A Guide to Bass Management (Part I)

[Big Daddy]

Originally Posted by spaceape

I have been wondering about something.

If you have the lpf of lfe at 120Hz and the speaker crossovers at 80Hz won't that mean the speakers and the subwoofer will share some of the redirected sound (80hz-120hz)? Also won't the dedicated lfe channel and the redirected bass from the speakers get mixed up somehow?

All the information in the LFE channel below 120Hz goes to the subwoofer. If you set the crossover of the speakers at 80Hz, the speakers only reproduce what is directed to them. None of the information from the LFE channel will go to the speakers. If you do not have a subwoofer, the front speakers will automatically be set to LARGE and the LFE information will go to the front speakers. The audio engineer really determines what information goes to the LFE channel and what goes to the speakers.

The information that comes out of the subwoofer is the combined redirected bass from the speakers plus the information that goes to the LFE channel. You should check the diagrams in Post #1.

[derrickdj1]

Big Daddy I am purchasing an epik legend sub 12 in. and want to use it with my AA 15in sub. I know it is perferred to use two identical subs. Which sub to place in the corner. I will use an spl meter to set the subs to 73 db and then run MCACC on my Pioneer avr to re-set speaker level. Any other advice. I could not find anything in you guides on setting up two non-identical subs. I currently use to different subs with no phase or other problem. So I have been able to achieve good room intergration.

[Big Daddy]

Originally Posted by derrickdj1

Big Daddy I am purchasing an epik legend sub 12 in. and want to use it with my AA 15in sub. I know it is perferred to use two identical subs. Which sub to place in the corner. I will use an spl meter to set the subs to 73 db and then run MCACC on my Pioneer avr to re-set speaker level. Any other advice. I could not find anything in you guides on setting up two non-identical subs. I currently use to different subs with no phase or other problem. So I have been able to achieve good room intergration.

I have eight external subwoofers in my home theater room. Almost all of them are different and most of them are passive and are powered by external amplifiers. This is in addition to two 15" powered subwoofers built in my front speakers. Setting up so many subwoofer and adjusting their levels is a full-time job for crazy people. I have changed their position and upgraded their drivers and/or their amps so many times that I have lost count. No woder why my back hurts most of the time.

Setting up different subwoofers is no different than setting up identical subwoofers. It may take more time adjusting their levels or positioning them in the room. Just make sure their levels are approximately the same in the listening area. As far as positioning one in the front and one in the rear, there is no clear cut answer. Each room is different and you need to experiment. If you decide to put the subwoofers in the corners of the room, don't place them too close to the side walls as they may become too boomy. Raising them by puting they on a riser may help their performace.

[derrickdj1]

I think I have them intergrated into the room pretty well. I level matched them and neither one is able to be localized. I was careful not to run the AA sub hot. The epik sub is unusual due to the opposing divers being located on the sides. ? which way to face the sub? Is the Behringer worth considering to help draw out the under 25Hz sounds or just go with it if it sounds good? Thank for you help

[Show spoiler]

[Big Daddy]

Originally Posted by derrickdj1

I think I have them intergrated into the room pretty well. I level matched them and neither one is able to be localized. I was careful not to run the AA sub hot. The epik sub is unusual due to the opposing divers being located on the sides. ? which way to face the sub? Is the Behringer worth considering to help draw out the under 25Hz sounds or just go with it if it sounds good? Thank for you help

[Show spoiler]

As far as facing the Epik sub, you need to experiment and decide which way it sounds the best to you.

If you are talking about the Behringer equalizer, it is a good option if your receiver does not have a good built-in auto calibration program such as Audyssey. If the auto calibration program inside your receiver is pretty basic, then it may worth investing in the Behringer and the Room Equlization Wizard (REW). However, using them is not quite as easy as the using an auto calibration program.

[Sithlord75]

Do I still leave the crossover on my sub set at max, even after I've set my receiver to 80hz ?? Or should I turn it down to 3/4 setting ?

[Big Daddy]

Originally Posted by Sithlord75

Do I still leave the crossover on my sub set at max, even after I've set my receiver to 80hz ?? Or should I turn it down to 3/4 setting ?

New AV receivers do all the bass management. You should turn the crossover dial on the back of the subwoofer all the way up. A crossover of 80Hz is appropriate for most speakers. However, if your receiver offers a separate crossover setting for the subwoofer, you should set it to 120Hz. The reason is because the LFE (.1) channel has information up to 120Hz. If you set the subwoofer crossover in the receiver to 80Hz, you will throw out any information between 80Hz and 120Hz that may exist in the LFE (.1) channel.

[Sithlord75]

Originally Posted by Big Daddy

New AV receivers do all the bass management. You should turn the crossover dial on the back of the subwoofer all the way up. A crossover of 80Hz is appropriate for most speakers. However, if your receiver offers a separate crossover setting for the subwoofer, you should set it to 120Hz. The reason is because the LFE (.1) channel has information up to 120Hz. If you set the subwoofer crossover in the receiver to 80Hz, you will throw out any information between 80Hz and 120Hz that may exist in the LFE (.1) channel.

Yeah, my receiver will let me set the crossover for the sub. I'll adjust it to 120hz.

Thanks Big Daddy.

[JOMV]

BD!!!!

I have some questions about the settings I should use when calibrating my speakers. I have read about 3 different ways to do it and I a little confused.

Here is a list of my speakers and their frequency responses.

*** My front speakers are 3-way (3 feet tall) towers and each of them have one 8" woofer. The manual for my towers shows a FR of 45Hz - 20Khz. And according to all that I have read on your threads, I have 3 options:

(Option A) - I remember reading almost everywhere that the speakers should be set at 80Hz.

(Option B) - On one of your threads you recommended to set the frequency from 10hz - 15Hz above the minimum capacity.

(Option C) - According to the first table you posted on this thread, I should set them to 60.

So, this leaves me with the following possible settings according to each of those options:

Option A = 80Hz
Option B = 55Hz or 60Hz
Option C = 60Hz (very close to option #B)

1) Which one do you recommend???

2) Do I have to consider the center speaker before I decide???

3) Or, are they independent one from the other??


*** My Center Speaker has two 6.5" woofers. The manual for my center speaker shows a FR of 60Hz - 20Khz.

The following are my possible settings according to each of the presented options:

Option A = 80Hz
Option B = 70Hz or 75Hz
Option C = 60Hz (because it has two 6.5" woofers)

Which one do you recommend???


*** My Surrounds/Height Speakers have one 5" woofer. The manual for those speakers shows a FR of 85Hz - 20Khz.

Again, the following are my possible settings according to each of the presented options:

Option A = 80Hz
Option B = 95Hz or 100Hz
Option C = 100Hz

Which one do you recommend???


The subwoofer is the only one that has been already set: (No Need to Discuss this one because you already helped me with this one)
FR = 38Hz - 150Hz

- Setting at Subwoofer = 150Hz
- Setting at Receiver = 120Hz

I'm getting my knees ready for the subwoofer crawl!!!

Thanks again, BD!!!

[Big Daddy]

JOMV,

You are misunderstanding what I said in Post #1 and taking those statements out of context. Let me clarify.

1. As a general rule, a crossover frequency of 80Hz is a good starting point for most speakers. I explained the origin of 80Hz in A Guide to Bass Management (Part II).
2. Make sure that the crossover of 80Hz or whatever frequency you choose is at leaset 10Hz to 20Hz above the low frequency extension of the speakers.
3. If the you are using very small satellite type of speakers and their low frequency extension is 100Hz, you should not set the crossover to 80Hz.
4. Even if the low frequency extension of your front speakers is 40Hz, a crossover frequency of 80Hz is appropriate. It is normally best to redirect the lower frequencies below 80Hz to the strategically placed subwoofer(s).
5. If you cannot find any information about the frequency response of your speakers, consult the tables at the beginning of A Guide to Bass Management (Part I) as a starting point to make sure that, for example, a crossover frequency of 80Hz is above the low frequency extension of the speakers.

Going back to your specific questions.

1. If your receiver allows you to set only one crossover frequency that applies to all the speakers, then a crossover of 90Hz to 100Hz may be appropriate to make sure your surround speakers are not over extended.
2. If your receiver allows you to set separate crossover frequencies for each speaker, then choose 80Hz for the front speakers and 90Hz to 100Hz for the surround speakers.

[JOMV]

Originally Posted by Big Daddy

JOMV,

You are misunderstanding what I said in Post #1 and taking those statements out of context. Let me clarify.

1. As a general rule, a crossover frequency of 80Hz is a good starting point for most speakers. I explained the origin of 80Hz in A Guide to Bass Management (Part II).
2. Make sure that the crossover of 80Hz or whatever frequency you choose is at leaset 10Hz to 20Hz above the low frequency extension of the speakers.
3. If the you are using very small satellite type of speakers and their low frequency extension is 100Hz, you should not set the crossover to 80Hz.
4. Even if the low frequency extension of your front speakers is 40Hz, a crossover frequency of 80Hz is appropriate. It is normally best to redirecut the lower frequencies below 80Hz to the strategically placed subwoofer(s).
5. If you cannot find any information about the frequency response of your speakers, consult the tables at the beginning of A Guide to Bass Management (Part I) as a starting point to make sure that, for example, a crossover frequency of 80Hz is above the low frequency extension of the speakers.

Going back to your specific questions.

1. If your receiver allows you to set only one crossover frequency that applies to all the speakers, then a crossover of 90Hz to 100Hz may be appropriate to make sure your surround speakers are not over extended.
2. If your receiver allows you to set separate crossover frequencies for each speaker, then choose 80Hz for the front speakers and 90Hz to 100Hz for the surround speakers.

Thanks, BD!!!. Clearly, this speaker thing is not my specialty (hi-tech weapons are) . I just retired from the NAVY, and I'm trying to get a normal life. I knew I was more than confused with so many speaker/combination stuff. I believe my receiver allows to set the speakers individually (Denon AVR-2312ci). I haven't installed it yet, but I made some research last night and found this specifications list http://www.audio-net.com.ar/denonavr2312.htm

Please, correct my once again if I'm wrong again!

Your help is much appreciated!!!

Ps.
I started buying stuff since I first read one if your threads...... And now, my wife is starting to hate you!!!

[Big Daddy]

Originally Posted by JOMV

Thanks, BD!!!. Clearly, this speaker thing is not my specialty (hi-tech weapons are) . I just retired from the NAVY, and I'm trying to get a normal life. I knew I was more than confused with so many speaker/combination stuff. I believe my receiver allows to set the speakers individually (Denon AVR-2312ci). I haven't installed it yet, but I made some research last night and found this specifications list http://www.audio-net.com.ar/denonavr2312.htm

Please, correct my once again if I'm wrong again!

Your help is much appreciated!!!

Ps.
I started buying stuff since I first read one if your threads...... And now, my wife is starting to hate you!!!

I believe your receiver allows you to set the crossover frequencies of all the speakers independently. It may be a good idea to run Audyssey first. Audyssey will set the level and frequency response of each speakers. If you decide to modify these crossover frequencies, make sure you set them avove the numbers Audyssey chose. You should not lower them below Audyssey's numbers.

Your wife is not the only who hates me. I am hated by almost all the wives because I encouraged their husbands to speant too much money on their HT gear. Wait until your wife sees my bill, then she will really hate me.

[wes]

Hello Big Daddy,

Thank you, I have a question, will raising a sub-woofer improve the sound and why

[Big Daddy]

Originally Posted by wes

Hello Big Daddy,

Thank you, I have a question, will raising a sub-woofer improve the sound and why

Check Posts #2 and #3 of the DIY Subwoofer Risers thread.

[jsnmoussa80]

hello everybody. This is my first post on this site. I am fairly new to audio . Ihad a system when i was younger but it was very amatuer and i didnt even know what calibration was. Sorry to jump straight into this problem but i dont know what to do. This is my system so far

FRONTS. Monitor audios gx100
centre. pretty cheap accusound
rears . cambridge audio minx 21. Which for their size sound really sweet.
denon 2312 amp
svs pb12 plus sub
Now this is my issue. I had a REL T9 sub before the svs. When i first hooked it up using just the lfe it sounded so nice when watching terminator salvation. The only issue with the sub i had was that when it came to massive bass , in a way it would kinda bottom out. The sub was on floor boards. So i got a sub dude hd. WOW what a difference it made. Anyway i wanted more and lower htz so i got the svs. Also i live in australia and to be honest we dont have those top brands that they have in America. The best brand we have here are Velodyne. the dd12 + is really nice. I got the svs , but should have researched it more because this thing is MASSIVE. But it is too big for my room 3 meters by 4 meters. The bass is so boomy amd muddy even after calibrating it using audussey. I have foam tiles on the wall but doesnt do much for this sub. I am now trying to sell it and get the REL 328 instead. Please any suggestions would be really appreciated and sorry for the long post.would a eq such as the sms1 solve the issue for me or would it be better just to sell and get a smaller box. you guys seem to know what you are talking about.

[Big Daddy]

Originally Posted by jsnmoussa80

hello everybody. This is my first post on this site. I am fairly new to audio . Ihad a system when i was younger but it was very amatuer and i didnt even know what calibration was. Sorry to jump straight into this problem but i dont know what to do. This is my system so far

FRONTS. Monitor audios gx100
centre. pretty cheap accusound
rears . cambridge audio minx 21. Which for their size sound really sweet.
denon 2312 amp
svs pb12 plus sub
Now this is my issue. I had a REL T9 sub before the svs. When i first hooked it up using just the lfe it sounded so nice when watching terminator salvation. The only issue with the sub i had was that when it came to massive bass , in a way it would kinda bottom out. The sub was on floor boards. So i got a sub dude hd. WOW what a difference it made. Anyway i wanted more and lower htz so i got the svs. Also i live in australia and to be honest we dont have those top brands that they have in America. The best brand we have here are Velodyne. the dd12 + is really nice. I got the svs , but should have researched it more because this thing is MASSIVE. But it is too big for my room 3 meters by 4 meters. The bass is so boomy amd muddy even after calibrating it using audussey. I have foam tiles on the wall but doesnt do much for this sub. I am now trying to sell it and get the REL 328 instead. Please any suggestions would be really appreciated and sorry for the long post.would a eq such as the sms1 solve the issue for me or would it be better just to sell and get a smaller box. you guys seem to know what you are talking about.

Equalization should always be the last resort in fixing problems with a subwoofer's performance. You should primarily concern yourself about placement and setting up your subwoofer before you perform equaliztion. The location of your subwoofer in the room creates the standing wave modes. And the modes are what determine whether your listening position gets great bass or poor bass. If your chair or sofa happens to be located in one of the troughs of the standing waves, you are not going to hear much deep bass. But if you get up and walk a few feet back, or to the left, or to the right, chances are you will hit one of the peaks and the bass will be very strong, perhaps too much of a good thing. An equalizer will solve some problems, primarily those related to peaks. A null is an entirely different situation and no amount of boost can fill a room-induced null. Think of it as a water drain. No amount of water can fill a drain.

These are my suggestions

1. If your subwoofer is too loud and boomy, move it away from the side walls.
   1. A subwoofer in the corner of the room energizes all room modes and will be very loud.
   2. If you place a subwoofer in the middle of a rectangular room, chances are that all waves will cancel each other and you will hear no bass.
   3. Similarly, the location of your listening chair in the room determines how loud the bass will be. If you sit too close to the walls, the bass will be too loud and boomy.
2. Regular foam on the walls will help with reflections of high frequency waves, but they are totally ineffective when it comes to low frequency waves coming out of a subwoofer. Bass traps are a lot more effective. Using multiple bass traps in the room can help, but they are expensive.
3. If you put the subwoofer on a riser, it may help its performance. You can build one yourself.
4. On the back of the subwoofer, turn its volume down to 50% or less.
5. On the back of the subwoofer, turn the crossover dial all the way up to take it out of the picture.
6. After you do the initial placement and settings, run Audyssey again. If the Audyssey in your receiver allows the microphone to be placed in multiple positions, do it.
7. After calibration, make sure the low pass filter (crossover) of the subwoofer in the receiver's menu is set to 120Hz.

If placement of the subwoofer, adjusting the location of your listening chair, and calibration do not help, you may consider buying a Subsonic Filter to block the ultra low frequencies from your subwoofer. After all, your room is pretty small and you don't want to create earthquakes.

Harrison Labs sells inexpensive subsonic filters. They also have an Ebay store.

Harrison Labs:
http://store.hlabs.com/

Ebay Store:
http://www.ebay.com/sch/i.html?_nkw=harrison+labs

[derrickdj1]

I was hoping you were still monitoring this thread. Great! I have a simple question, a lot of people try to cut the gain up think that it will make the sub louder. But, in a balance HT with Auddysee they are just cutting the preamp signal? A given sub will have a max. spl and playing with the gain is just alerting the voltage to get to the max. spl. A -10 setting in the avr mean that the preamp has to send out a higher voltage signal?

[Big Daddy]

Originally Posted by derrickdj1

I was hoping you were still monitoring this thread. Great! I have a simple question, a lot of people try to cut the gain up think that it will make the sub louder. But, in a balance HT with Auddysee they are just cutting the preamp signal? A given sub will have a max. spl and playing with the gain is just alerting the voltage to get to the max. spl. A -10 setting in the avr mean that the preamp has to send out a higher voltage signal?

I am not sure I fully understand your post.

1. When people cut (lower) the gain, they do not expect the subwoofer to become louder. They cut the gain to make the subwoofer’s level lower.
2. If Audyssey sets the subwoofer’s gain in the AVR to -10dB, it normally means the microphone has detected that the bass sound in the listening area is too loud. That is why it has tried to lower the bass level as much as possible.
3. The -10dB setting in many AVRs is the lowest possible level. When this level is set by the calibration program it is signalling you to lower the gain on the back of the subwoofer. If you lower the gain on the back of the subwoofer and run the calibration program, it is possible that the gain in the receiver may be set around -5dB or -6dB. Those levels are generally preferred to a setting such as -10dB that may be the absolute largest negative setting.
4. In some situations, the calibration programs such as Audyssey may increase the gain in the AVR to a positive number. That is done mainly because the microphone has detected that the bass level is too low in the listening area.
5. The other factor beside playing with gains to increase or decrease the level of the subwoofer is its location. Moving the subwoofer to different areas of the room can make a difference. For example, a subwoofer in the corner of the room energizes all room modes and will be the loudest. Similarly, if you sit against the wall, the bass will be too loud.
6. It is also a mistake to assume people have a single subwoofer in the room. More and more people are learning about the benefits of having multiple subwoofers in their rooms. When you have multiple subwoofers scattered around the room, the calibration microphone picks up the total bass sound coming out of all the subwoofers. That is why it may be a good idea to calibrate the level of each subwoofer first and then calibrate the total level of all subwoofers combined together.
7. Ultimately, the gain numbers are not the important factors. You want to make sure that the total bass level in the listening area is around 75 dBs. At the same time, it is important to make sure that none of the subwoofers in the room are overextended.

[derrickdj1]

Thanks for taking the time to answer my post. I was thinking more along the line of what is going on with the preamp signal with high and low gain setting. I know either way the sub max spl is fixed. A gain of -10 will cut the preamp signal and a gain of + 10 will increase the preamp signal. I was just checking make sure I understood that concept correctly. I follow you post on making some sub risers. They turned out great.

[Korrigan]

Hello,

my "cheap" Pioneer VSX-322 amplifier only has 50, 80, 100, 150 and 200 settings for X-OVER, no 120 setting.

What would you recommend? I use to have it at 100 since that's the lowest frequency on the specifications of my "small" speakers, but should I put it on 150 to avoid losing some LFE info?

From what I understood, the X-OVER setting in the amplifier does not affect the LFE channel, but only filters out too low frequency sounds from the other channels. Even if set at 100, the amplifier will filter out anything lower than 100 from the "small" speakers, but the LFE channel from e.g. a Blu-Ray HD audio track will be sent unchanged to the subwoofer. Am I right here?

Thanks.