1.
So how do you insure that you have a seamless transition between main speakers and subwoofer?
Most main speakers will be flat to around 40hz. In my case, I'm using venting tuned to 40hz in my main system.
Now, lets say I want to add a sub to get 20-40... how do I do that without muddying up my 40-100hz range?
I'm thinking I should apply a high pass filter to my main speakers and a steep crossover low pass to the sub.
Maybe a bandpass is the solution as I don't need to worry about its crossover, just the main system.
2. How many bass drivers is too many? I could use one or two drivers. But would it make sense to use as many as 4 or 5 drivers?
Where's the point of diminishing returns with lowering linear distortion by using multiple drivers?
O
O
O
OO
OO
O O
. O
O O
OOO
OOO
OOO
So how do you insure that you have a seamless transition between main speakers and subwoofer?
Most main speakers will be flat to around 40hz. In my case, I'm using venting tuned to 40hz in my main system.
Now, lets say I want to add a sub to get 20-40... how do I do that without muddying up my 40-100hz range?
I'm thinking I should apply a high pass filter to my main speakers and a steep crossover low pass to the sub.
Maybe a bandpass is the solution as I don't need to worry about its crossover, just the main system.
2. How many bass drivers is too many? I could use one or two drivers. But would it make sense to use as many as 4 or 5 drivers?
Where's the point of diminishing returns with lowering linear distortion by using multiple drivers?
O
O
O
OO
OO
O O
. O
O O
OOO
OOO
OOO
Daveis said:
1:
A) Proper subwoofer location and level. There are of course several methods to finding the best suitable location for a subwoofer. Find one that works best for you and go from there.
B) Simple. Either allow the mains to play fullrange and cross over the sub near the natural roll-off of the mains (40Hz or so), OR cross both the mains and sub over at or above 40Hz. Personally, I would go with the second option just to take away some of the bass duties from the mains. This would "clean them up" a bit so to speak throughout their entire range.
2:
A) Depends on how deep your wallet goes, also depends on the size of your room and how loud you want to go.
B) Again, it depends on the size of your room. You could use several smaller subs scattered around the room to help fill any nulls that may reside in the room. This can and will flatten the overall room response in most all seating positions when done correctly.
C) Again, this depends on how loud you want to go. If you are wanting to go for reference levels, and if your room is rather large or "leaks" sound, you may want to go with multiple drivers. More drivers will load the room more efficiently, will lessen the work load on all the drivers (lowering linear distortion), and if positioned in different locations, will flatten the room's response.
Some people have 2 subs, one in a corner and one somewhere midway on a wall. Others will go as far as to have one sub per channel (5 or 7 channels with 5 or 7 subs).
You speak of 4or5 as if it's excessive
, Check out the Cult
Paul W's dual 24" Hartley IB (seen on gallery page 1) was replaced with TWO of these manifolds each containing 9 Parts Express DVC 15"s.
http://home.comcast.net/~infinitelybaffled/Pauls_IB_Gemini_GalleryPic.jpg
, Check out the CultPaul W's dual 24" Hartley IB (seen on gallery page 1) was replaced with TWO of these manifolds each containing 9 Parts Express DVC 15"s.
http://home.comcast.net/~infinitelybaffled/Pauls_IB_Gemini_GalleryPic.jpg
Multiple drivers mainly mean less linear distortion and more SPL.
After modeling in Unixbox, I see that 4 drivers doesn't do much for the low end extension all else equal. But it might allow 4 inexpensive lower Xmax drivers to make good sound.
In the case of my friend who tasked me to come up with a low extension sub... I don't think he is ready for Cult of IB. His home theatre room does have a wall in the back that's connected to his "computer room". That would be a tough sell. I have him convinced that he can live with 6-10 cu feet box though.
Only one person chimed in with a suggestion of bandpass box. I am wondering if that's because they are a sonic compromise or just no one is building them?
I am wondering how to best deal with room gain? My buddies room is far from flat... I notice almost everyone puts their sub in one far corner... Ok, you get some wall loading, BUT... if you don't measure your room's response how do you know that you aren't compounding a bad room gain problem???
After modeling in Unixbox, I see that 4 drivers doesn't do much for the low end extension all else equal. But it might allow 4 inexpensive lower Xmax drivers to make good sound.
In the case of my friend who tasked me to come up with a low extension sub... I don't think he is ready for Cult of IB. His home theatre room does have a wall in the back that's connected to his "computer room". That would be a tough sell. I have him convinced that he can live with 6-10 cu feet box though.
Only one person chimed in with a suggestion of bandpass box. I am wondering if that's because they are a sonic compromise or just no one is building them?
I am wondering how to best deal with room gain? My buddies room is far from flat... I notice almost everyone puts their sub in one far corner... Ok, you get some wall loading, BUT... if you don't measure your room's response how do you know that you aren't compounding a bad room gain problem???
Daveis said:
A) And a flatter room response throughout.
B) The way four drivers would help extend the bottom end any is only by increasing overall output by having all of them in the same location (corner). IOW, instead of being down say -15dB @ 15Hz with one driver, with four drivers in one location, you would now only be down about -6dB @ 15Hz. You could then use an EQ to cut back on that extra +9dB gain at the higher frequencies all the way up to the xover point so they blend in with the mains at the same output level. This means your system would have the potential of only being -6dB down from the xover point to 15Hz instead of being down -15dB at 15Hz from the xover point.
C) A lot of people have a hard time considering cutting a large hole in their wall or ceiling to install an IB system. And you can't just put it anywhere either. You have to treat the location of an IB sub in the same manner as a traditional box sub.
And keep in mind, depending on your friend's room, a 6-10cf enclosure can be rather huge as well, and he may desire something much smaller.
D) From what I have read, bandpass designs are very bandwidth limited. And since the cone of the driver is not in direct contact with the air in the room, some feel (including myself) that a bandpass design isn't the best sounding. If poorly designed, they can be very boomy and have a "one-note" sound to them.
I personally wouldn't recommend one for home audio/theater use. But that's just my opinion.
E) Trial and error. If you have no way of measuring the room's response (and a lot of people don't), use the next best method... your EARS.
1) Try to achieve the flattest response with position first.
2) If more tweaking is required, use an EQ to knock out any peaks.
3) If after all of that you still have deep nulls (suckouts) in the bass response, you may want to consider an additional subwoofer located in the largest null in the room to help fill out that null.
4) If you still need more tweaking, then figure out some kind of room treatments.
I would perform these methods in this order. The reason I would leave room treatments as a last resort if because they can get very pricey very quickly, and they can eat up valuable floor space.
Just as a reference, I have my sub on the front wall right along side my center channel, which puts it about 4' away from the nearest corner. I still have very usable bass extention down to 12-14Hz, but also have a flatter room response because of that position.
For some perspective on this issue, from my own experience in cinema applications, most cinemas sub bass boxes use 18" drivers and are on average tuned -3db at 31 hz, by stacking these units, ie x4, a -3db of 25hz can be achieved.
Most cinemas usually use only 1 sub bass unit per installation on average. ( THX installs use more but are a minority) Cinema sub bass is usually created electronically in the mixing suite, ie not naturally sourced and are artificial by nature. Cinemas stage channels Speakers are mostly -3db from 40 hz.
A notable number of American cinemas are still mono! even in some of the 10 percent of screens that have swapped to the new 2k digital image systems which are starting to replace 35mm film projection, Australian commercial cinema houses tend to be at least dolby surround and 35mm film. (35mm film has the potential for 3500 lines of resolution)
As for 2k digital, yes its specs are very similar to that of 1080p home systems. 2060 x 1080 v 1920 x 1080 (hd dvd, blueray), Sony have released a new 4k digital system for cinemas which is closer to the full potential of 35mm film. (perhaps exceeds in quality)
Personally unless you are an organ fan, aiming for less than 25 hz is probably not good bang for buck. Most people who listen to pop/rock, 35-40 hz would be considered a very impressive sound ! ie value for money!
Most cinemas usually use only 1 sub bass unit per installation on average. ( THX installs use more but are a minority) Cinema sub bass is usually created electronically in the mixing suite, ie not naturally sourced and are artificial by nature. Cinemas stage channels Speakers are mostly -3db from 40 hz.
A notable number of American cinemas are still mono! even in some of the 10 percent of screens that have swapped to the new 2k digital image systems which are starting to replace 35mm film projection, Australian commercial cinema houses tend to be at least dolby surround and 35mm film. (35mm film has the potential for 3500 lines of resolution)
As for 2k digital, yes its specs are very similar to that of 1080p home systems. 2060 x 1080 v 1920 x 1080 (hd dvd, blueray), Sony have released a new 4k digital system for cinemas which is closer to the full potential of 35mm film. (perhaps exceeds in quality)
Personally unless you are an organ fan, aiming for less than 25 hz is probably not good bang for buck. Most people who listen to pop/rock, 35-40 hz would be considered a very impressive sound ! ie value for money!
Cameron Glendin said:
Most of JBL Pro Cinema bass bins and all of Klipsch bass bins are tuned to around 30-40Hz as you say, however JBL does have a couple models that are tuned to 22Hz.
I'm not sure of what cinemas use here or there, but I don't think people are wanting their home systems to sound like commercial cinemas. I know I sure don't!
Most cinemas sound like garbage unless they are owned, operated and designed by IMAX or Walt Disney. Like you said, a good number of them are still mono, or at least sound like they are. I have never liked the sound of any cinema I've been to EXCPET for a few Disney have in Orlando, FL.
And this is where I disagree with your post.
I feel that when you have the means to design and build your own home theater system, you do so to have it sound and look much better than anything at the local cinema. Even my modest hodge-podge system blows away any cinema in my area, and to a degree, even better than the Disney ones.
I'm sorry, but if you limit yourself to ONLY 25Hz, you're going to be missing out on a lot of information in movies and music.
Even comparing my system that reaches down to 12Hz to my brother's system that reaches down to 18Hz, there's still a lot of sub-20Hz information that you get out of my system that just isn't present in his, and that's only a 6Hz difference! And it's not because my system is twice as big and powerfull as his. When played back at the same (below reference) levels, mine still offers quite a bit more information that's not only heard, but felt.
So in short, don't limit your system to ONLY 25Hz just because that's what the cinemas do. Who cares what they do. The whole point behind our hobby is to make ours sound better than the pros.
Daveis said:
Sure you can, if you have a room as big as a commercial cinema. And especially the IMAX theaters, they use very large format sound systems with loads of power.
Here's just one example that I've found. Be sure to check out the "Products" tab on the top of the page. Very nice, fun items there!
http://www.eaw.com/news/index.html?id=166
As far as your second question, I guess building something similar to Altec's Voice Of The Theater speakers would be closest to the real thing, since Altec dominated the cinema for many years until JBL pretty much took over. You just can't beat the sound of a large, super efficient horn taking care of all the sound above 500Hz or so. Large 15" efficient drivers for everything below 500Hz to take care of the rest. Then finish off with some really good 15" subwoofers capable of reproducing bass WELL BELOW 25Hz (aim for at least 20Hz, if not less) and you're in business.
Hmmm...a ways back, there was a discussion here regarding Eminent's TRW-17 rotary woofer, including some DIY effort for rolling your own (and avoiding a $13,000 price tag). Has there been any further effort on this?
It doesn't seem to me to be an impossible thing to do, especially when you're trying to beat the price of a commercial unit.
It doesn't seem to me to be an impossible thing to do, especially when you're trying to beat the price of a commercial unit.
JWilliams said:
It certainly isn't impossible to do. Like I said, I've got useful output down to 12Hz with a pair of Dayton 15" DVC drivers in a 6.3cf sealed enclosure. If I can do it for well less than $1000 (Crown amp included), there's no reason anyone else can't do it.
I'd say to get the best results the most practical and least expensive way, stick with large 12"+ drivers in decent sized enclosures and you'll be fine.
Sure, huge bass horn designs that are builting into the ground below the listening room, or huge horns extending out the wall and into your neighbor's back yard, or exotic rotary "woofers" that mimic antique electric fans from the 1920's are fine and dandy, but at a huge cost of not only buying and building the things, but also altering a large portion of your house as well which is a huge expense in itself, especially if it doesn't turn out the way you had hoped.
chops said:
My most immediate plans involve a subwoofer or two using a Peerless XXLS 12" woofer in a ported box tuned to around 20 Hz. However, the basic idea and functionality of a rotary woofer does seem pretty straightforward, with the caveat that you need some darned big air reservoirs to install it (e.g. a secondary air chamber under the floor). And, of course, it's tough to beat a bass extension down to 1 Hz or so.
Whether or not you would actually make use of that much bass extension on a regular basis is, of course, an open question. Perhaps you could simply play the Telarc 1812 disc over and over
JWilliams said:
And, of course, it's tough to beat a bass extension down to 1 Hz or so.
Whether or not you would actually make use of that much bass extension on a regular basis is, of course, an open question. Perhaps you could simply play the Telarc 1812 disc over and over
True, but how many electronics even go down to an honest 1Hz anyway? Most electronics tend to start rolling off around 7-10Hz, some even higher.
The title of the thread is " 10 to 25 hz, is it necessary for HT or music .
In my opinion it is not necessary for most people, I tend to think of it as a expensive luxury. I do agree that deeper is better, its just that it gets to a stage that its a lot of money for a smallish return on most recordings. ie bang for buck.
Personally at the moment at home I am limited to 35hz and am more than happy with the effect, It even impresses most of my friends, most of all my wife! who suffered with a 8 ft long sonotube cannon style sub in the living room for a bit too long. She personally did not hear the benifits of a 22hz sub. She sees the improvement of the 35hz sub box. Each to their own!
Unfortunately the huge size of the jbl enclosure to create the 22hz note will not fit backstage in your average cinema, and is more likely to be found in a catalogue than at your local multiplex.
In a cinema at least, the room might actually be big enough to allow the genuine and accurate formation of a 40 ft long 30hz (ish) wave. um what is the size of a 10hz wave again?
Some do use cinema components for in their home system, I find Lenards opal 4 way active systems are the finest that I have experienced as yet.lenard audio check out their horn loaded approach for cinema.
This is a photo of one of my local cinemas speaker systems!! The only Lenard system of its type so far in the world today.
In my opinion it is not necessary for most people, I tend to think of it as a expensive luxury. I do agree that deeper is better, its just that it gets to a stage that its a lot of money for a smallish return on most recordings. ie bang for buck.
Personally at the moment at home I am limited to 35hz and am more than happy with the effect, It even impresses most of my friends, most of all my wife! who suffered with a 8 ft long sonotube cannon style sub in the living room for a bit too long. She personally did not hear the benifits of a 22hz sub. She sees the improvement of the 35hz sub box. Each to their own!
Unfortunately the huge size of the jbl enclosure to create the 22hz note will not fit backstage in your average cinema, and is more likely to be found in a catalogue than at your local multiplex.
In a cinema at least, the room might actually be big enough to allow the genuine and accurate formation of a 40 ft long 30hz (ish) wave. um what is the size of a 10hz wave again?
Some do use cinema components for in their home system, I find Lenards opal 4 way active systems are the finest that I have experienced as yet.lenard audio check out their horn loaded approach for cinema.
This is a photo of one of my local cinemas speaker systems!! The only Lenard system of its type so far in the world today.
Attachments
To reach 10Hz with any authority, your friend is going to need many big subwoofers and lots of floor space or an IB configuration, which is likely to PO all his neighbors since the back wave is vented to the outside of his house. In a 15x20 room unsealed you'll need a half dozen or more 18" subs to rattle the windows.
EDIT: Oh... and very little audio is ever heard below 20-30 Hz. That said... that last octave... if done right... costs a BUNCH of $$$.
EDIT: Oh... and very little audio is ever heard below 20-30 Hz. That said... that last octave... if done right... costs a BUNCH of $$$.
I think my buddy is happy with flat to 20hz. He was being a little overzealous with requesting a system below 20hz. His current 12's in a sealed box only do (he estimates) downto 30hz strong.
If I had to guess I'd say my dual 12" Daytons were doing that already and for much less money than his current setup.
If I had to guess I'd say my dual 12" Daytons were doing that already and for much less money than his current setup.
"big enough to allow the genuine and accurate formation"
I just don't understand it. Why must people think a room has to be a certain size before you can hear certain bass frequencies? It's total BS.
If that were the case, you wouldn't hear anything below 1000Hz with headphones.
All I have to say is that I'm glad I'm not some of you guys who think anything below 35hz is useless. If your ears are that far gone, then you need to be investing in hearing aids, not stereo equipment.
And how many times do I have to say that it doesn't cost a fortune to build a subwoofer capable of sub-20Hz bass?!
Spend $750 at Parts Express on a pair of Dayton 15" DVC drivers and a Crown XTi 1000, build a sealed 6.3cf enclosure, configure the drivers in a push-pull fashion, and you've got yourself a DIY subwoofer system that (when in the right room) will provide usable output down to 12Hz. And trust me, it's plenty loud enough to rattle the windows and doors in my house very efficiently.
If a subwoofer only reaches down to 35Hz, then it is useless and shouldn't even be considered a true subwoofer.
I just don't understand it. Why must people think a room has to be a certain size before you can hear certain bass frequencies? It's total BS.
If that were the case, you wouldn't hear anything below 1000Hz with headphones.
All I have to say is that I'm glad I'm not some of you guys who think anything below 35hz is useless. If your ears are that far gone, then you need to be investing in hearing aids, not stereo equipment.
And how many times do I have to say that it doesn't cost a fortune to build a subwoofer capable of sub-20Hz bass?!
Spend $750 at Parts Express on a pair of Dayton 15" DVC drivers and a Crown XTi 1000, build a sealed 6.3cf enclosure, configure the drivers in a push-pull fashion, and you've got yourself a DIY subwoofer system that (when in the right room) will provide usable output down to 12Hz. And trust me, it's plenty loud enough to rattle the windows and doors in my house very efficiently.
If a subwoofer only reaches down to 35Hz, then it is useless and shouldn't even be considered a true subwoofer.
Back to the original question:
My opinion- no (but you know what they say about opinions )
I use 4 of the Dayton 8" DVC drivers (long story why) and they work from 50 to 30 hz. They rarely actually kick in. Yet everyone is amazed at the deep pure effortless sounding bass.
But, this is a DIY forum. And if someone wants to go down to 1 hz, then, I say, party on! Reading about each others attempts to their personal idea of perfection, is what is so fascinating about this forum.
I must admit that I have personally gone to the PE web site to read up on those 15" DVC drivers since reading this thread! just curious!
Fun stuff!
My opinion- no (but you know what they say about opinions
)I use 4 of the Dayton 8" DVC drivers (long story why) and they work from 50 to 30 hz. They rarely actually kick in. Yet everyone is amazed at the deep pure effortless sounding bass.
But, this is a DIY forum. And if someone wants to go down to 1 hz, then, I say, party on! Reading about each others attempts to their personal idea of perfection, is what is so fascinating about this forum.
I must admit that I have personally gone to the PE web site to read up on those 15" DVC drivers since reading this thread! just curious!
Fun stuff!