Why limit a subwoofer

[MrBoat]

to just frequencies 80hz and below, when the subwoofer's frequency response goes so much higher? The ultimax 12" for example, has a frequency response of 20-1000hz. Could this not be used to some advantage? Am I misunderstanding the meaning of "Frequency response?" To my newbish understanding, that makes it seem as if the driver will handle frequencies of up to 1000hz. On the other hand, I don't want to make such assumptions. I understand that the reason most subwoofers are crossed over lower is because the mains handle the higher frequencies. But there has to be a situation, at least in music, where there are times where a subwoofer has room to spare, because music is not always so busy in all the frequency ranges. There's only so many instruments etc.

The reason I ask is, I was playing my music in CD Direct, which sounds awesome, actually. So, I crawl down by the sub, making sure nobody was watching, and I listened to what was going on. Holy crap, the ultimax sounds great in the higher frequency ranges too. I could hear bass guitar notes that sounded quite nice that I could not hear before when I had it crossed over from 80hz.

Everything I read about subs is people wanting to go low as possible. What happens if someone doesn't need to go so low? Seems like kind of a waste. There's more to it than that of course. I've been trying a lot of different things, just out of curiosity.

Where CD direct has been working really great is, on older recordings, and the sub has actually been doing really well just let to run wild. A lot of different sounds I was not hearing before when it was dialed in to specific settings or limitations.

 

[-Jim-]

MrBoat,

Fundamentally subwoofers are added to a system to reproduce the low frequencies most speakers manufactured today aren't capable of producing at reasonable levels. (The volume produced at these frequencies is simply too low.) Those speakers work perfectly fine reproducing frequencies above these low bass sounds, and don't need subwoofers to assist there.

The cross over frequency where the Sub becomes engaged should not be turned down to the crossover point (80 Hz) set for the Fronts / Center / Rears, etc. in your home theater setup. That point is where the Bass management system in your receiver will start to divert signals from those speakers to the Sub where they can be better reproduced. Most Receiver OEMs suggest if you are using an LFE input, which is recommended if available, you set the crossover point on the subwoofer to it's maximum (Some lowpass filters go up to 120, 140, or about 200 HZ.) and let the Receiver do the rest. (Please advise your Sub setting / input.)

As for the ultimax 12, that is a "raw speaker" supplied by Dayton Audio. It may be capable of 20-1000 Hz in the right enclosure, with the appropriate signal & amplification, but additional output at those frequencies above about 150 Hz are not needed in most Home Theater Systems. And if someone would allow them to be produced by their Sub (most start to cut off at the lowpass values above) you would get an unbalanced sound field with the Sub "beaming" midrage sounds from it's location. Frequencies below about 80 are deemed almost non-directional, and the ability to perceive direction improves as frequencies rise. (Hence the beaming from the Sub.)

I'm thinking you may need to set your system up again to adjust your Sub settings.

I hope this was helpful.

 

[William Lemmerhirt]

Jim said many true things here, and I'll just echo a little bit. Using a single subwoofer above 80ish can indeed call attention to itself, and subwoofer localization is extremely distracting. Another side effect is the detraction of soundstage and imaging. A special thing about a property set up system is ss&i. Much more than just sounding good, you can really be in the music. Ok, back to bed...

 

[PENG]

I agree with both Jim and William. Depending on your room and placement, even setting crossover to 80 Hz can result in some localization because as explained, the receiver's digital filters use a slope similar to analog filters, that is, it is not a brick wall. So the sub will get significant response above 80 Hz. That isn't typically an issue for HT movie enjoyment.

 

[j_garcia]

On the sub side the slope is usually very steep - as much as 24dB/octave so it DOES get filtered out faster than the mains, which are often at 12dB/octave. This allows the mains a smoother transition to the sub.

 

[shadyJ]

You can use a higher than 80 Hz crossover without having localization ruining the soundstage if you put the subs near the mains. If you have one sub, put it up front right between the mains, two subs place them next to each main. They can sound better then speakers in higher than 80 Hz ranges because they are so much more capable in bass playback, and also they are less susceptible to floor bounce effect.

 

[William Lemmerhirt]

One thing about placing subs right next to the mains is, the best place for mains is usually not the best place for subs. Sometimes it does work out, but you have to experiment to know for sure.

 

[MrBoat]

Thank you for all the good answers.

A few things. One being, what I have found I am really enjoying is, the main speakers running uncolored from the receiver's built in tone controls. This has happened a few times when I tried direct mode. Apparently, the 12" Eminence woofer, as applied in the Fusion Tempests, is a really good one, all the way down to the lower 40's that it is rated to.

ShadyJ also hit on the exception, with having the sub closer to the mains. I believe that in my situation, my room is also helping to make this the exception to the rules. In any event, I cannot find either the main speakers, or the subwoofer in the room, or differentiate between left or right, except on some older recordings where it was obviously an added effect of them intentionally rolling a certain instrument from right to left, like on a drum solo. The good parts of all this being, it makes it convenient for the subwoofer being closer to the mains, and a true 2 channel, stereo experience. Which is also why I choose 2 channel for music instead of surround. After reading a lot around the net, I believe very few people are doing this. The theatre/movie surround setup, at least as an aside, is much more prominent, if not inescapable.

This is a stage forward setup, music only. It's ok if the location of the speakers is at one end of the room. Part of which, is the mental picture/focus of just knowing it is there. If I don't focus, I don't notice. In other words, I have to be physically really close to the speakers to tell which is doing what. Otherwise, it sounds like all of it is coming right out of the TV screen itself, or the receiver even, which is right in the middle of everything. If you look down at the sub, which you can see moving, you'd swear everything is coming from that, or that too. Sometimes I laugh at this visual mind trick.

I should also add that I am not trying to be an exception to the rules or contrary to the popular audio consensus. What I am really after is tonal quality and low distortion. CD direct, with a sub still manages to pull this off in a stereo effect. I think the difference really happens when trying to use smaller and efficient satellite speakers or mains that don't have much low frequency capability, if at all.

Just trying alternative things.

 

[j_garcia]

Polk and Bose (and various others, just examples of known ones) have tried this and to some extent, it worked. Polk's old sub sat systems only went to like 100Hz and Bose cubes are supposedly only good to about 200Hz, so the included sub/"bass module" fills in the mid to low achieving small appearance with adequate bass for the average person. Those don't extend low though, part of the tradeoff of using a sub for midrange. Most larger drivers will not handle the upper midrange as well; going to a smaller one that does well there usually means giving up some extension. Vocals are key to me and the critical range usually sounds better coming from the speakers themselves to me, so you need enough midrange extension in the mains to cover it before it blends to the sub.

Proper config to me does mean it should sound mostly like one speaker or one source unless you have things that are one side or the other or panning.

 

[MrBoat]

I don't have vocals coming from the subwoofer. I did get some of the bass notes from a regular guitar. It didn't clash with the mains or anything like that. I also set the sub to just overlap the lowest frequencies of the main speakers a bit. That sounds pretty righteous.

 

[TLS Guy]

I don't have vocals coming from the subwoofer. I did get some of the bass notes from a regular guitar. It didn't clash with the mains or anything like that. I also set the sub to just overlap the lowest frequencies of the main speakers a bit. That sounds pretty righteous.

The whole concept of augmenting speakers with a sub is crude. It only works at all because this one size fits all crossover is occurring at a low enough frequency that the ear is relatively insensitive to the mayhem.

Ideally all crossovers have to be custom to the drivers and the enclosure. You can never design a good speaker with an off the shelf crossover. The crossover must pay attention to the bandwidth, acoustic responses and sensitivities of the drivers involved. If not then the speaker will not sound good.

If you drive a sub higher up than is usual then the crossover would have to be custom. In addition most sub drivers will be into either a falling response, or more likely a rising and rocky response due to being driven into cone break up. So a sub driver very likely will go to 1000 Hz or higher, but the response will not be pretty. In addition the sub would be easily localized.

I know that an integrated design is preferable to the one size fits all second order high pass and fourth order low pass. This came out of the old THX specs, which specified sealed speakers so that the second order high pass and the second order roll off of the sealed speakers, resulted in a fourth order combined acoustic and electrical response. In this way there was a symmetrical fourth order response, or you at least had a passing chance of achieving it.

To design an integrated design and capture the LFE signal pretty much requires a DIY design and build.

Unfortunately the proliferation of subs has resulted in a proliferation of speakers with poor power handling and cone displacement limitations below 100 Hz.

However if capable speakers are involved, then I strongly recommend and prefer speakers be set to large and run full range and subs used very gently to augment speakers below their natural acoustic roll off. To me that sounds a lot better.

I have a strong suspicion that a lot of what people think are room problems are actually expected problems of using a one size fits all crossover.

 

[Pogre]

Thank you for all the good answers.

A few things. One being, what I have found I am really enjoying is, the main speakers running uncolored from the receiver's built in tone controls. This has happened a few times when I tried direct mode. Apparently, the 12" Eminence woofer, as applied in the Fusion Tempests, is a really good one, all the way down to the lower 40's that it is rated to.

ShadyJ also hit on the exception, with having the sub closer to the mains. I believe that in my situation, my room is also helping to make this the exception to the rules. In any event, I cannot find either the main speakers, or the subwoofer in the room, or differentiate between left or right, except on some older recordings where it was obviously an added effect of them intentionally rolling a certain instrument from right to left, like on a drum solo. The good parts of all this being, it makes it convenient for the subwoofer being closer to the mains, and a true 2 channel, stereo experience. Which is also why I choose 2 channel for music instead of surround. After reading a lot around the net, I believe very few people are doing this. The theatre/movie surround setup, at least as an aside, is much more prominent, if not inescapable.

This is a stage forward setup, music only. It's ok if the location of the speakers is at one end of the room. Part of which, is the mental picture/focus of just knowing it is there. If I don't focus, I don't notice. In other words, I have to be physically really close to the speakers to tell which is doing what. Otherwise, it sounds like all of it is coming right out of the TV screen itself, or the receiver even, which is right in the middle of everything. If you look down at the sub, which you can see moving, you'd swear everything is coming from that, or that too. Sometimes I laugh at this visual mind trick.

I should also add that I am not trying to be an exception to the rules or contrary to the popular audio consensus. What I am really after is tonal quality and low distortion. CD direct, with a sub still manages to pull this off in a stereo effect. I think the difference really happens when trying to use smaller and efficient satellite speakers or mains that don't have much low frequency capability, if at all.

Just trying alternative things.

I lucked out with that too. I lugged one of my subs around our living room, den and kitchen for about 5 hours one day taking spl measurements at every location from my seat. I did get the best measurements up front, but not right beside each speaker. I'm not quite equilateral to them from where I sit, but I don't have any localization issues.

 

[MrBoat]

Unfortunately the proliferation of subs has resulted in a proliferation of speakers with poor power handling and cone displacement limitations below 100 Hz.

This is what seems to be an ever present issue. A lot of which follows form over function. With my personal take on audiophilia, I don't get this direction. That seems it would be more suited for 'optiphilia,' or the need for something to look good above all else. I have listened to systems that employ bookshelf sized speakers in rather large rooms yet the subs are huge. To me, it sounds as if the main speakers are near their limit regardless of their ratings or measurements. Right or wrong, this experience is what directed me towards larger drivers and cabinets. Otherwise, it seemed as if smaller speakers were going to have to be very expensive ones.

However if capable speakers are involved, then I strongly recommend and prefer speakers be set to large and run full range and subs used very gently to augment speakers below their natural acoustic roll off. To me that sounds a lot better.

This is where I am at now. This has been the best combination so far. Again, I am using it for music only. I'm sure this makes a difference, at least in a stereophonic sense. It also seems as if the subwoofer needn't be so large, comparatively. Or at least sized to the actual amount of bass that's needed, or perhaps missing.

I have a strong suspicion that a lot of what people think are room problems are actually expected problems of using a one size fits all crossover.

That seems likely. Also, I don't think the open and often irregular floor plan with high ceilings helps either. It seems as if speakers would have to be custom built all the way around. I think spaces used to be more forgiving. Speakers just had to have low distortion and be big enough. My rooms are sort of small comparatively and rectangular. The layout puts the speakers at the small end. Smaller room means averaged sized furnishings are going to disrupt any possibility of standing waves from occurring easily. Probably why I get away with the silliness that I do.

 

[MrBoat]

I lucked out with that too. I lugged one of my subs around our living room, den and kitchen for about 5 hours one day taking spl measurements at every location from my seat. I did get the best measurements up front, but not right beside each speaker. I'm not quite equilateral to them from where I sit, but I don't have any localization issues.

Mine is actually out in front and off to one side, yet toed in towards the opposite. It's actually aimed toward the sofa on the opposite side. I get about the same amount of bass from 5 feet away, all the way to the kitchen, down the hall etc. The hallway is open at both ends. Almost as if my room is acting like a transmission line enclosure. The fact that the mains are running full range, yet higher up into the seated position, transmit the sound the same way. I have no dead spots.

I tried the sub crawl. I could not find a discernable difference, and my cables are not long enough to reach into the kitchen.

 

[Johnny2Bad]

Probably the main reason why Subwoofer-optimized drivers do not normally operate at higher frequencies is they are unsuited to the job in comparison to other driver sizes and types.

Perhaps the "short answer" is there are far more criteria necessary for good reproduction than simple frequency response.

Now, it's not unheard of to try. But you are introducing compromises that probably could be managed better with a more suitable mid/woofer.

 

[MrBoat]

Probably the main reason why Subwoofer-optimized drivers do not normally operate at higher frequencies is they are unsuited to the job in comparison to other driver sizes and types.

Perhaps the "short answer" is there are far more criteria necessary for good reproduction than simple frequency response.

Now, it's not unheard of to try. But you are introducing compromises that probably could be managed better with a more suitable mid/woofer.

The mains woofer is actually very good. Too good perhaps to be limited at 80hz. A lot of this likely has to do with the music I am generally listening to these days, which is not so busy in the mid range as say, rock and heavy vocal music.

I have been listening to it for a couple days now. CD Direct has made the biggest difference. Apparently, my ears don't care 'as much' for the coloration the AVR adds with it's built in tone controls.

Volume level is yet another. With the larger woofers of the mains, it sounds best turned up a little.

Part of this is because I do not understand the amp driving the sub yet. What each function of the DSP does. I am just getting into that. Hard to find any broad discussion on that without getting into movies. Just when I think I am onto something, I see "War of the Worlds" mentioned and I am back to square one. Just got into Parametric and Dynamic EQ and playing with the adjustments. I may be finally onto something here

It would be nice to be able to read something broken down more in laymen terms with regard to bass settings (like here, music heads, try this) other than how much technical mumbo jumbo one can possibly squeeze into a sentence, with the other extreme to that end basically translating to; "Bass dude Bass."

 

[PENG]

It would be nice to be able to read something broken down more in laymen terms with regard to bass settings (like here, music heads, try this) other than how much technical mumbo jumbo one can possibly squeeze into a sentence, with the other extreme to that end basically translating to; "Bass dude Bass."

Sorry if I missed something, since you mentioned stereo effects, do you have two subs already? If not, you can consider adding a second one of the same type, sit them as close to the L/R as possible and set crossover to the maximum available in your AVR. That would probably 200 hz if you have a Denon or Marantz.

 

[MrBoat]

Sorry if I missed something, since you mentioned stereo effects, do you have two subs already? If not, you can consider adding a second one of the same type, sit them as close to the L/R as possible and set crossover to the maximum available in your AVR. That would probably 200 hz if you have a Denon or Marantz.

I'm doing good with stereo. This is all just learning a more hands on approach like the 'olden days.' It seems as if everyone is afraid to go outside the automatic science and the broad generalizations. Not so much on this forum, mind you. I think here we get the best discussions in a most accommodating way. Across the net, and with the marketing itself, not so much.

I'm more or less looking for discussions of those who really get into the inner workings and settings of their equipment and capabilities beyond the hype and more so for music. In the meantime, I'm just trying things and either winning or failing at it but I'm getting there. IS also why I posted it in the beginner section because that's what I am, obviously.

 

[Pogre]

I'm doing good with stereo. This is all just learning a more hands on approach like the 'olden days.' It seems as if everyone is afraid to go outside the automatic science and the broad generalizations. Not so much on this forum, mind you. I think here we get the best discussions in a most accommodating way. Across the net, and with the marketing itself, not so much.

I'm more or less looking for discussions of those who really get into the inner workings and settings of their equipment and capabilities beyond the hype and more so for music. In the meantime, I'm just trying things and either winning or failing at it but I'm getting there. IS also why I posted it in the beginner section because that's what I am, obviously.

I'm still playing with settings, frequencies and placement. I'm starting to drive my wife crazy, lol. All I have right now is a spl app on my tablet and test tones from YouTube. Using that I've level matched fairly well, but have detected as much as 12db swings in some frequencies and can't seem to get a lot below 35-30 hz.

I really need to get a MiniDSP and a mic. Right now I'm probably just beating my head off a brick wall because I'm so limited with what I can do. I should be able to get the mic and mini in a week or 2. It's gonna drive me crazy until I do, even though it actually sounds pretty good. I have a little ocd and just knowing it can be better kills me.

 

[shadyJ]

Pogre, firstly, ignore frequencies below 18 Hz. Your subs aren't aren't really designed to play those frequencies, unless you set them in sealed mode. Also keep in mind that your tablet's microphone isn't very accurate at deep frequencies, so you don't know how well it is measuring very low frequency sound. I wouldn't give it much credibility below 30 Hz. For now, just get the subs to where they sound good, and let the tweaking wait till later, when you have some real tools to get the job done, ie a good calibration mic and software like REW.