taken the system apart. Bit gutted because I'd just started to be feel the system was now complete. However its also a great excuse to spray the sub and I've also got the chance to finally do the baffle on the Perceives in concrete, so they're back in bits again 🙂 I was surprised at just how much dust they were covered in once I'd put them somewhere bright, its so dark in that room I never even realised - a good thing by the looks of it:
TBH I'm real happy with the performance of the sub. I'm fully prepared to sacrifice the HT side of thing for the sheer snap and top to bottom realism that music now has.
The sub has cemented something I've been feeling for a while now and I've decide to ditch the 5.1 setup altogether and just go with a stereo setup + 2 subs whilst still keeping the projector for the odd movie. TBH I've not been watching much in the last few months anyway. I do find myself listening to music every day though.
Because of the HT thing I painted the entire room in dark/medium grey tones to combat scattered light from the screen. The room is therefor very dark even in the day with light comming in from the window. Every wall in the room is also plastered in dark grey acoustic tiles - its actually a little disorientating when you enter the room after comming from another part of the house because there's a distinct lack of air and feeling to the acoustic of the room. Overall the whole thing slightly depressing if you spend a deal of time in there.
In light of the emphasis on 2 channel and the need for a more upbeat room, I'm gutting the whole thing and going for a minimalist, bright and slightly modern look. I don't want obvious acoustic treatments this time and really like the look of Ralphs excellent Aeropanels:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=84334
And these:
An externally hosted image should be here but it was not working when we last tested it.
So will likely go in that direction. I'm thinking about using some 3mm bendy ply and trying to do a gently curved panel for the ceiling beween the speakers and listening position.
All this means I've now taken the system apart. Bit gutted because I'd just started to be feel the system was now complete. However its also a great excuse to spray the sub and I've also got the chance to finally do the baffle on the Perceives in concrete, so they're back in bits again 🙂 I was surprised at just how much dust they were covered in once I'd put them somewhere bright, its so dark in that room I never even realised - a good thing by the looks of it:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Defitinitely know what you mean regarding HT and 5.1 versus just focusing on solid 2 channel audio. I have a nice DLP projector set up with a decent stereo system and sub, my family and the occasional visitor never seem to care about the lack of 5.1 sound and instead focus on the beatiful picture and music the system is capable of. I am sure many will disagree and have also accomplished some spectacular 5.1 systems, but for me and my family the added cost and complexity just isn't worth it, and even more importantly I think it just makes throwing down some music while we read or talk or whatever so convenient and compelling that we do it more often. Experiencing the sheer joy of the worlds music is what got me into this hobby in the first place.
Regarding the sub design, have any of you guys looked at these commercial designs and attempted to think through if there is something of merit here or not. The first one is Zu Cable's Definition, which seems to follow the "keep cone resonance above pass band" philosophy for there integrated subwoofer, though the use a small sealed chamber for all 4 of those Eminence drivers...
http://www.6moons.com/audioreviews/zu2/definition.html
The second one that I find even more interesting is the Escalante, which uses compound loading and staggered crossover points, low passing the rear (internal to the cabinet) driver around 80hz and then letting the front driver run well up into the midrange... and claiming that this creates an environment for the front driver to have a controlled resonance of sorts and thus lower distortion and dramatically improve the rise time of the drivers response:
http://www.positive-feedback.com/Issue26/escalante_fremont.htm
I normally don't pay much attention to the HiFi press or commercial markets as I am slowly moving towards a mostly DIY system, but these two systems really got my curiousity up and the reviews are both a fun read.
So the last one got me thinking, instead of taking on the whole mid dome instead of whizzer engineering for super extended range from the woofer, is it possible to take the framework of Scott's design, and compound load a second B&C 12TBX100 in front of it and run it all the way up to 90hz or even up to 3-600Hz depending on your overall system design goals and the other drivers involved. Thinking about Scotts take on the frequency ranges that constitute hall valume, slam, punch, etc... wouldn't it be nice to have a stereo pair of bass towers that cover it all before handing off to an upper-bass/lower-mid driver in another cabinet that starts the final stage of the journey to a full range system. Of course, that's if there is something to Tierry's patents worth cloning (for our own, non-commercial use of course).
Anyways, these two products and their accompaning reviews/descriptions/patents go into territory I have not seen discussed on the various diy forums before, most of the time these things are a big yawn for me and I much prefer the forums, these two struck as worth looking at as closely as possible.
http://www.6moons.com/audioreviews/zu2/definition.html
The second one that I find even more interesting is the Escalante, which uses compound loading and staggered crossover points, low passing the rear (internal to the cabinet) driver around 80hz and then letting the front driver run well up into the midrange... and claiming that this creates an environment for the front driver to have a controlled resonance of sorts and thus lower distortion and dramatically improve the rise time of the drivers response:
http://www.positive-feedback.com/Issue26/escalante_fremont.htm
I normally don't pay much attention to the HiFi press or commercial markets as I am slowly moving towards a mostly DIY system, but these two systems really got my curiousity up and the reviews are both a fun read.
So the last one got me thinking, instead of taking on the whole mid dome instead of whizzer engineering for super extended range from the woofer, is it possible to take the framework of Scott's design, and compound load a second B&C 12TBX100 in front of it and run it all the way up to 90hz or even up to 3-600Hz depending on your overall system design goals and the other drivers involved. Thinking about Scotts take on the frequency ranges that constitute hall valume, slam, punch, etc... wouldn't it be nice to have a stereo pair of bass towers that cover it all before handing off to an upper-bass/lower-mid driver in another cabinet that starts the final stage of the journey to a full range system. Of course, that's if there is something to Tierry's patents worth cloning (for our own, non-commercial use of course).
Anyways, these two products and their accompaning reviews/descriptions/patents go into territory I have not seen discussed on the various diy forums before, most of the time these things are a big yawn for me and I much prefer the forums, these two struck as worth looking at as closely as possible.
Baffles out of concrete... hmm... Could you explain the reasoning behind this? Would it not be better/easier to make them out of aluminum, or if you want them really tough, steel? Is there a resource somewhere that I could read that would explain to me what properties are important for loudspeaker enclosure material, the effectiveness of different materials (ie. steel, aluminum, concrete, MDF, etc), and which portions of the enclosure (baffle, backwall, sides) need which kinds of materials?
m0tion said:
Hi motion, good to see you again.
From looking more closely at this problem, it appears that concrete mixed with leadshot offers a great deal in terms of damping material resonances - possibly one of the best aside from expensive composites and polymers.
I had a great link in my bookmarks awhile a go which referenced accelerometer tests of various material including concrete, MDF, ply and host of others. Unfortunately I formatted the computer not long back and I've lost the link. I believe the measurements were performed by a member here too.
ShinOBIWAN said:
I know exactly how you feel. No sooner was I completely happy with my active PMC rig than I sold the speakers, pre-amp and amps and started building my own entire system apart from the transport! The truth is I suppose, you have to do that when you get to the limits of the system as it is, and it needs a complete re-form to go further.
If I am not mistaken, that is Robert Miles' studio isn't it? I have seen pictures of it before I think. I also know a guy who had his place designed by audio-architecture and I may be recording there in the next month or so.
ShinOBIWAN said:
Sounds like a good idea to me! (..and I like the esthetic - looks like you are looking for something a bit more "mature" this time around.)
I've actually never thought the two "mediums" were really compatable. This is mostly due to depth of imaging in a good 2 channel system which doesn't seem to "track" the on-screen 2-D image. (..though this might be different IF someone would bring back enhanced image depth for viewing. ..NOT the 3-D stuff which trys to have images that move forward of the screen and virtually always gives the viewer a headache.)
Moreover a decent HT setup can be made or purchased that works very well with HT at a very low price. Another nice thing here is that it can be built into the walls of a room without significantly detracting from either its ability, OR general decore.
Still.. none of thats to say that you can't use a 2 channel set-up for HT. It will of course enhance viewing to some extent while detracting as I mentioned above.
Scott:
Care to comment on my materials question a few posts up? I'd be curious to hear your input.
Care to comment on my materials question a few posts up? I'd be curious to hear your input.
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