Dual Sub setup question

[SPH]

How do you do this? run speaker wire out of one and then into the other?

Originally Posted by jibucha

Hello

Definitely, proper set up, is having one subwoofer per channel.

This way, whatever sound information is available, whether left or right, is left or right, as intended; you will hear the difference.

Thank You

[jibucha]

Hello

Placement of subwoofers, hopefully, needs to be in close proximity to the loudspeakers, as well as the best tested location in the room taking careful measurements, for the best room and system frequency response. Together, the result will be a coherent sound throughout, including clear and powerful low frequencies.

From your photograph, your subwoofers are in a good beginning location.

Probably, moving them about a foot sideways from the fireplace and about two feet from the rear wall, will get you very close to the best balance of the two important considerations of coherency and proper bass performance.

The overview issues, are coherency, flat frequency response, crossover point, sensitivity/gain balance, and location. Properly balancing these fundamentals is required for the best system performance.

Thank You

[aramis109]

Originally Posted by jibucha

Hello

Definitely, measure separately.

Remember, to make certain that your connections are separate left and right, from the receiver or amplifer, to each appropriate subwoofer, again left or right.

While many on this thread have indicated preferences; only individual runs is proper for proper performance.

The issues become quite involved, so I am intentionally keeping this to be as direct and simple as possible, as the outcome is simply to hook up subwoofers as you would loudspeakers, with left and right individual.

Nothing changes just because it is a subwoofer; after all, subwoofers are simply an extension of the loudspeaker itself.

Properly setting a system up, maintains proper performance, especially the left and right balance, for the most coherent sound throughout, including the frequency range of the system.

Thank You

What are you talking about- left and right balance with a subwoofer? It's a mono signal typically coming out of one output. It doesn't matter how you split it, it's not going to suddenly be in stereo. The only exception to this would be subs built-in to a front speaker that are getting a typical front left/front right signal. Unless I'm missing something, not only is sound from 80hz non-directional, LFE information is a mono signal.

[jibucha]

Hello

This is as simple, as how you already hookup up loudspeakers.

The difference depends entirely on the output and input options of your equipment.

Do you have a receiver or power amplifier; I just want to be certain of the connection options?

Just keep in mind though, that wiring left and right separately from your power source is extremely important, whether commonly recognized or not.

Question; are these powered subwoofers? I only just realized this is unknown to me.

Actually, either directly send me photographs of the connections of your receiver, which I assume you are using, and the subwoofer.

This way, I can accurately determine the proper wiring for you, and be clear, avoiding any mistakes by either of us; ok?

You can post here if you like as well, as I seem caught up in following this progress this afternoon.

I look forward to hearing from you at your convenience.

Thank You

Originally Posted by SPH

How do you do this? run speaker wire out of one and then into the other?

[aramis109]

Ah, that answers my question. Don't wire it like this if you have a powered sub- you'll end up having to set up the crossover points for both the sub and the front speakers, as well as distances, level calibrations/etc. The benefit of having a left/right signal in this case is non-existant since again, LFE is uni-directional, and you won't be able to tell where the sound is coming from if your system is set up properly. You'd be better off using an RG6 RCA cable with the subwoofer pre-out/LFE out output.

[SPH]

Originally Posted by aramis109

Ah, that answers my question. Don't wire it like this if you have a powered sub- you'll end up having to set up the crossover points for both the sub and the front speakers, as well as distances, level calibrations/etc. The benefit of having a left/right signal in this case is non-existant since again, LFE is uni-directional, and you won't be able to tell where the sound is coming from if your system is set up properly. You'd be better off using an RG6 RCA cable with the subwoofer pre-out/LFE out output.

Thats why I asked. I only have out from the amp side of my subs..I will leave it alone

[jibucha]

Hello

I knew this was coming; and, I am prepared - what a wonderful day.

While the issues of frequency and localization, that you refer to are commonly known; the more critical information of the human ear's sensitivily to SPL differencies at low frequencis is unfortunately not, and it is far more important.

Those informed, know this, fully realizing from experience with high quality sound systems and high quality subwoofers, if not, from reliable engineering and physics sources.

Remember, on the internet, anything is possible. But, in science, the truth and facts are just the truth and facts, being just reliable science.

Myself, it only took twenty minutes, many years ago, with some rather remarkable subwoofers. Even without two subwoofers, I realized that the sound system with just one was seriously askew and immediatly ordered a second subwoofer to repair the sound field to the system. With two properly set up, the system balance was restored and extended, as expected, with remarkable improvement to everything, which I enjoy and appreciate ever since.

Many years later, discussing this in detail with a very knowledgeable electircal engineer; the details of it all were taught to me; finally.

So; this is simple, and more importantly, does matter.

Thank You

Originally Posted by aramis109

What are you talking about- left and right balance with a subwoofer? It's a mono signal typically coming out of one output. It doesn't matter how you split it, it's not going to suddenly be in stereo. The only exception to this would be subs built-in to a front speaker that are getting a typical front left/front right signal. Unless I'm missing something, not only is sound from 80hz non-directional, LFE information is a mono signal.

[jibucha]

Hello

There is so much confusion, I wonder if this can be done at all.

Everyone; experiment!

Proper integration, left and right, with the loudspeakers, is always the proper implementation, using two subwoofers.

Using and LFE, or low frequency effects speaker- subwoofer; would only be implemented in conjunction with either satellite speakers and subwoofers, or loudspeakers and subwoofers, for further extension and authority.

However, an LFE, is only after the primary sound system is already set up properly.

Subwoofers is one thing and LFE is another thing, as is and understanding of the connections and performance options of the equipment used.

Thank You

Originally Posted by aramis109

What are you talking about- left and right balance with a subwoofer? It's a mono signal typically coming out of one output. It doesn't matter how you split it, it's not going to suddenly be in stereo. The only exception to this would be subs built-in to a front speaker that are getting a typical front left/front right signal. Unless I'm missing something, not only is sound from 80hz non-directional, LFE information is a mono signal.

[aramis109]

Originally Posted by jibucha

Hello

I knew this was coming; and, I am prepared - what a wonderful day.

While the issues of frequency and localization, that you refer to are commonly known; the more critical information of the human ear's sensitivily to SPL differencies at low frequencis is unfortunately not, and it is far more important.

Those informed, know this, fully realizing from experience with high quality sound systems and high quality subwoofers, if not, from reliable engineering and physics sources.

Remember, on the internet, anything is possible. But, in science, the truth and facts are just the truth and facts, being just reliable science.

Myself, it only took twenty minutes, many years ago, with some rather remarkable subwoofers. Even without two subwoofers, I realized that the sound system with just one was seriously askew and immediatly ordered a second subwoofer to repair the sound field to the system. With two properly set up, the system balance was restored and extended, as expected, with remarkable improvement to everything, which I enjoy and appreciate ever since.

Many years later, discussing this in detail with a very knowledgeable electircal engineer; the details of it all were taught to me; finally.

So; this is simple, and more importantly, does matter.

Thank You

The sound field "repair" you're discussing is more of a point of standing waves/room correction. Every system doesn't "need" two subwoofers to adequately balance the system. What I think you were talking about doing was running speaker wire from the front l/r of the receiver to your subs, and then running from the subs to your fronts. Again, the issue with that is that the receiver/pre-amp processor basically sees them as "one" speaker and you cannot set up separate crossover points/distances/trim and boost levels/SPL levels. It's a limitation that I can't understand introducing into the system. Perhaps you can share the science behind it with some concrete links/quotes because I'm not seeing it.

[Driver_King]

Jibucha, I will try to clear this up, if I understand you correctly. Having a subwoofer connected to each of your front speakers is what you are talking about (using the binding posts on the subwoofer and using the subwoofer amplifier and crossover network to increase the bass output), similar to Definitive Technology's Super Tower speakers with built-in subwoofers, but not exactly. You are also trying to explain the difference between LFE (the .1 of a surround sound system and soundtrack) and using subwoofers to add to your existing speakers since there are low frequency effects that are sent to your speakers as well. Is this correct jibucha?

[Driver_King]

Originally Posted by aramis109

The sound field "repair" you're discussing is more of a point of standing waves/room correction. Every system doesn't "need" two subwoofers to adequately balance the system. What I think you were talking about doing was running speaker wire from the front l/r of the receiver to your subs, and then running from the subs to your fronts. Again, the issue with that is that the receiver/pre-amp processor basically sees them as "one" speaker and you cannot set up separate crossover points/distances/trim and boost levels/SPL levels. It's a limitation that I can't understand introducing into the system. Perhaps you can share the science behind it with some concrete links/quotes because I'm not seeing it.

This is what he is talking about. Think of it as an extra driver you are adding to your current speakers, like a super-tweeter. Some subwoofers come with their own calibration systems like Velodyne. In fact, Velodyne sells their Digital Drive calibration system separately to control multiple subs and do room calibrations and act as a standalone calibration system.

[PurpleJesus74]

Originally Posted by DavidAg02

This article should answer all your questions about using multiple subs:

http://www.audioholics.com/tweaks/ge...nnection-guide

Thats a great article,thanks for posting it.Sounds like one of the best positions is having a sub at the front and back wall,which is what i'm thinking about doing.

[aramis109]

Originally Posted by Driver_King

This is what he is talking about. Think of it as an extra driver you are adding to your current speakers, like a super-tweeter. Some subwoofers come with their own calibration systems like Velodyne. In fact, Velodyne sells their Digital Drive calibration system separately to control multiple subs and do room calibrations and act as a standalone calibration system.

No, I understand the concept, just not the reasoning behind it. Your distances will be off. The trim/boost levels will be lumped together. You won't be able to set a low pass filter at all. You're more limited in placement of your 2nd sub. Your sub is now what's driving your fronts, rather than your receiver/amp. And the end benefit is that you're getting "stereo sound" from something that most folks can't perceive directionality for? Woot, sign me up!

[jibucha]

Hello

I appreciate your effort here; thank you.

Let me try to simply the overview.

LFE l It is an adjunct for special effects, to be implemented after the main speaker system is properly implemented, with low frequencies well supported with large and powerful bass drivers whether part of the loudspeaker or with subwoofers. It works at extremely low frequencies and will not be coherent with satellite speakers unless already properly supported with subwoofers, due to a significant discontinuity between satellite speakers and LFE crossover frequencies, that a proper implementation of subwoofers will support.

Subwoofers & Loudspeakers l Most loudspeakers are seriously deficient in low frequency performance, when judged against the potential performance of subwoofers at low frequencies. This is why subwoofers are so engaging, especially with regards to home theater systems and Blu-ray playback.

Yes; subwoofers in conjunction with either full range loudspeakers or limited range satellite speakers is the basic setup. However, the connectivity of this arrangement varies considerably, depending entirely on the system components and what they selectively allow. So, generalizing with regards to connections would be impossible.

Typically, crossover points of 60Hz to 80Hz is ideal, but components may require higher crossover points to compensate for limitations of the system components.

"You are also trying to explain the difference between LFE (the .1 of a surround sound system and soundtrack) and using subwoofers to add to your existing speakers since there are low frequency effects that are sent to your speakers as well."

Essentially, yes; however, the varying connectivity of the electronics and loudspeakers differ considerably.

Additionally, satellite speakers would inherently require the use of subwoofers to deliver the basic required frequency range, which is also common to most full range loudspeakers. Both though, require subwoofers for the lowest octaves and output for the SPL levels expected from Blu-ray Systems for convincing performance.

What I am trying to make very clear, is that two subwoofers, in conjunction with whatever loudspeakers used, whether small or large, being satellite or full range, are required before an LFE is used.

Yes; an LFE is also a subwoofer, but at this very low frequency range, in conjunction with two other subwoofers [meaning three subwoofers for the system], is the basic framework for performance.

Proper set up, in conjunction with the available options and performance of the system components, will dictate the resulting performance.

While set up is the term for setting up the system, as calibration is the term for calibrating a display; it is comprehensible that it is a system calibration that I am referring to, but the same term is not normally used in the industry.

I wish that I had more available time, but I have much to do and have already spent considerable time here today.

I sincerely hope that this is becoming clear, and that I have not contributed to the confusion today.

I will try to come back to this and follow through, should it be helpful.

Thank You

Originally Posted by Driver_King

Jibucha, I will try to clear this up, if I understand you correctly. Having a subwoofer connected to each of your front speakers is what you are talking about (using the binding posts on the subwoofer and using the subwoofer amplifier and crossover network to increase the bass output), similar to Definitive Technology's Super Tower speakers with built-in subwoofers, but not exactly. You are also trying to explain the difference between LFE (the .1 of a surround sound system and soundtrack) and using subwoofers to add to your existing speakers since there are low frequency effects that are sent to your speakers as well. Is this correct jibucha?

[Big Daddy]

jibucha,

What you are suggesting is old news. There was a time in the 1980's when people started discussing and discovering stereo subwoofers. I remember reading a few articles about the benefits of stereo subs in some audio magazines. That was one of the reasons I bought two subwoofers back then.

The problem back then was that almost all subwoofers were passive and had a fixed crossover around 120Hz to 240Hz. My old DBX subwoofer worked like that. Also the vast majority of receivers/preamps were stereo. Not too many people had heard about powered subwoofers.

Typically, you would connect the the speaker wires from the receiver to the subwoofer and then use speaker wires to connect the subwoofer to the speakers. The crossover inside the sub took care of the primitive bass management. I had a set of German speakers like that in 1978-1979 as a young audio nut.

By mid 1980's there was some discussion of stereo subs. Obviously, with a crossover above 120Hz, it made some sense. By late 1980s, a few places like Dak Industries started advertising a relatively new product called subwoofer amplifiers with their own built-in crossovers that enhanced the performance of a subwoofer. We had not heard the term powered subwoofer back then. I bought two different models of DBX sub amp in 1990-1991. Currently, I use one to power a DIY subwoofer in my two-channel room. The other one is picking dust in one of the closets.

Starting in early to mid 1990's, after the introduction of Dolby Digital, receiver manufactures slowly started introducing basic bass management and LFE. Unfortunately, many people are confused about LFE.

Modern sound engineers create a low frequency effect to make their movies more realistic. Even if you have 5 super large speakers, you should still have s subwoofer for the LFE signal. Without a subwoofer, the LFE signal is directed to the front speakers and that creates two problems:

1. The speakers may not be able to handle the low frequency sound.
2. You lose the flexibility of experimenting with the position of the sub as you cannot move the front speakers to the side or to the rear. The long wavelengths of bass sound interact wih the room boundaries and create standing waves. You need to be able to move the subwoofer around the room to find the optimal position.

The second function of a subwoofer is to assist the other speakers that do not have good low frequency extension. We call this bass management by directing bass frequencies from smaller speakers to the subwoofer.

With proper placement in a room, one subwoofer can give reasonable bass sound for one listening position. However, if you move a couple of feet in either direction, the bass sound may be terrible. The solution is a second subwoofer. Although some people erroneously assume that the purpose of a second subwoofer is to increase the level of bass sound, that is not the real reason. With two subwoofers, you will have more flexibility in placement in order to reduce the effect of room modes and get a more even and smoother bass sound across the room for all listening positions.

Extensive research by Dr. Toole and his associates at the National Research Council of Canada and at Harmon International have demonstrated that the ideal number is 4 subwoofers. In their demonstrations, they have shown that more than 4 subwoofers do not benefit you as much. Remember the law of diminishing returns.

If you want to add more subwoofers to the speakers in addition to the LFE subwoofers, you can do that.

[jibucha]

Hello

No; none of what I previously indicated has anything to do with room set up issues or room acoustics, rather with the fundamentals of audio performance characteristics of a properly designed and set up system; focusing on why.

Yes; without exception, two subwoofers in conjunction with the loudspeakers, are always required. One subwoofer alone is always a serious compromise. If you, or anyone for that matter disagrees, I suggest that you properly set up a system both ways and it will be quite obvious. Anyone with two subwoofer properly set up can set up a single subwoofer and I categorically guarantee that none will disagree.

In closing, you are refering in your closing to system factors, being the equipment used, and whatever limitations that the system components dictate. Knowing what is required, and purchasing the proper components and performance, makes the set up the simple task that it hardly ever is, but should always be.

Regarding reference sources; know well of Velodyne, I would think that contacting Velodyne would be my recommendation for a good start. They have been designing some of the most outstanding subwoofers for decades now, and their technical support should be able to confirm what I have been indicating today. Additionally, as an alternative, perhaps some of their manuals for their subwoofers, should have supporting information for my posts today as well - Good Luck.

Thank You

Originally Posted by aramis109

The sound field "repair" you're discussing is more of a point of standing waves/room correction. Every system doesn't "need" two subwoofers to adequately balance the system. What I think you were talking about doing was running speaker wire from the front l/r of the receiver to your subs, and then running from the subs to your fronts. Again, the issue with that is that the receiver/pre-amp processor basically sees them as "one" speaker and you cannot set up separate crossover points/distances/trim and boost levels/SPL levels. It's a limitation that I can't understand introducing into the system. Perhaps you can share the science behind it with some concrete links/quotes because I'm not seeing it.

[jibucha]

Hello

Yes; old news, which with regards to audio, is accurate news, however, I have never used crossover points above 80Hz and have always used state of the art high performance subwoofers with a cost of thousands of dollars. All of what I have imparted is by experience and an understanding of how things work; certainly not from reading of others thoughts and opinions.

My points hold firm, and apply.

Regretfully, we disagree in several areas; what more can I say? Especially with regards to LFE and subwoofers in general.

With all my posts today, it should be clear without me detailing it again here.

Importantly though, a properly selected system will facilitate proper set up, which would be quite straight forward to those knowledgeable in set up.

Dr. Floyd Toole would certainly be a reference in this regard, but to imply that he would contradict would be erroneous.

Velodyne additionally, would be and excellent reference.

Thank You

Originally Posted by Big Daddy

jibucha,

What you are suggesting is old news. There was a time in the 1980's when people started discussing and discovering stereo subwoofers. I remember reading a few articles about the benefits of stereo subs in some audio magazines. That was one of the reasons I bought two subwoofers back then.

The problem back then was that almost all subwoofers were passive and had a fixed crossover around 120Hz to 240Hz. My old DBX subwoofer worked like that. Also the vast majority of receivers/preamps were stereo. Not too many people had heard about powered subwoofers.

Typically, you would connect the the speaker wires from the receiver to the subwoofer and then use speaker wires to connect the subwoofer to the speakers. The crossover inside the sub took care of the primitive bass management. I had a set of German speakers like that in 1978-1979 as a young audio nut.

By mid 1980's there was some discussion of stereo subs. Obviously, with a crossover above 120Hz, it made some sense. By late 1980s, a few places like Dak Industries started advertising a relatively new product called subwoofer amplifiers with their own built-in crossovers that enhanced the performance of a subwoofer. We had not heard the term powered subwoofer back then. I bought two different models of DBX sub amp in 1990-1991. Currently, I use one to power a DIY subwoofer in my two-channel room. The other one is picking dust in one of the closets.

Starting in early to mid 1990's, after the introduction of Dolby Digital, receiver manufactures slowly started introducing basic bass management and LFE. Unfortunately, many people are confused about LFE.

Modern sound engineers create a low frequency effect to make their movies more realistic. Even if you have 5 super large speakers, you should still have s subwoofer for the LFE signal. Without a subwoofer, the LFE signal is directed to the front speakers and that creates two problems:

1. The speakers may not be able to handle the low frequency sound.
2. You lose the flexibility of experimenting with the position of the sub as you cannot move the front speakers to the side or to the rear. The long wavelengths of bass sound interact wih the room boundaries and create standing waves. You need to be able to move the subwoofer around the room to find the optimal position.

The second function of a subwoofer is to assist the other speakers that do not have good low frequency extension. We call this bass management by directing bass frequencies from smaller speakers to the subwoofer.

With proper placement in a room, one subwoofer can give reasonable bass sound for one listening position. However, if you move a couple of feet in either direction, the bass sound may be terrible. The solution is a second subwoofer. Although some people erroneously assume that the purpose of a second subwoofer is to increase the level of bass sound, that is not the real reason. With two subwoofers, you will have more flexibility in placement in order to reduce the effect of room modes and get a more even and smoother bass sound across the room for all listening positions.

Extensive research by Dr. Toole and his associates at the National Research Council of Canada and at Harmon International have demonstrated that the ideal number is 4 subwoofers. In their demonstrations, they have shown that more than 4 subwoofers do not benefit you as much. Remember the law of diminishing returns.

If you want to add more subwoofers to the speakers in addition to the LFE subwoofers, you can do that.

[aramis109]

Have you ever had a friend, or teacher, try to use big words in an attempt to impress you and appear intelligent, yet never really string them together in a cognizant manner? I have, and that's what I feel is happening here. You're trying so hard to sound intelligent that the meaning of what you're trying to get across is lost. It's not that I don't understand the words; I do. It's that they're not really saying anything. It's almost like technical babble in an attempt to overwhelm someone with less knowledge.

I'm sorry, but you seem to either be operating under old knowledge, as BD has more tactfully implied, or maybe things are being lost in communication. In my opinion though, none of what you've stated has made any sense. I'll just finish up my part in the conversation and say that dual subwoofers can help to even out bass response for more of the room; to kill off any dead areas in the room, and to improve the overall frequency response. They're not used to create a stereoscopic effect with LFE.

[jibucha]

Hello

I guess that you are right after all; nothing technical here.

From your post, I have failed miserably at trying to keep it simple and non-technical; clearly I did not do well.

For this my apology.

It would take several months of difficult work to create a Guide to Subwoofers; regretfully, I cannot undertake this task. Today I did my best, but certainly we agree that it was not helpful, which after all, was the purpose for the person that created this thread.

While I do wish that I could continue, regretfully I have to decline, as it is just not that important to me to continue on with the confusion; especially as much of it now is less than technical, which is the foundation of AV Systems.

Thank You

Originally Posted by aramis109

Have you ever had a friend, or teacher, try to use big words in an attempt to impress you and appear intelligent, yet never really string them together in a cognizant manner? I have, and that's what I feel is happening here. You're trying so hard to sound intelligent that the meaning of what you're trying to get across is lost. It's not that I don't understand the words; I do. It's that they're not really saying anything. It's almost like technical babble in an attempt to overwhelm someone with less knowledge.

I'm sorry, but you seem to either be operating under old knowledge, as BD has more tactfully implied, or maybe things are being lost in communication. In my opinion though, none of what you've stated has made any sense. I'll just finish up my part in the conversation and say that dual subwoofers can help to even out bass response for more of the room; to kill off any dead areas in the room, and to improve the overall frequency response. They're not used to create a stereoscopic effect with LFE.

[kndy]

Hehe...anyone watch the comedy sitcom "The Big Bang Theory"...about the physicists who are always trying to challenge each other's perspective?

Nevertheless, good comments on the technical end of components and soundwaves and on the practical end based on years of experience using multiple subwoofers and varying points on setting up dual subwoofers.