Subwoofer for Sleeping Kids? Help Define my Requrements.

[diesel_88]

I'm designing a 5.1 system so my wife and I can watch movies after the kids are in bed. I've got my arms around the satellites--using Zaph's bargain designs--but I'm puzzling over the subwoofer. My five-year-old's bedroom is right over the living room, and I don't want to shake him out of bed. I'm looking for well-integrated, adequate musical bass, but I'm willing to sacrifice the realism of feeling every explosion. And we're obviously not going to listen at high levels.

How do y'all suggest I define this in terms of the speaker response curve (alignment, F3, slope, etc.)? I don't have a lot of experience with the low end of the spectrum; never had a sub before.

Cam

[johnnyrichards]

Bass shakers can be a viable "silent" alternative.

[daryl]

I'm designing a 5.1 system so my wife and I can watch movies after the kids are in bed. I've got my arms around the satellites--using Zaph's bargain designs--but I'm puzzling over the subwoofer. My five-year-old's bedroom is right over the living room, and I don't want to shake him out of bed. I'm looking for well-integrated, adequate musical bass, but I'm willing to sacrifice the realism of feeling every explosion. And we're obviously not going to listen at high levels.

How do y'all suggest I define this in terms of the speaker response curve (alignment, F3, slope, etc.)? I don't have a lot of experience with the low end of the spectrum; never had a sub before.

Cam

You might turn down the LFE level at night or you might turn the LFE off altogether at night.

You can turn down the volume if you like and leave the LFE level alone.

Bass shakers are less audible than a sub (in theory but I have never like the idea of them myself).

One thing you might be able to gain some benefit from is exploiting proximity to your advantage.

I typicly place my sub with my mains but if you instead locate the sub at the listening position (behind the couch for instance) you will have to reduce it's level to maintain proper balance because it is so much closer.

Also you will gain some rejection of room modes with this placement and you will require a sub with less output capability.

This is not the best way to prevent localisation of the sub and listeners not located within arms reach of the sub will not get the same balance also it would be best if your reciever had a distance adjustment for the sub (not all of them do).

[Jason]

Yeah, something like bass shakers may actually be about your only option. Bass has a tendency to pass right through walls - I just got in trouble with the Mrs. the other night because my sub was "rattling the windows" two stories up, and I didn't even think I had it turned up all that loud.

You may actually be better off skipping a sub and building some larger main speakers (if you have the space). You definitely won't get the low lows, but it can still be an adequate experience. Or you could just kick the sub on when no one is sleeping... or turn the sub down a little at night.

Do you have a budget in mind? How large of a box are you willing to live with? Do you ever plan on using this system at higher levels (i.e. when noone is sleeping), and if so, how loud and low do you want to go?

If you're on a tight budget and aren't looking for extreme performance, you may want to look into some of the Dayton pre-assembled systems, as they appear to be a pretty good bang for the buck.

[Bruce]

Hey Cam.
BassShakers for sure!
http://i46.photobucket.com/albums/f138/technimac/BassShakerInstallation007web.jpg
I installed 4 in our couch, 2 in the loveseat and they are a major hit for anyone who experiences "tactile" LFE in movies. Believe me, they'll even be a hit with your 5 yr old, because almost all kids' movies have tons of LFE stuff in them and BassShakers will do it justice. For instance, in WallE, when the space ship takes off, the couch is rumblin'.
Yes, it's also a good idea to have a sub too, but it can be turned down a huge amount (when your son is sleeping), and the BassShakers will give you that bottom end punch.;)
Still, having the sub at low volume really helps to integrate the BassShakers with the rest of your system.
It's also quite amazing how our brains can do an excellent job of stitching together the LFE we experience from BassShakers with that from the sub and the rest of the sound system.
Want music? Turn off the BassShakers and crank up the sub.
Here's a post on my Quatro 15 sub and BassShakers: http://www.htguide.com/forum/showpost.php4?p=290701&postcount=38
HTH

[HT-EXT]

I will haft to agree that bass shakers are the only way to go in this situation. My neighbors use to complain about big booms in the middle of the night but all that change when I got the shakers. Listen levels have been lower 15db to 20db and everyone is happy especially me. I also reduce subwoofer size down from 15"s to 10"s also help. The 15"s could be heard next door where the 10"s hit hard and fast but do not seem to bother anyone yet. Just my two cents.



HT-EXT

[billfitzmaurice]

How do y'all suggest I define this in terms of the speaker response curve (alignment, F3, slope, etc.)? I don't have a lot of experience with the low end of the spectrum; never had a sub before.

CamBass goes through all but the most robust, ie., six inch solid concrete, walls and floors as if they weren't there. When the kid's asleep turn the volume down as low as required or use headphones.

[Dirk]

Check your receiver for a "night" setting. It will probably apply more dynamic range compression (to bring the center channel & surrounds forward) and also cut a lot of the low bass.

[Todd G.]

I also reduce subwoofer size down from 15"s to 10"s also help. The 15"s could be heard next door where the 10"s hit hard and fast but do not seem to bother anyone yet. Just my two cents.

HT-EXT

I would have thought that a given frequency reproduced at a given volume would sound generally the same whether the sound originated from a 15" driver or a 10" driver.

[Todd G.]

Hey Cam.
BassShakers for sure!
http://i46.photobucket.com/albums/f138/technimac/BassShakerInstallation007web.jpg
I installed 4 in our couch, 2 in the loveseat and they are a major hit for anyone who experiences "tactile" LFE in movies.

Since you seem to have the bass shakers mounted facing each other on opposite sides of the couch structure, wouldn't they tend to counteract each other?

[jmc]

Maybe he wired them out of phase.

[Todd G.]

Maybe he wired them out of phase.

That's what I was wondering. I've been thinking about ordering some of these, and when I saw the picture, I thought they would just cancel each other out unless polarity was reversed.

[Dirk]

My advice with shakers is to cross them as low as possible. Even if you have them crossed at 80hz in the receiver, use the XO on a plate amp and crank that dial low.

The Aura ones have a really strong, high-Q Fs peak around 40hz. If you have access to a PEQ, notching that out seems to allow them to play a bit higher.

[HT-EXT]

I have notice with the expansion of my system that bigger is not always better. The 15" subs have more surface area which in turn moves more air. This allows for a lower tuning with the correct enclosure. By using a larger sub the sound travels a greater distance and is easily heard from far away. The 10" subs have less surface area and will produce low bass but do not carry as far as the 15"s. Up close the 10"s are very impressive and will hit hard and fast but not as low. Of course volume control is the main factor. If you turn either up loud enough you will still wake the neighbors. With the 10"s you are able to get excellent sound at a close distance with not alot of carry. If I am wrong someone please correct me. I say build a couple of 10"s and put them as close as possble to the main seating area. If you can put one up front and one behind but still not disturb the kids, even better.



HT-EXT



Oh Yeah! Don't forget the shakers !!!

[Bruce]

Since you seem to have the bass shakers mounted facing each other on opposite sides of the couch structure, wouldn't they tend to counteract each other?

Sorry, that photo didn't show the install very well. Actually, two are mounted on vertical plane, with the bases both facing the same direction, so they're in phase.
I had to install a couple of 1" x 6" boards to mount the other two on the horizontal plane, (with both bases facing up also wired in phase).
I was also careful to mount them as close to the back support uprights as possible and away from the couch feet on the floor. That way, most of the "action" is conducted to those sitting on the couch and not to the floor.
I also ran a fillet of Polyurethane glue along every frame joint that was accessible to further strengthen the couch. YMMV on that one.;)

Here's a better picture of them mounted, along with the buyout Audiosource amp that powers them. (it's not mounted in that position, just placed there for the photo)
http://www3.telus.net/public/a6a43712/Bass%20Shaker%20Installation%20009%20web.jpg

Todd - BassShakers do make a huge difference. Wiring out-of-phase IS necessary IF the BassShakers (on the same plane) face in different directions. In this case, I was careful to keep them facing the same way.
For six shakers total, they are wired series/parallel, giving a load of ~6ohms to the amp. It's gain is set to ~60-70%.
Dirk, Good point. Yes, these are crossed low, because that is where most of the "tactile action" is.
Cam, I'm wondering if a Dayton RSS315HF-4 12" Reference sub in a 2 cu ft sealed box with a Bash 300W amp might be a fine match for these and suit your purposes well. Small enclosure and excellent SQ - Great for both movies and music.
HTH

[Todd G.]

I have notice with the expansion of my system that bigger is not always better. The 15" subs have more surface area which in turn moves more air. This allows for a lower tuning with the correct enclosure. By using a larger sub the sound travels a greater distance and is easily heard from far away. The 10" subs have less surface area and will produce low bass but do not carry as far as the 15"s. Up close the 10"s are very impressive and will hit hard and fast but not as low. Of course volume control is the main factor. If you turn either up loud enough you will still wake the neighbors. With the 10"s you are able to get excellent sound at a close distance with not alot of carry. If I am wrong someone please correct me. I say build a couple of 10"s and put them as close as possble to the main seating area. If you can put one up front and one behind but still not disturb the kids, even better.

HT-EXT

Oh Yeah! Don't forget the shakers !!!

I'm not trying to be difficult, but for the sake of others that might read your post, I feel compelled to point out that it is almost entirely wrong. The "fast" issue has been covered elsewhere, so I'll leave it alone and let you look it up to confirm the truth or lack thereof implied by your statement. But the rest of your statement is like me saying that a 3000hz tone played through a dome tweeter @ 100db is louder than a 3000hz tone played through a ribbon tweeter @ 100db. I think(hope) that you would quickly call BS on this, but that is pretty much that scenario you've set up, only in your example the drivers are of different sizes. So let's say a 1" dome playing at 3000hz @ 100db is louder than a 1/2" dome playing 3000hz @ 100db. Can you smell the BS?

The sound coming from a single speaker(point source) will dissipate at a predictable, repeatable rate regardless of the size of the speaker, be it 8", 10", 12", etc. If you're producing 40hz @ 100db, the "carry" will be the same for sound coming from an 8" driver as it will be from a 15" driver. For it to be otherwise would require that the sound possess intelligence and "know" how it was produced and then somehow read your mind to play only as loudly as you wanted so as to limit "carry".

Your perception that the 10" somehow produces less neighbor disturbing sound is likely based on the fact that they produce less neighbor disturbing sound, i.e. low bass. Lower freq sound does move more easily through walls and ceilings, so the fact that the 15" can be heard further away may have led you to believe that it has more "carry" when in reality it is just producing freqs that the 10" is not.

The fact that you think the 10" is "fast" and "hits hard" in comparison to the 15" would tend to indicate that you have a poorly designed 15" sub, a poorly designed 10" sub that produces little sub bass, or both.

[spasticteapot]

I might suggest a single 10" sub - say, an RS265 - in a sealed box in combination with some bass shakers? You'd need two plate amps - one running directly off the LFE of the receiver to power the sub, and another set to cross over at 30hz for the bass shakers, conveniently just below both the lowest frequency a sealed RS265 can produce and the aforementioned peak in the shakers' response.

[Bruce]

I might suggest a single 10" sub - say, an RS265 - in a sealed box in combination with some bass shakers? You'd need two plate amps - one running directly off the LFE of the receiver to power the sub, and another set to cross over at 30hz for the bass shakers, conveniently just below both the lowest frequency a sealed RS265 can produce and the aforementioned peak in the shakers' response.

To clarify a bit. Run a line from the "LFE/Subwoofer out" on the receiver then use a "Y" splitter to run the LFE signal to the sub and BassShakers. It's not necessary to "crossover" the sub at 30 Hz, but he can set the BassShaker sub crossover for 30Hz. One of the things with a sealed alignment that works well, is that the sub's gentle roll-off provides a smooth transition to the BassShakers. I think that's what that spasticteapot was getting at.

Cam hasn't noted the size of his room. If he's got a small room, the RSS265HF-4 will probably do - and the price right now is very attractive.

I suggested the 12" Dayton RSS315HF because it'll perform well in small and larger rooms.
Here's the RSS315HF response in an optimum-sized sealed and vented alignment.
http://i46.photobucket.com/albums/f138/technimac/RSS315HFventedsealedresponse.jpg
HTH

[Dirk]

The frequencies that bother people are the boomy ones -- 60hz to 120hz. Not the bottom octave. So I just don't think switching to a smaller driver is of as much help as turning down the gain of your existing one and adding some bass shakers to give that "high SPL" feeling.

Now, if that smaller driver also happens to be higher quality/lower distortion, then the odds of you having boomy response is reduced, at least anechoically (all bets are off in-room). So in that regard, the 10" RS idea is not a bad one. Another good idea is simply sitting closer to the sub. Try finding a new subwoofer location that's closer to the listening area.

[billfitzmaurice]

I would have thought that a given frequency reproduced at a given volume would sound generally the same whether the sound originated from a 15" driver or a 10" driver.+1. It would sound exactly the same unless there was a dispersion difference, but that's not the case in the sub-bass. If it sounds different the response is different, and of course that has little to nothing to do with driver size either.

[diesel_88]

Excellent ideas; thanks all. I hadn't considered bass shakers. It's easy enough to put the sub close to the couch.
My receiver has a late-night mode which I'll use, but it sounds like the consensus is mostly "turn it down." No problem; by the time the kids are in bed, we're in sound overload!

[HT-EXT]

I apologizes for any mis-information and I do not want to tell anyone the wrong thing. I did say that the 15"s could be tune to play lower than the 10"s. I don't remember saying one was louder than the other at any given frequency. I agree with you TODD G. and I will not begin to think I am a pro at this audio thing like Bill and you. I am a novice and at best a bad novice. IMHO the 15"s play lower frequencies which in turn can be heard further away(carry), which you did pointed out but my example was way too vague. I feel for the given situation 10"s will provide good performance without playing the lower frequencies at a disturbing level. Again my opinion. BILL F. and TODD G. I would like to know your opinions on what would work best 15"s or 10"s???



HT-EXT

[HT-EXT]

TODD G
If you're producing 40hz @ 100db, the "carry" will be the same for sound coming from an 8" driver as it will be from a 15" driver.

So let me get this right you are telling me that if my set up was in a basement and that the 8" sub would be as loud upstairs as the 15" would be?



HT-EXT

[Dirk]

TODD G

So let me get this right you are telling me that if my set up was in a basement and that the 8" sub would be as loud upstairs as the 15" would be?
HT-EXT

Over the frequencies that both are capable of producing at the same SPL, yes. If the 8" has an F3 of 25hz and the 15" has an F3 of 20hz, obviously that lowest 1/4 octave wil be "louder" on the 15", but then again, you don't actually hear that and it won't be the "boom" that bothers people the most anyway. "Boom" frequencies are higher.

[Taterworks]

Consider this:

Many listeners will manually set their subwoofer 10dB above the level of their main speakers, simply because they like the extra LF energy in the room -- in fact, a friend of mine regularly listens at an RTA-verified 25dB higher.

If you build your theater around a set of full-range main speakers (with the ability to play to 30-ish Hz), you can simply leave the subwoofer on LFE duty (running your mains full-range), then turn the subwoofer off and keep the volume low when you want to be quiet, and the amount of wall-traversing subbass will be greatly, greatly diminished.