Surround Subwoofers

There one good way I know of to do this, and it's essentially what you thought of as option #1. The first thing I'm assuming is that you want the "directional bass" to make sense with the content you're watching/playing. This would mean that you have to send only the appropriate information to each subwoofer, so that when an explosion happens to the right of the screen you won't hear/feel it on the left. This also implies that you won't want to hear/feel explosions that happen in front of you, behind you. The best way I know to do this would be to have channel specific subwoofers, or really big speakers. Since you probably don't have really big speakers I would suggest the following:

If your subwoofer has speaker-level inputs/outputs, run the speaker wire for each surround channel through the appropriate subwoofer (then to the rear speaker), and set the crossover on the sub where you want (so that it plays only the low bass that it can handle). This basically filters out the low bass for the sub and allows the rear speakers to play the rest. Be sure to set your rear channels to full range in your receiver's menu. It's important here that your subs have speaker level outputs as if you have to split the speaker wire or make separate runs to the subs and the rears it will force your rears to play at full range, which they may not be able to handle, and they could be damaged.

The other issue here is that you'll probably want a 3rd subwoofer located up front, so that the effects that happen in front of you will have the same sense of "directional bass." Just use the main subwoofer output for this one (unless you want to do 6 subwoofers - one for each channel plus the LFE).

Hope that helps.

I run a dual Velodyne setup, with the two subs daisychained.. if you have a 7.2 AVR, then that is probably the simplest solution

There is no good reason to do this. Bass is non-directional. There is no such thing as "directional bass".

Bass below 80 Hz is not directional.. it's low frequency energy. The higher-frequency information provides the directional cues that tell your ear/brain where the sound is coming from. In many cases, the upper-bass octaves of the woofer reproduce those sounds. The typical frequency range for a consumer subwoofer is about 35-200 Hz. Thus, above 80 - 100 Hz, bass is, in fact, directional.

What are you trying to do, exactly, vrekks? Will these subs be dedicated to surround channel bass only or are they the only subs in your setup? Do you have another sub (or subs) for the rest of your bass (front, center, and LFE channel)?

I thought it was understood that I was referring to below 80Hz. I guess I should have clarified.


It depends, in a well-implemented system, you will not be able to tell where the bass is coming from.

Just to clarify for you: You will still need a dedicated subwoofer to produce the ".1" sound, which is the LFE channel. Adding subwoofers to the other speakers just makes them more capable of producing low frequencies. BUT: What's your crossover set to in the AVR? What are the speakers set to (small or large / full size)? All those things will influence how much sense your idea makes.

In case you didn't know:

In a typical 5.1 setup, the 5 speakers can produce a certain range of the sound. Ideally / theoretically this is from 80Hz and up. Then the .1 subwoofer produces all the sound that's below 80Hz. Because sound <80Hz is non-directional, it doesn't matter to your ears and brain where the speaker that's producing the <80Hz content sits. (Room placement does influence the performance of the sub, but that's a whole different topic.)

One reason why speakers are split up like this in a typical HT system is that reproducing bass takes a LOT more power than reproducing high frequency content. By putting the <80Hz responsibilities on the 1 subwoofer, you can keep costs down, because the other 5 speakers don't all have to be beefy powerful speakers.

Your AVR is typically set up to take all the <80Hz content from the 5 channels and send that to the sub instead of the normal speakers. This is accomplished by setting the crossover in the AVR to 80Hz, and setting the size of speakers to small. That way your AVR knows that your speakers are not meant to / capable of producing the <80Hz content, and that the sub will take care of it instead. In addition to the <80Hz content from the 5 channels, the sub will also get the .1 LFE content. This is where the real rumbling typically is. So in a typical 5.1 setup, the sub does double duty as low bass speaker for the LFE channel as wall as bass speaker for the other channels.

So, in your scenario, you adding subwoofers to the other channels is of limited use. You would have to be able to tell your AVR that those speakers which are now accompanied by a subwoofer are full-range / large speakers so that the AVR will send the <80Hz content to those speakers instead of to the dedicated sub. Not all AVRs allow you to specify that on a per-speaker basis though, and only allow you to specify it for a set of speakers at a time. So you would have to check your AVR to make sure it even supports doing this.

And then even if you do it, the question is if it will make a noticeable difference. As stated before, the <80Hz content is non-directional, meaning that regardless of where the subwoofer is placed, you can't really tell where it's coming from. So there's limited value to doing what you're proposing to do.

Without debating the psychoacoustic elements of your question, I can suggest REL Acoustics to accomplish what you want mechanically. The T-Series are small and would fit nicely next to your gaming chair.

Most or all of their subs have a Lo and Hi input. The Hi input connects to the amplifier's speaker level outputs, so the attached sub sees only the information for that particular speaker. This of course requires you to set your surround speakers to Large in the menu, so Bass Management does not remove the below 80Hz signal. Rel.net for more information.

If it's a 5.1 system, why not find two more of these Kenwood floorstanders (or a comparable speaker) for use as the surround speakers. Since the fronts provide "all the 'front base'" you need, then using them as surrounds should have similar results without having to fiddle with anything on the receiver. And since you're looking to locate subs in that area, I would imagine floorstanders would fit the same footprint.

The biggest problem with this scenario is assuming that surround right and left speakers are actually located at a place where it will allow them to produce accurate LFE. This is almost never the case. I don't think there is any good reason to try this.

Adding subs is always beneficial, but I don't see the point to add them in a fashion so that they will integrate into the surrounds. There are more harms than benefits in that approach.

For what you want to do, the Crowson stereo tactile transducer system would be your best bet.
http://www.crowsontech.com/go/crowso...opDefault.aspx
http://www.crowsontech.com/go/crowso...opDefault.aspx
Hook them up to the front L/R channels and place them on either side of your seating. "Steered" Tactile Motion will provide much better directionality than trying to utilize the directional bass from the surround channels with nearfield subwoofers. There is very little directional bass in the surround channels. There isn't a lot in the front channels either, but there would be more than in the surrounds. Plus you could set up the transducers to output at higher frequencies and then you would have a lot more directionality. With subs, if you set them up to output higher frequencies, you get localization of sounds you don't want localized to the subwoofers. Transducers don't have that problem.

Short of that, I don't really think that the system you're proposing would work the way you want it to work.

Craig

According to this Tomlinson Holman interview, [paraphrasing by me!] "80Hz is two standard deviations below the minimum frequency at which Swedish Radio's most sensitive test panelist could detect directionality" (whatever that really means!) Which suggests to me that for most people (perhaps almost everybody!) the non directional bass regime really extends from 20hz to 160Hz, 320Hz, or even 640Hz . . . and why "good" AVRs allow crossovers well above 80Hz. Plus, if I'm not mistaken, the SDDS (theater) LFE range is up to 330Hz (and I doubt we should draw the inference that SDDS believes 331Hz is directional!?)

You are making it more technical than necessary. The localization depends on the wavelength and distance if you want to be technically accurate. 80Hz is a good round number though.

I really don't think all this makes any difference in answering OP's question anyway.

I don't think it will harm the subs, but I don't think the subs will get much use. At least not for the frequencies they were built for.

Again, if, in your words, the Kenwood fronts provide plenty of bass, what's stopping you from getting two more identical or at least comparable floorstanders and using them for surrounds? You don't have to do any futzing with tone controls or b zones or anything other than hooking them up and calibrating them to the rest of the system.

If the bass needs to be deeper than what the Kenwoods provide, then I would split your subwoofer preout using splitters and route the LFE signal to two more subs. If necessary get a receiver with two sub preouts. At least then the subs would get the signal they're built for, and you'd have tons of bass (assuming good subs are purchased.)

This won't get you what you're after because you'll be getting the bass information from the front speakers, not the rears.

I agree with Tulpa that the easiest thing to do would be to get bigger rears and let them play full range back there.

Otherwise the only thing to do is as I previously suggested: get 2 subs with speaker level inputs to dedicate to each rear channel, and set the rears to full range in the receiver.

This then leaves the question of what happens to your LFE channel. If you don't get a third sub, your fronts will play the LFE - although not as effectively as a sub. So you probably would want another sub, at least eventually.

I'm not sure how much bass information games will have in the rear channels. It'll be interesting to hear how this comes out once you get it done.

It may. Higher frequencies may cause localization of your subwoofer. This is bad.

I will say this one more time. Any low frequency data is not localizable. This means that it makes no difference whether they originate from your left or right speaker. Adding additional subwoofers is advisable because it will improve your room's bass response. However, when you add additional subwoofers, it is extremely critical to place them at a location where they will result with the optimum low frequency response. That location will almost NEVER be where your left and rigt speakers are located. Thus, by locating those woofers next to your speakers, you are effectively negating all the additional benefits that you are likely to get from adding subwoofers with your poor placement choice.

By all means, buy the subwoofers, but place them where they perform best and not near your speakers. What you are after is just NOT a good idea from an audio science perspective.

So are you talking about getting passive subs to add to your current rears instead of larger rear speakers? First of all you are going to find that there is not a lot of bass info in the rears channels for most content. Even games that have 5.1 output will adhere to the standard that bass comes from the sub on the .1 channel. Second, if you already have a sub out on your receiver, and if you use powered subs, you can hook as many of them up as you like by simply splitting the RCA sub output with splitters. And finally, while bass is non-directional, it does couple very well, so as you add subs it is typically better to add them close to each other so that you get the desired gain effect. Adding another sub, the goal is usually to achieve more volume at lower frequencies than with a single sub, this is much better accomplished by placing your additional sub next to or on top of the first one. Post #24 in my sig has a basic example of dual subs in an HT system, they are split using an RCA splitter from the sub output of my prepro.

If it's tactile sensations you want, you'd be better off with a set of buttkickers. At least those would work the way you want them to.

Very true.

Better check the specs on your reciever, 5.1 or 7.1 recievers dont usually have discreet amps for A and B, and if they do, it likely doesnt have the ability for separate bass and treble for those channels. If they are discrete channels, you could use F-Mods to cross those channels over, they are cheap inline crossovers that you can find with google or at parts express. The recommendation for tactile tranducers is likely a better idea for the effect you are describing, even a cheap pair of aura bass shakers would do the trick, also available at parts express. I am getting ready to pull the trigger on 6 of them for my theater soon.

This might help you out a bit, I was rather confused about the issue:

http://www.avsforum.com/avs-vb/showthread.php?t=1241816

I am just going to get a Behringer and hook 4 or 5 subs up to that. One line out of my AVR, into the Behringer, line out to each of the subs or amps running the subs depending on what I end up with, EQ etc as required from there.

If a sub has binding posts for speaker wire, they can receive an amplified signal. I think there are also adapters that switch wire to RCA coaxial cable.

The sub out is a variable line level, so you set the gain on the sub, then the reciever volume controls the volume of the subs and speakers at the same time. The reciever wont have stereo output for the sub LFE channel though, if you are looking for stereo bass, you will need to get it from your main channels, and set those channels to Large speaker so they get bass to them. Still not sure if what you are describing is going to be the best solution, and if your reciever doesnt have preouts for the main channels, you may need to find subs that accept speaker level inputs.

For F-Mods, stick with 80Hz, that seems to be a good crossover point for almost all subs as it is the THX standard that most adhere to.

I have had both Buttkickers and Crowsons and found the Crowson units to be a better choice for my tastes.

As far as the bass being non-directional, I think it is mostly marketing driven. I can hear which direction sub 80 Hz bass is coming from although it isn't as obvious as higher frequencies. I have always run full range speakers on all channels (and I mean true full range that can put out serious output at 20Hz) and I have yet to hear a system that uses speakers with less extension and all the bass sent to one sub that has ever been able to approach the authority and command of a multi-sub or 5+ true full range system.

Bass being non-directional is less about marketing and more about the physics of our heads, the ears positioned on either side of them, and the brain being unable to tell the difference in the phase of the sound wave when it reaches one ear versus the other ear when the wavelength becomes sufficiently long.

When a person loses hearing in one ear, they also lose the ability to localize sound. This is because the brain localizes sound by telling the time difference from when the sound reaches one ear versus the other ear. The brain tells this time difference because the sound wave will be at a different phase when it reaches one ear than when it reaches the other ear.

Therefore, logic dictates that when a sound wave is sufficiently long, the brain will be unable to tell to localize it because the difference in the phase of the sound wave when it reaches one ear versus the other will be so negligible that it will appear to the brain that the sound arrived at both ears at the same time and, therefore, it will be the same as though it was heard with only one ear, unable to be localized.

Considering the dimensions of the human head and the relatively long periods of low frequency sound waves, it's quite reasonable to assume that when you get down low enough, you're probably going to reach the frequency where it becomes difficult or impossible to reliably localize a sound well before you get into infrasonics or even deep bass (meaning sub-80Hz). Studies conducted have, I believe, supported this.

As for the OP's idea and his seeming desire to feel the booms in his games coming from one side or the other (my understanding of his desire anyway), I don't think even on that level that it will work out the way he thinks it will. But, it's his money and his time so if he wants to try it out, cool. Hell, it'll be kinda interesting if it does produce the effect he's looking for.