You know I've tried to suggest most of this before.. but it doesn't seem to get through.. (..even on this thread there are precious few posters.)
What I will say is this:
1. side-band decay above and below the fundamental of direct sound is important, but distortion levels can be quite high without a serious deficiency in sound quality. In otherwords a good fullrange loudspeaker should be sufficient.
2. in-direct hall-sound however needs both low harmonic distortion and an extremely extended response FLAT in-room.
a. the need for low distortion seems to stem from are inability to seperate distortion from what is essentially distortion (in-direct sound). This is in contrast to direct sound (like an insturment produces) where distortion subjectivly alters the character of the sound, without obfuscating its nature.
b. the need for an extremely extended respnse is a function of the room (real or virtual) in which the direct sound is recorded in. This is simply a matter of doing the "math" on the longest boundry dimension of the room. A 1 Hz wavelength is about 1125 in length - some venues like stadiums will most def. have this length, even large amplitheaters will support this wavelength.
3. the nice thing about all this is what Pan suggested.. that while the SYSTEM needs to be flat in-room, the actual spl of hallsound (and even most side-band direct sound) is well attenuated in comparison to the music's average spl.
4. the bad thing about all this is that "flat" extension is almost never found and that most designs using a passive radiator or port are simply not tuned low enough to have any useable low freq. extension. Additionally, most so-called subwoofers have their mechanical resonance providing in-band HIGH levels of distortion - including the Bag End. For instance the Bag End 21 inch driver typically has an in-box resoance around 70-80 Hz, the problem is that the lowpass cut-off is usually to high in freq. (and typically not as steep as it should be either). A low freq. "steep" cut-off would work well for low spl hall sound, BUT if the signal had any appreciable direct sound at or near reference level then that will likely be heavily distorted because of the excursion levels required by Bag End's design. The only way around this particular problem with this design is MANY multiples of subwoofers.
Said differently, getting both flat extension and low distortion is a TOUGH problem for domestic settings.. and other than my own ramblings and the rare mass applied IB (in attic or home exterior) eq.ed system, I haven't seen any designs that really address the problem (..and I'm not even sure what I've previously suggested does - even it is large for a domestic setting).
What I will say is this:
1. side-band decay above and below the fundamental of direct sound is important, but distortion levels can be quite high without a serious deficiency in sound quality. In otherwords a good fullrange loudspeaker should be sufficient.
2. in-direct hall-sound however needs both low harmonic distortion and an extremely extended response FLAT in-room.
a. the need for low distortion seems to stem from are inability to seperate distortion from what is essentially distortion (in-direct sound). This is in contrast to direct sound (like an insturment produces) where distortion subjectivly alters the character of the sound, without obfuscating its nature.
b. the need for an extremely extended respnse is a function of the room (real or virtual) in which the direct sound is recorded in. This is simply a matter of doing the "math" on the longest boundry dimension of the room. A 1 Hz wavelength is about 1125 in length - some venues like stadiums will most def. have this length, even large amplitheaters will support this wavelength.
3. the nice thing about all this is what Pan suggested.. that while the SYSTEM needs to be flat in-room, the actual spl of hallsound (and even most side-band direct sound) is well attenuated in comparison to the music's average spl.
4. the bad thing about all this is that "flat" extension is almost never found and that most designs using a passive radiator or port are simply not tuned low enough to have any useable low freq. extension. Additionally, most so-called subwoofers have their mechanical resonance providing in-band HIGH levels of distortion - including the Bag End. For instance the Bag End 21 inch driver typically has an in-box resoance around 70-80 Hz, the problem is that the lowpass cut-off is usually to high in freq. (and typically not as steep as it should be either). A low freq. "steep" cut-off would work well for low spl hall sound, BUT if the signal had any appreciable direct sound at or near reference level then that will likely be heavily distorted because of the excursion levels required by Bag End's design. The only way around this particular problem with this design is MANY multiples of subwoofers.
Said differently, getting both flat extension and low distortion is a TOUGH problem for domestic settings.. and other than my own ramblings and the rare mass applied IB (in attic or home exterior) eq.ed system, I haven't seen any designs that really address the problem (..and I'm not even sure what I've previously suggested does - even it is large for a domestic setting).
Well, there's the fan subwoofer now.
Problem is the 14000$ price, and the IB installation needed.
It's flat down to 1 Hz.
Problem is the 14000$ price, and the IB installation needed.
It's flat down to 1 Hz.
phn said:
Your system sounds like the kind that REL targetted its subwoofers at before dvd / doldy digital took off. Use a pair of decent sealed 10 / 12" drivers below the full range mains, hopefully the sealed alignment works with the room gain below the rooms lowest modes. I believe REL also used to recommend corner placement too.
Personally I'm using a pair of tempests (soon to be 4) below a pair of labhorns, crossed at 30Hz. The tempests are pretty flat 15 - 30 with no room mode problems, and are eq'd flat before crossing at 24dB/oct to the labs.
Anyone who says music has no sub 40 / 30 Hz content should take a look at my tempests when listening at 'proper' volumes. Yep they move plenty.
Rob.
simon5 said:
You don't need that..
If you have the attic space then simply get a low distortion good excursion/large sd driver and mass-load the diaphram to about 5 Hz (or less for the mechanical resonance). Then use a LR 4th order low pass around 30 Hz or less and eq. it flat. With all but a few recordings distortion should be low and extension should be good enough.
This will likely be unacceptable for Home Theater - where you would be better off with something that had less low freq. extension and higher excursion levels.
Seems like an expensive excursion getting into HiFi down to even 20 hz at high spls. My mains have one dayton rs 12" (+/-14mm xmax) each in a sealed box. If I put in a fake linkwitz transform with the Behringer DEQ, they are going up to a significant portion of their excursion limit at high spls. At that excursion level, I can hear motor noise, (of course, I have an open layout, so maybe others will have more success). Maybe one day I will double up like Rob.
To get much more, I would need to pony up even more money for a high excursion adire or ascendent audio woofer in a LT'ed sealed box, or sacrifice my relationship with my gf and build some huge vented contraption.
As an aside, I don't even think I get the LFE channel in movies, as I am using a 2 channel dac, and getting downmixed PCM from the dvd player.
To get much more, I would need to pony up even more money for a high excursion adire or ascendent audio woofer in a LT'ed sealed box, or sacrifice my relationship with my gf and build some huge vented contraption.
As an aside, I don't even think I get the LFE channel in movies, as I am using a 2 channel dac, and getting downmixed PCM from the dvd player.
RobWells said:
Hi rob,
The labs broken ik yet ?
Have you tried to eq. the labs to ~20 Hz?
Does it come close to the 2 tempests quality ?
R, Collin
I don't know why, but all the systems that I have heard, in which some effort was put to play the lower 10Hz to 30Hz range, were always unacceptably weak in the upper sub-bass, bass and mid-bass range (60Hz to 500Hz). By the way, I find this lack of energy balance quite disgusting.
Anybody check this out yet?
http://www.danleysoundlabs.com/DTS20.html
Some of the issues are addressed in this design. SPL is PDG. Group delay maybe not up to spec but nothing with a single driver even comes close to it!
Mark
P.S.
Refreshing to see posts coming from people who have done a bit of thinking before typing!!
http://www.danleysoundlabs.com/DTS20.html
Some of the issues are addressed in this design. SPL is PDG. Group delay maybe not up to spec but nothing with a single driver even comes close to it!
Mark
P.S.
Refreshing to see posts coming from people who have done a bit of thinking before typing!!
mazurek, you could go with passive radiators to keep relatively reasonable sized boxes. Some subwoofers now have a low Vas so can be used in smaller than usual boxes.
Seems like everyone here is only considering the speakers.
IMHO, one of the biggest faults of music on CD's is their inability to convey low frequency LOW LEVEL information. When the music stops, it's like a black hole - no sense or "feeling" of the room (or hall) the recording was made in.
IMHO, one of the biggest faults of music on CD's is their inability to convey low frequency LOW LEVEL information. When the music stops, it's like a black hole - no sense or "feeling" of the room (or hall) the recording was made in.
Most of the time it's not the CD fault.
Try a Telarc CD, I think you would like well recorded CDs.
http://www.telarc.com/Classical/title.asp?sku=CD-80539&mscssid=U7N8D8VSBB4U9M8SAP7XMXSE1HQ6D3MF
Try a Telarc CD, I think you would like well recorded CDs.
http://www.telarc.com/Classical/title.asp?sku=CD-80539&mscssid=U7N8D8VSBB4U9M8SAP7XMXSE1HQ6D3MF
You think?
In a didgital system there are fewer and fewer bits available as the amplitude decreases. With these fewer bits it becomes more difficult to accurately map slow slope changes (low frequency).
I believe didgital audio suffers from this problem. Low frequency low level information is inaccurate.
In a didgital system there are fewer and fewer bits available as the amplitude decreases. With these fewer bits it becomes more difficult to accurately map slow slope changes (low frequency).
I believe didgital audio suffers from this problem. Low frequency low level information is inaccurate.
Hanginon said:
Communication is the point of a forum.. not spelling unless it becomes seriously detrimental to communication.
Actually its the high freq.s that are difficult to reproduce without distortion for digital recordings.. not the low freq.s.
Additionally, it isn't a medium problem at all (at least within the limits of bit depth and rate) - its with the recording engineer and possibly post production where low freq. info. can be reduced or eliminated. But even that is comparitivly rare.
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