More sub questions...plenty vs. overkill?

[Bryant0086]

 

All things being equal that is correct.

 

The whole point of horn loading or using multiple drivers is to reduce cone movement which in turn reduces distortion for any given SPL.

Disclaimer: I admit my theory probably has little or nothing to do with the real world and is solely me just being a nerd.

 

  You know........ I actually sort of understand where you are coming from. Some receivers even offer a bass boost for low listening levels. However, I think it may be more our ears as opposed to the speaker not doing of it what is asked. I've never really thought about it until now though..

 

   Bryant

[DrWho]

http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/multsubs.pdf Edited February 19, 2015 by DrWho

[derrickdj1]

 

Who wants 30 subs? Larger subs have larger motors, not an issue at soft or loud listening levels. Now there is intergal calculus where you are chasing infinity and never get there. Four subs or four areas of stacked subs will give the best room response. Metro, if you are ever in Indiana, you have an open invite to hear my system.

I'm in Indiana. Just sayin'. ;-)

 

 

I am in the Northwest region and if you are up this way, it would be a pleasure to meet you and have some fun showing you the system and chatting audio.

 

 

 

 

4 corners would be slightly louder. 4 centered would give a slightly better response but they were close. That's how I remember reading it anyways.

 

This is correct.  The mid wall placement gives the best room response and the 4 corners the most output.  The room FR is excellent either way, or the best that we can get in a particular room.  Havig the subs slightly asymmetrical will avoid some cancellationa and reinforcement of certain frequencies due to room modes.

 

You can have more than 4 subs but, concentration them in 4 locations should give a good respones and increas output since the extra subs will be colocated.  This is fairly easy in a small HT.  To be mutually coupled, the sub has to be in a 1/4 wavelength or around 3 1/2 ft. at 80 Hz.

 

Here is  a graph of my room response with 4 subs:

Edited February 19, 2015 by derrickdj1

[dewthedru]

 

i moved from a place that had a fairly small basement where my trusty old HSU STF-3 never failed to move me. my current HT is much larger and i'm thinking i need to upgrade. i'm torn between DIY 18"s or getting 1 or 2 HSU VTF-15H's. i've actually toyed with the idea of just picking up another stf-3 but i can't find one anywhere. i've searched craigslist for the last year or so without any luck. 

my HT space is about 550 sq ft with 8.5' tall ceilings and carpeted concrete floors.  i've included the layout.

what do you think? would a single VTF-15 be plenty? i know more is always better but if it's totally overkill, i don't want to just throw money away. and i know some of you have already recommended building a couple of stonehendge 18"s but i don't want the bass to be ridiculous compared to the rest of my setup. (RF-35 fronts, RC-35 center, and RS-35 surrounds)

thoughts?

  Well since you said you would be interested in a DIY project, there are many out there you can google. They have everything from a small sealed 18 to a horn loaded one that isn't a difficult build, though it is QUITE large.

 

  Cinema F20

 

 

 

  Bryant

 

 

lolz....i cannot imagine putting that thing in my house!

[fuzzydog]

lolz....i cannot imagine putting that thing in my house!

 

Its so big that you'll hardly notice it's there. 

[mustang guy]

 

 

i moved from a place that had a fairly small basement where my trusty old HSU STF-3 never failed to move me. my current HT is much larger and i'm thinking i need to upgrade. i'm torn between DIY 18"s or getting 1 or 2 HSU VTF-15H's. i've actually toyed with the idea of just picking up another stf-3 but i can't find one anywhere. i've searched craigslist for the last year or so without any luck. 

my HT space is about 550 sq ft with 8.5' tall ceilings and carpeted concrete floors.  i've included the layout.

what do you think? would a single VTF-15 be plenty? i know more is always better but if it's totally overkill, i don't want to just throw money away. and i know some of you have already recommended building a couple of stonehendge 18"s but i don't want the bass to be ridiculous compared to the rest of my setup. (RF-35 fronts, RC-35 center, and RS-35 surrounds)

thoughts?

  Well since you said you would be interested in a DIY project, there are many out there you can google. They have everything from a small sealed 18 to a horn loaded one that isn't a difficult build, though it is QUITE large.

 

  Cinema F20

 

 

 

  Bryant

 

 

lolz....i cannot imagine putting that thing in my house!

 

Just tell people it's the bathroom. Paint a moon on the front.  

[mustang guy]

 

 

 

 

Why not get a pair of R-115SWs? A pair would do quite well in that space.

 

http://www.klipsch.com/R-115SW

 

Ideally, you should have 8 subs in a rectangular room: one in each corner which would negate the room mode effects. Reason being, no matter where you put a sub in a room, the corners are always loaded the most strongly. Hence, you instead load all corners as sources, and the net response is the smoothest possible. This might not be feasible for most. 

I think if you were to actually measure that, you'd find that your statement is false. There's a popular article about ideal subwoofer placement and the eight corners do not remove room modes. Maybe someone not on their phone can post it. The only solution I've seen is the dual zoned bass array.

 

I bet I would as well. Acoustic theory states as such only, hence why I said ideally (and hence why someone actually tested it per your statement). That was not intended to be taken seriously.

 

If you had 8 subs, and you could ceiling mount them, wouldn't centering them on the walls above and below in the cross configuration be the best? This would diminish the vertical standing waves.

 

By the way, here is a quote from the conclusion of the HK experiment:

 

"One subwoofer at each wall midpoint is the best in terms of

Std, Max-ave and Max-min but does not support low

frequencies particularly well. Two subwoofers, at opposing

wall midpoints, performs very nearly as well as four at the

midpoints and gives a much better LF factor. One

subwoofer in each corner also has good low frequency

support, but does not perform quite as well as one

subwoofer at each wall midpoint, in terms of Std, Max-ave

and Max-min. If cost and aesthetics are considered,

subwoofers at 2 wall midpoints is preferred. "

 

If money and WAF are not considered, then 8 giant subs. 

 

The conclusion above does not consider 8 subs in 8 corners. It does not specifically say the cross patter in better with 8.

 

Who has 8 identical subs that would like to do the experiment?

[dewthedru]

 

 

Just tell people it's the bathroom. Paint a moon on the front.  

 

 

 

hahaha.  that's a great idea.  but i don't want any drunks pooping on my sub.  

[Paducah Home Theater]

Four subs or  four areas of stacked subs will give the best room response.

I'm curious as to how room shapes affect this. Is a rectangle the same as a square? Wide the same as narrow? I'm not sure.

Metro, if you are ever in Indiana, you have an open invite to hear my system.

Somebody needs to organize a home theater crawl in the heartland. Long weekend road trip, tour around and visit multiple people's rigs. There isn't hardly jack crap around here.

[CECAA850]

I'm curious as to how room shapes affect this. Is a rectangle the same as a square? Wide the same as narrow? I'm not sure.

 

I would imagine the principal would apply to any parallelogram but a square is just about the worst shape for a listening environment. 

[DrWho]

Thankfully Room EQ Wizard will model various room shapes for you:

http://www.roomeqwizard.com/images/roomsim.png

Best part is the software is free...

 

The paper didn't go into length on it, but pulling the subs in 1/4 from the front/sides of the room had the best frequency response. However, I think the paper decided that it wasn't an acceptable option to consider....but we're audiophiles. None of this stuff is even close to aesthetically pleasing - even the fanciest rooms.

[beeker]

As others have stated in other threads some time/s ago on the klipsch forum is extended low frequency in back of you works wonders and a must. My setup is overwhelming in the front so another on the back wall works so nice. I can make 2 rocking chairs rock like somebody is rocking them. Im sure several around here can do the same

 

A sealed 15 in the center of each of 4 walls on the floor would be more than perfect in the larger than average room. then 2 ported 18's up front in corners and 2 sealed 15's in back which is a very good concept

 

 

best setup if possible would no be no doubt multiple horn loaded extended low frequency units evenly distributed in the room if possible center of each wall

 

 

spreading extended low frequency units around a room evenly is the goal and helps create premium extended low frequency. Spreading extended low frequency producers around a room as good as possible is a must. 2 in the front corners is good but adding more units within a room helps expand bass evenly within a room such as 2 more in the back corners. Tons of extended low frequency on one side of the room and not the other will normally exhaust itself. Once a unit that is in the back of the room is tuned to the room it proves itself easily. It is sort of like surround sound only for extended low frequency. It will truly prove itself better than shoving 30 units up against the wall. Those 30 up against the wall will produce a ton of extended low frequency but it will produce an extended low frequency bubble of waves that is not evenly distributed. Distributing those units evenly within a room will make sound quality and response much better. Simply putting 2 units in each corner then 2 units in the middle of each wall will sound better than 30 shoved up against the wall. Better than 30 up against the wall is 30 in each corner and in the middle of each wall total of 150 units. Maybe a room where the walls are made of drivers. Myself I would chose 15's lol then you could toy with the idea of covering the ceiling area and then to the floor possibly...I think you get the idea....this would produce the best possible sound quality

 

Distribution of units is simple and is key for quality extended low frequency. my room is about 400sq ft so calculations tell me I need would it be 240 15's or easier yet approx. 200 18's give or take. Better yet and maybe easier a room with al dts 10's on each wall would be ample. A room squared off with k1803's would be very comparable and choice at that point may be taste. You would not know till you tried lol

 

 

This is both the answer to sitting in a any room and producing best possible quality extended low frequency. It is not overkill and it does not have coverage issues.

[dewthedru]

You people are ridiculous

[Paducah Home Theater]

Better than 30 up against the wall is 30 in each corner and in the middle of each wall total of 150 units. Maybe a room where the walls are made of drivers. Myself I would chose 15's lol then you could toy with the idea of covering the ceiling area and then to the floor possibly...I think you get the idea....this would produce the best possible sound quality

 

Distribution of units is simple and is key for quality extended low frequency. my room is about 400sq ft so calculations tell me I need would it be 240 15's or easier yet approx. 200 18's give or take.

[Scrappydue]

Four subs or four areas of stacked subs will give the best room response.

I'm curious as to how room shapes affect this. Is a rectangle the same as a square? Wide the same as narrow? I'm not sure.

Metro, if you are ever in Indiana, you have an open invite to hear my system.

Somebody needs to organize a home theater crawl in the heartland. Long weekend road trip, tour around and visit multiple people's rigs. There isn't hardly jack crap around here.

home theater crawl up this way soon. Gonna be sweet

[derrickdj1]

Room modes are fixed by the volume of the room.  There location can chage wit room shape and which ones will be dominant will also change with the shape of the room.  The principal is still the same, 4 widely distrubted subs will give the best room response. 

 

Tactile sensation can change with nearfield vs far field sub placement.  Particle velocity will come into play.  In the nearfield the particles are not in phase for a large area of the room.  In the farfield placement the particle velocity is in phase and more unifrom throughout the room.  Neither is superior and it depends on multiple factors on which is best for a particular room.

[Bryant0086]

 

 

i moved from a place that had a fairly small basement where my trusty old HSU STF-3 never failed to move me. my current HT is much larger and i'm thinking i need to upgrade. i'm torn between DIY 18"s or getting 1 or 2 HSU VTF-15H's. i've actually toyed with the idea of just picking up another stf-3 but i can't find one anywhere. i've searched craigslist for the last year or so without any luck. 

my HT space is about 550 sq ft with 8.5' tall ceilings and carpeted concrete floors.  i've included the layout.

what do you think? would a single VTF-15 be plenty? i know more is always better but if it's totally overkill, i don't want to just throw money away. and i know some of you have already recommended building a couple of stonehendge 18"s but i don't want the bass to be ridiculous compared to the rest of my setup. (RF-35 fronts, RC-35 center, and RS-35 surrounds)

thoughts?

  Well since you said you would be interested in a DIY project, there are many out there you can google. They have everything from a small sealed 18 to a horn loaded one that isn't a difficult build, though it is QUITE large.

 

  Cinema F20

 

 

 

  Bryant

 

 

lolz....i cannot imagine putting that thing in my house!

 

 

  Yeah but the good news is that you only need to build 8 of these to handle your room appropriately. ^__^

 

  In all seriousness, there are lots of choices out there for DIY subs, even kits. I will probably go that route one day.

 

    Bryant

[Paducah Home Theater]

I'm usually happy with my two 18's at the volume I listen at, but noticed recently that if I have the gain up like I like and strong material gets played, they are sometimes just really violent. That can't be a good thing. I originally wanted some more for some help at 15-20 hz, but maybe adding some more would make them chill out a little while retaining the same volume at higher frequencies than that.

Edited February 23, 2015 by MetropolisLakeOutfitters

[CECAA850]

sometimes just really violent

 

How so?  Do they make a clacking sound?  Chuff?  Does it just sound slightly distorted?

[Paducah Home Theater]

sometimes just really violent

 

How so?  Do they make a clacking sound?  Chuff?  Does it just sound slightly distorted?

There is only one movie that can make them "clack", which is them bottoming out on the intro of transformers 4, but I'm talking about up higher. Just seems like the box is about to fly apart sometimes possibly due to a resonance. It typically happens on the upper end of those obnoxioius sine wave sweeps that are in movies for dramatic effect, probably approaching 80 hz, I'm guessing somewhere between 50 and 80. I don't know if it is the driver, or box resonances since I used birch plywood, or maybe because it is sitting on loose/thick carpet and may be moving. I have to drive them pretty hard for them to do this. They just sound overdriven when they have a decent amount of power up high for a subwoofer and I can't describe it. Down low and flexing hard they do well, standard LFE where things go thump is fine. I noticed it a little last night on RoboCop, some of the gunshots from his futuristic pistol comes through the subs and it sometimes sounded like they could benefit from some more control somehow. They are sealed boxes so no chuffing, either driver distortion or box resonance, maybe something in the room is rattling and confusing me, I don't know.

Edited February 23, 2015 by MetropolisLakeOutfitters