Room Acoustics vs. Sub size/type

[Nate1272]

How much does having an open wall on one side of your room effect your sub performance. I am asking because we have decided to open put an 8 foot opening in a room that is 12ft x 18 ft. the 8n foot opening will go on the 18ft wall. My setup will be facing going with the long axis of the room.

I recently have been looking into sealed subs due to some recommendations here on the forums. I am about 80-20% music to HT. I know sealed subs tend to work better in smaller places and our room originally was not going to have this large open spot on the wall.

So my question is.... Does this open wall make a significant difference in the rooms acoustics( by the way..the other walls area is about 60% windows.) . Will a ported subs tend to be less boomy in the open room? With the significan amount of windows( which I know are very reflective of sound) be cause to keep with the idea of a sealed sub.

Any guidance would help..
thank.

[kexodusc]

Your open wall will have an impact on acoustics, but it's difficult to predict how much or in what way. You'll likely lose some loudness, a db or two, but also some reflections that might be adding a bit of echo or muddiness to the sound.

Boominess is hard to predict too...the ported sub won't be any less boomy than a sealed sub, and if 80% of your listening is music, you're probably better off going sealed, all things equal.

[Nate1272]

The room I am asking about hasn't been built yet. It is the only room that will be available for an HT/music room in my house when it is completed. I don't really know how much echo it will have, but I assumed the windows would only add to the echo and muddiness. I figured that by opening the room up on one side it would decrease some of the echo. I was planning on getting an 8-10" sealed sub from either Velodyne or AV123 at first. I was just wondering if opening the room up would warrant a larger sub.

[gjpham]

My H.T room is like yours with a big 4'x8' opening window right on the right side and it's killing me. I'm not sure how much your sub will suffer but I'm getting alot of echo. I plan to put draperies to cover up this window soon.

[shokhead]

My sub is in the corner of a window and a slider. The wall behind it runs to open into the kitchen,about 25-30ft. Otherway opens into the living room,maybe 50ft. My sub works fine,you just have to tweek and setup.

[Nate1272]

I have thought about putting draperies on the windows but I do not know how much that will eliminate the a problem with the bass. I know cloth draperies will absorb some of the high frequencies, but won't do much for the bass. I have looked also into some other acoustic treatments such as bass traps and such if the room will warrant it. Auralex offeres free room analysis and such when the time comes so I might look into that.

[gjpham]

I have my 2" wedge foams from www.FoamForYou.com and they work great, big diff and cheap.

[Sir Terrence the Terrible]

The issue with subwoofers and openings into other rooms becomes an amplitude and low bass extension loss issue. Your subwoofer will not only "see" the room it is in, but any other room connected by an opening to that room. So if you are purchasing a subwoofer for a 2000 cubic foot room with an opening to another 2000 cubic ft room, you need two indentical subwoofer to achieve a simular loudness and extension to a 2000 cubic foot room with no opening. Each opening to another larger room will require another sub with more ultimate loudness and extension. This is why custom installers usually build enclosed hometheaters with acoustically sealed doors to other rooms. It minimizes low frequency losses due to the additional space the subwoofer must fill.

The room I am asking about hasn't been built yet. It is the only room that will be available for an HT/music room in my house when it is completed. I don't really know how much echo it will have, but I assumed the windows would only add to the echo and muddiness. I figured that by opening the room up on one side it would decrease some of the echo. I was planning on getting an 8-10" sealed sub from either Velodyne or AV123 at first. I was just wondering if opening the room up would warrant a larger sub.

Echo comes from reflections in relatively large rooms with walls parallel to each other. It is usually found in high frequencies and create an effect known as slap echo in most small rooms. These are better controlled through the use of room treatments, not opening up the room. The only thing that opening up the room will solve is bass induced room modes. It will also make the sub have to work harder to acheive X loudness.

If you have not built this room yet, you would better serve yourself by enclosing the room in with four walls with doors to exit the room(hopefully overall room deminisions are rectangular in shape) and using some decorative room treatment to solve the slap echo problem.

[dmb_fan]

Don't worry about it.

And for goodness sake, don't worry about whether to buy a sealed or ported subwoofer! There are good subwoofers made from each design. Your purchasing choices should be dictated by how much you are willing to spend and how loud and low you need a subwoofer to go. If you have an infinite budget, a good choice might be a brand new sealed Velodyne 18", or it might be the crazy ported SVS model with 4 12" drivers. Both will blow you away. Neither is any better than the other simply because they are sealed or ported.

And (this is just the voice of reason, so feel free to ignore it) you should build the room that makes the most sense aesthetically and ergonomically, unless this is solely a HT room and nothing else.

If anything, the low bass loss that Terrence describes (which is 100% correct) will lessen your issues with standing waves and make it easier to EQ your sub. Overall high SPL's might be harder to achieve, but don't forget that the sub's response is also dependent upon how far it is from you. If you have a huge room (a problem a buddy of mine has) simply place the sub behind the couch. You'll have awesome bass response at your listening position no matter how large the room is.

Echo problems are only measurable and understandable once the room is built and are best dealt with (as Terrence says) with room treatments. You've already found Auralex, and they have plenty of great products that will help you tame echoes.

The bottom line is: any good sub will perform well in any room. The best scenario is a sealed room, but this isn't always possible. My sub lived for a time in a "room" that was separated by 8'x7' openings to rooms on either side, so it "saw" a much much larger room than it was in. But with a parametric EQ and proper placement, I had a perfectly flat frequency response (at 1/6th octave intervals) down to the sub's stated 25Hz roll-off point.

I hope that helps a little.

Best wishes,
Adam

[kexodusc]

Don't worry about it.

And for goodness sake, don't worry about whether to buy a sealed or ported subwoofer! There are good subwoofers made from each design. Your purchasing choices should be dictated by how much you are willing to spend and how loud and low you need a subwoofer to go. If you have an infinite budget, a good choice might be a brand new sealed Velodyne 18", or it might be the crazy ported SVS model with 4 12" drivers. Both will blow you away. Neither is any better than the other simply because they are sealed or ported.

To be fair here, to say one design is "better" depends on its intended purpose, and what you're looking for. But don't discount the very large differences created by this design choice. All other things kept equal, a ported and sealed sub will have very different properties. Depending on the intended use, performance expectations, and budget, one would be better than the other.

[topspeed]

I've found this thread from Rich Greene to be one of the most instructive with regards to subs. You might find it interesting.

BTW, am I the only one that thinks a 8-10" sub is going to have a hard time in that size of a room? Unless it's one of these new long excursion jobs, I'm curious if it will move enough air, especially with the opening.

[Geoffcin]

BTW, am I the only one that thinks a 8-10" sub is going to have a hard time in that size of a room? Unless it's one of these new long excursion jobs, I'm curious if it will move enough air, especially with the opening.

Best bet is a good 12" sub. Espcially if it's also for HT.

[Nate1272]

Thanks for all the input. I actually talked to my contractor about the situation and I decided we will just put a couple of pocket doors into the walls so I can close them whenever I want. Thats about the best of both worlds in my situation I would think. I will just treat the echos with some acoustic treatments.

I actually just purchased an Onix Rocket ULW-10. With closing in the opening I think it should be enough bass for me. I listen to mostly music as of right now. If in the future HT becomes a more significant interest I will look into a larger sub.

[Geoffcin]

Thanks for all the input. I actually talked to my contractor about the situation and I decided we will just put a couple of pocket doors into the walls so I can close them whenever I want. Thats about the best of both worlds in my situation I would think. I will just treat the echos with some acoustic treatments.

I actually just purchased an Onix Rocket ULW-10. With closing in the opening I think it should be enough bass for me. I listen to mostly music as of right now. If in the future HT becomes a more significant interest I will look into a larger sub.

They have a tendancy to rattle in their tracks the wall.

[Nate1272]

They have a tendancy to rattle in their tracks the wall.

Well thanks for bursting my bubble....

I'll put french doors then possibly, pocket doors are just much more convienient.

[Geoffcin]

Well thanks for bursting my bubble....

I'll put french doors then possibly, pocket doors are just much more convienient.

Dimmer switches are the worst EMF emitters in the world. Guaranteed to cause buzzing in your sound system.

[thekid]

Dimmer switches are the worst EMF emitters in the world. Guaranteed to cause buzzing in your sound system.

Geo

Learn something new every day.......

Re the dimmer switch issue.
Is it a distance thing or a problem just having them hooked anywhere in the house?

[dmb_fan]

I've got a dimmer switch in my living room, where I have a very nice stereo plugged directly into the wall with no line conditioning mumbo-jumbo and I have no audible EMF problems.

Just FYI. YMMV.

-Adam

[dmb_fan]

To be fair here, to say one design is "better" depends on its intended purpose, and what you're looking for. But don't discount the very large differences created by this design choice. All other things kept equal, a ported and sealed sub will have very different properties. Depending on the intended use, performance expectations, and budget, one would be better than the other.

I respectfully disagree. I am of the opinion that good subs exist from both design types, and purchases should be dictated by price and loudness/lowness capabilities.

"All things being equal" (meaning same box, same amp, same driver) a ported sub will play lower and louder than a sealed sub. But of course, all things are never equal. The important design considerations are low frequency response and SPL capability (and of course, price).

-Adam