Subwoofer integration - Bookshelf vs Tower Speakers

[gurujee]

I have general doubt in the scenario of - integrating a subwoofer with 2 channel speaker set up with stereo amplifier with a sub-out, without any bass management option in the amp and without using any EQ or DSPs etc

I am reading quite a bit about this in the forum and outside.

Read at many places that in the above scenario integrating a bookshelf with sub is easier than integrating a tower. Probably because Bookshelf speaker generally has frequency response from 60hz, hence crossover on subwoofer can be set at around 60 to have an overlap of just 10hz, thus subwoofer will have a breathing room from 20hz to 60hz and both speaker/subwoofer can do their duty optimally without interfering much. But in case of towers which generally have frequency response from 40hz, crossover on subwoofer if set at 60hz will have 20 hz overlapping causing cancellation of duplicate frequencies and creating either muddy sound or a vacuum in the the 40-60hz regions; if crossover on subwoofer set at 40hz, then the sub with frequency response from 30/35hz won't have a breathing region and sound restricted. In the above scenario, does room size also play a role?

Is the above observation right?

If yes, then a newbie like me should keep an eye while purchasing stuffs - he should decide first whether he is going to add subwoofer or not. And choose stuff accordingly. He should buy

• Subwoofer with frequency response starting from 20hz
• Bookshelf Speaker with frequency response 60hz or above above

or

• Tower speaker/Bookshelf which can go as low as possible and no subwoofer

Doubt: If someone already got a subwoofer that responds from 35hz and tower/bookshelf that responds from 40hz, will bound to be doomed while setting up with an integrated stereo amplifier. Am I right?

Sorry, if I am sounding foolish. Sound and science is not my forte. I am trying to understand these things.

 

[Analogous]

I have general doubt in the scenario of - integrating a subwoofer with 2 channel speaker set up with stereo amplifier with a sub-out, without any bass management option in the amp and without using any EQ or DSPs etc

I am reading quite a bit about this in the forum and outside.

Read at many places that in the above scenario integrating a bookshelf with sub is easier than integrating a tower. Probably because Bookshelf speaker generally has frequency response from 60hz, hence crossover on subwoofer can be set at around 60 to have an overlap of just 10hz, thus subwoofer will have a breathing room from 20hz to 60hz and both speaker/subwoofer can do their duty optimally without interfering much. But in case of towers which generally have frequency response from 40hz, crossover on subwoofer if set at 60hz will have 20 hz overlapping causing cancellation of duplicate frequencies and creating either muddy sound or a vacuum in the the 40-60hz regions; if crossover on subwoofer set at 40hz, then the sub with frequency response from 30/35hz won't have a breathing region and sound restricted. In the above scenario, does room size also play a role?

Is the above observation right?

If yes, then a newbie like me should keep an eye while purchasing stuffs - he should decide first whether he is going to add subwoofer or not. And choose stuff accordingly. He should buy

• Subwoofer with frequency response starting from 20hz
• Bookshelf Speaker with frequency response 60hz or above above

or

• Tower speaker/Bookshelf which can go as low as possible and no subwoofer

Doubt: If someone already got a subwoofer that responds from 35hz and tower/bookshelf that responds from 40hz, will bound to be doomed while setting up with an integrated stereo amplifier. Am I right?

Sorry, if I am sounding foolish. Sound and science is not my forte. I am trying to understand these things.

Hi, we were all newbies at one time, and I suspect many like me are partially informed enthusiasts, who continue to learn.

Of all the components in the audio chain, I found the lowest 20hz (20-40hz) reproduction the most challenging and most rewarding. Getting this right takes some time, effort but once you get it close to right, you can not live without it.
Researching and choosing the right sub in terms of SQ, matching, and budget are going to take time and effort.
Learning about how low frequency sound waves behave in your room, understanding standing waves, and doing the Subwoofer crawl to get it integrated into your set up and locked in are all other exiting chapters in this journey.
But I repeat once you experience good quality bass you can not live without it. Pity many listeners hear boomy bass and give up on subwoofers too soon.

Here is well known audio reviewer John Darko who after many years of ignorance finally discovers the joy of a subwoofer!

 

[Analogous]

I have both bookshelves and towers integrated with a sub. The sub definitely adds low end quantity and quality with both, when integrated well (crossover, gain, position)

 

[Analogous]

In case you want to start with understanding what some commonly used terms mean, here is one that is “frequently used: “Frequency Response” . I found this very informative.

Understanding Frequency Response - Why it Matters

Search the Alesis Knowledge Base for any immediate support needs.

www.alesis.com

 

[gurujee]

oh..thanks so much for replying. I will go through both the video and article and try to get the doubts cleared. Thank you again

 

[Hiten]

Read at many places that in the above scenario integrating a bookshelf with sub is easier than integrating a tower. Probably because Bookshelf speaker generally has frequency response from 60hz, hence crossover on subwoofer can be set at around 60 to have an overlap of just 10hz, thus subwoofer will have a breathing room from 20hz to 60hz and both speaker/subwoofer can do their duty optimally without interfering much. But in case of towers which generally have frequency response from 40hz, crossover on subwoofer if set at 60hz will have 20 hz overlapping causing cancellation of duplicate frequencies and creating either muddy sound or a vacuum in the the 40-60hz regions; if crossover on subwoofer set at 40hz, then the sub with frequency response from 30/35hz won't have a breathing region and sound restricted. In the above scenario, does room size also play a role?

In my limited understanding, Integrating subwoofer requires some work in both given specification wise and by listening. Lots will depend on how steep the low end on bookshelf or floor standers will be. Which you call overlap and breathing room. In a room the low frequencies will have dips and peaks any way which you probably mention as duplicate and cancellation. Even full frequency band speakers will have that too. (Unless room is treated and response measured and equalized to somewhat tame this)
In my unexperienced (armchair) thinking if you want good clean low end purchase speakers that go low and take advice on room treatment/placement etc. from expert. Dont aim for too much accurate reproduction.
Subwoofer may have advantage though, which is you can switch off for simple vocal music etc.
choices...choices...
Regards.

 

[Analogous]

Here is an old thread (lots of love for REL subs) with interesting and useful information on Subwoofers in general too:
https://www.hifivision.com/threads/...integrated-into-your-2-ch-or-ht-system.75534/

 

[gurujee]

In my limited understanding, Integrating subwoofer requires some work in both given specification wise and by listening. Lots will depend on how steep the low end on bookshelf or floor standers will be. Which you call overlap and breathing room. In a room the low frequencies will have dips and peaks any way which you probably mention as duplicate and cancellation. Even full frequency band speakers will have that too. (Unless room is treated and response measured and equalized to somewhat tame this)
In my unexperienced (armchair) thinking if you want good clean low end purchase speakers that go low and take advice on room treatment/placement etc. from expert. Dont aim for too much accurate reproduction.
Subwoofer may have advantage though, which is you can switch off for simple vocal music etc.
choices...choices...
Regards.

Thank you. This is a great suggestion.

 

[Doomster69]

Plenty of insights already offered.. il give a few suggestions from my hands on experience.. (im no expert, just learning).. a few points to think about..

1. The most important area for sub integration is correcting for room modes. To do this appropriately, start with the correct speaker placement (there is a good youtube video by new record day on this, and i have experienced it works with some minor tweaks by ear). Then the sub integration by subwoofer crawl around the room. In my experience, while DIRAC,YPOA, etc. DSPs will give you a good set up, it still needs to be tweaked by your 'ears' - The worlds best DSPs, tuned to each individual

2. Usually if you connect the speakers with sub using high level speaker inputs, that manages the output levels, regulating the signal in equitable manner to both speakers and sub/subs. The subs sample the signal and do their bit thereon.

3. Apart from crossover cut-off, 'phase' is equally important. An out of phase subwoofer with speakers (despite being set at the right cross over) may muddy the bass or make it sound overpowering. Unless use DSP, the best way to do the phase correction is 'by ear'. There is no fixed measure to this as every room is different (bringing on room mode) and will also be impacted by sub positioning in the room. A good way to really test where your speakers drop off (and not what the seller says on the box) is to run a low level frequency sweep. You will actually see and hear where the speakers actually cut-off - this test is also important because the speakers low frequency outputs vary with amp pairings and may not always match the rated low freq. cited by speaker manufacturer. In some brands, you may see the low freq. extend beyond the rated specs and vice versa. So, best to test.

4. The speaker output volume levels on the subwoofer will also matter to a great extent. For stereo listening, the subs should be blended in with the speakers and by no means should you be able to localize the bass. In my experience, keeping the sub slightly below the cut off crossover frequencies and lower volume output tends to give a better sounding bass impact. Idea is to let your bookshelves breathe from higher sub-bass, mid-bass onwards and not let the sub output creep into mid bass region. You will hear the negative impact of excess bass as the speakers become less revealing/airy and sound bit bloated/ excessively thumpy.

5. To pt. 4 above - in case of a 2.1 home theatre set up, you my increase the vol on your sub by 2-3 notches to give rumble and punchy impact in the lower level freq., making for a satisfying content watching experience. When u go back to stereo, all you do is bring down the volume 2-3 notches.

6. Another good way to test the sub output is do a speaker A/B test where speaker A is your BS/tower and B is the sub. In some AVRs/AMPs, you can connect 2 pairs of speakers and this can be done quite easily. If you have connected both speakers to same terminal, then simply ask someone to help you turn it on and off to assess the impact. The idea again is to be blend than have either stand out on their own - as music and content changes, you will find imperfect blending literally jumping at you.

7. If you have dual subs, the above approaches work well upto a certain pt. Since sub freq. is omnidirectional, nulls are difficult to spot by ear, and you have 2 subwoofers doing their magic, DSP based correction is always advised for optimal tuning (beyond what ears can hear). Good youtube ref. videos online on sub integration using MiniDSP and U-mic for this.

8. When integrating with tower speakers, you must assess how much sound pressure can the towers create w.r.t thump. Ideally if the room is fairly larger (more than 15ft x 12 ft), you may want to keep the cross over between towers and subwoofer on the higher end (80 hz ideal). That lets the sub pressurise the room well enough to give you omnidirectional bass impact while towers bring in the directional impact of bass/sub-bass. However, for a small room, better to keep the crossover lower (like say 40 Hz). Here is an interesting fact that literally changed my understanding - generally i believed the bass impact from subwoofer is really in the sub 50-80Hz range. While this is mostly true as the subwoofer adds more that sound band than any other, most heavy impacts from effects (gunshots, explosions are in the 100 Hz - 200 Hz range. For instance, there is a video on youtube where one measures the sub's impact - in the movie The Accountant, there is a scene where the protagonist (Ben Affleck) is firing shots from a long range sniper rifle. The main thump from the bullet shot is actually observed to be in 100hz - 200 Hz range and the after shot rumble comes in further down in freq. range. Yes, when Godzilla steps on something, the sub does alot of heavy lifting.

9. Usually people buy towers to be able to get the deeper bass impact - see any BS and Tower of the same speaker brand, usually the extra drivers are to produce more bass while the mids and high freq. drivers remain the same. So in effect, in a tower speaker set up, the use of a subwoofer is somewhat 'limited' to filling in the 'lowest of the lows'. Contrarily, in bookshelf set up, the subwoofer really does most of the low end reproduction ( heavy lifting) to "fill out" the mid bass and sub bass regions. For instance, you can get a pair of Sonos Fabre Bookshelves/Harbeth Bookshelf speakers (read good mids and highs) and pair it with well blended dual subs (like REL/SVS). I would hazard a wager that these can sound much more pleasant than an equally expensive set of full range tower speakers. The rule of thumb for me - when you need larger room filling sound, towers work better. But for average sized indian household rooms, bookshelves + subs work much better, eliminating the technical difficulties of controlling bass! I saw a pair of Triangle BR-08 towers listed by an FM simply because they were too much for his space!


10. Lastly, If the integration is done well, here you should still not be able to really localize the bass and yet feel the weight of the bass impact. Bass should be felt more than it can be heard, especially if its a sub putting out the signal. Quoting Paul S Barton - if you are able to localize the sub and point out where it is, you have 'lost the plot'.


Good luck integrating the sub!

 

[gurujee]

Plenty of insights already offered.. il give a few suggestions from my hands on experience.. (im no expert, just learning).. a few points to think about..

1. The most important area for sub integration is correcting for room modes. To do this appropriately, start with the correct speaker placement (there is a good youtube video by new record day on this, and i have experienced it works with some minor tweaks by ear). Then the sub integration by subwoofer crawl around the room. In my experience, while DIRAC,YPOA, etc. DSPs will give you a good set up, it still needs to be tweaked by your 'ears' - The worlds best DSPs, tuned to each individual

2. Usually if you connect the speakers with sub using high level speaker inputs, that manages the output levels, regulating the signal in equitable manner to both speakers and sub/subs. The subs sample the signal and do their bit thereon.

3. Apart from crossover cut-off, 'phase' is equally important. An out of phase subwoofer with speakers (despite being set at the right cross over) may muddy the bass or make it sound overpowering. Unless use DSP, the best way to do the phase correction is 'by ear'. There is no fixed measure to this as every room is different (bringing on room mode) and will also be impacted by sub positioning in the room. A good way to really test where your speakers drop off (and not what the seller says on the box) is to run a low level frequency sweep. You will actually see and hear where the speakers actually cut-off - this test is also important because the speakers low frequency outputs vary with amp pairings and may not always match the rated low freq. cited by speaker manufacturer. In some brands, you may see the low freq. extend beyond the rated specs and vice versa. So, best to test.

4. The speaker output volume levels on the subwoofer will also matter to a great extent. For stereo listening, the subs should be blended in with the speakers and by no means should you be able to localize the bass. In my experience, keeping the sub slightly below the cut off crossover frequencies and lower volume output tends to give a better sounding bass impact. Idea is to let your bookshelves breathe from higher sub-bass, mid-bass onwards and not let the sub output creep into mid bass region. You will hear the negative impact of excess bass as the speakers become less revealing/airy and sound bit bloated/ excessively thumpy.

5. To pt. 4 above - in case of a 2.1 home theatre set up, you my increase the vol on your sub by 2-3 notches to give rumble and punchy impact in the lower level freq., making for a satisfying content watching experience. When u go back to stereo, all you do is bring down the volume 2-3 notches.

6. Another good way to test the sub output is do a speaker A/B test where speaker A is your BS/tower and B is the sub. In some AVRs/AMPs, you can connect 2 pairs of speakers and this can be done quite easily. If you have connected both speakers to same terminal, then simply ask someone to help you turn it on and off to assess the impact. The idea again is to be blend than have either stand out on their own - as music and content changes, you will find imperfect blending literally jumping at you.

7. If you have dual subs, the above approaches work well upto a certain pt. Since sub freq. is omnidirectional, nulls are difficult to spot by ear, and you have 2 subwoofers doing their magic, DSP based correction is always advised for optimal tuning (beyond what ears can hear). Good youtube ref. videos online on sub integration using MiniDSP and U-mic for this.

8. When integrating with tower speakers, you must assess how much sound pressure can the towers create w.r.t thump. Ideally if the room is fairly larger (more than 15ft x 12 ft), you may want to keep the cross over between towers and subwoofer on the higher end (80 hz ideal). That lets the sub pressurise the room well enough to give you omnidirectional bass impact while towers bring in the directional impact of bass/sub-bass. However, for a small room, better to keep the crossover lower (like say 40 Hz). Here is an interesting fact that literally changed my understanding - generally i believed the bass impact from subwoofer is really in the sub 50-80Hz range. While this is mostly true as the subwoofer adds more that sound band than any other, most heavy impacts from effects (gunshots, explosions are in the 100 Hz - 200 Hz range. For instance, there is a video on youtube where one measures the sub's impact - in the movie The Accountant, there is a scene where the protagonist (Ben Affleck) is firing shots from a long range sniper rifle. The main thump from the bullet shot is actually observed to be in 100hz - 200 Hz range and the after shot rumble comes in further down in freq. range. Yes, when Godzilla steps on something, the sub does alot of heavy lifting.

9. If the integration is done well, here you should still not be able to really localize the bass and yet feel the weight of the bass impact. Bass should be felt more than it can be heard, especially if its a sub putting out the signal. Quoting Paul S Barton - if you are able to localize the sub and point out where it is, you have 'lost the plot'.


Good luck integrating the sub!

Really grateful for this help. I will follow the guide and let know. Thanks so much for this extensive write up.

 

[Doomster69]

Doubt: If someone already got a subwoofer that responds from 35hz and tower/bookshelf that responds from 40hz, will bound to be doomed while setting up with an integrated stereo amplifier. Am I right?

Sorry, if I am sounding foolish. Sound and science is not my forte. I am trying to understand these things.

Not doomed but yes will take some trial and error to find that optimal balance..As i mentioned, alot will depend on room size (activating room modes), speaker placement and fine tuning. It can be done - if one is willing to accept that the sub will only work in very narrow band of low frequencies. In my experience, you can make bookshelves also sound big and impactful by activating the room modes (i.e. how the speakers react to your room). My pair of Elac B5 bookshelves are set in a way to do just that in a 12 by 10 room. Sometimes the my wife comes to complain that i need to turn the sub down wherein i point out to her that the sub is off and she leaves speechless

Remember, there are no foolish questions, just foolish answers (from the likes of me )

 

[gurujee]

Not doomed but yes will take some trial and error to find that optimal balance..As i mentioned, alot will depend on room size (activating room modes), speaker placement and fine tuning. It can be done - if one is willing to accept that the sub will only work in very narrow band of low frequencies. In my experience, you can make bookshelves also sound big and impactful by activating the room modes (i.e. how the speakers react to your room). My pair of Elac B5 bookshelves are set in a way to do just that in a 12 by 10 room. Sometimes the my wife comes to complain that i need to turn the sub down wherein i point out to her that the sub is off and she leaves speechless

Remember, there are no foolish questions, just foolish answers (from the likes of me )

ha ha... ha.. this is really inspiring. thanks for the help. I think I have lots of homework for this weekend.

 

[cooltoad]

Get 2 subs and you will be happy with very little tweaking.

 

[gurujee]

Found this on another forum. Seems my guess was right?

Adding a Sub to a Stereo system is easier if the Front speaker have a slightly higher rated low end. Most Sub can only be set at about 45hz. For the best blend of Front and Sub, you want to set the Sub at the rated roll-off of the Front speakers. But if you Front Speaker are rated down below 40hz, you can't really do this. So, when blended with a Sub, the higher rate low end response is actually an advantage, because it lets you blend the speakers in the working range of the Sub Crossover Control.

Of course, with an AV Receiver, this is not a problem because the Receiver has its own built-in Electronic Bass Management. But in a Stereo, this is a critical factor.

 

[Doomster69]

Why guess when you can try for yourself. Just takes a bit of time and patience. If you cant do it, get a minidsp.

 

[gurujee]

Why guess when you can try for yourself. Just takes a bit of time and patience. If you cant do it, get a minidsp.

Thank you. Actually I am on the work following your and others suggestions. Thing is I have no any other speakers other than the towers. Will order a bookshelf for the stereo setup and conclude the experiment.

 

[Doomster69]

Here is an informative video on how to use a minidsp..I did the same when integrating the 2 subs with the HT also being used as main 2.2 channel audio.

 

[Doomster69]

Thank you. Actually I am on the work following your and others suggestions. Thing is I have no any other speakers other than the towers. Will order a bookshelf for the stereo setup and conclude the experiment.

pm me..happy to help with what ever i know..with exact details of gear, room etc.

 

[Doomster69]

My set up in a 10x8 ft rooms (pretty bad shape for acoustics, yet works very well with all tweaks) with following speakers and specs

Main L+R - PSB X2T TOWERS..they go pretty low and have a very low freq. cutoff (see specs).

Frequency Response​

On Axis @ 0° ±3dB	30-23,000Hz
On Axis @ 0° ±1 1/2dB	40-20,000Hz
Off Axis @ 30° ±1 1/2dB	45-10,000Hz
LF Cutoff -10dB	28Hz

A centre channel with specs below..again goes down to 50hz which is audible/felt

Frequency Response​

On Axis @ 0° ±3dB	50 - 23,000Hz
On Axis @ 0° ±1 1/2dB	65 - 20,000Hz
Off Axis @ 30° ±1 1/2dB	65 - 10,000Hz
LF Cutoff -10dB	45Hz

A pair of surrounds - PSB Alpha P5. which as just a stereo pair can go down pretty low 40 hz audible/felt

Frequency Response​

On Axis @ 0° ±3dB	55-21,000Hz
On Axis @ 0° ±1 1/2dB	65-20,000Hz
Off Axis @ 30° ±1 1/2dB	65-10,000Hz
LF Cutoff -10dB	37Hz

And 2 SVS Subs that go down to 19hz (not audible, felt in gut) all the way to 270 hz

The 5.1 set up is AVR controlled and thats alot of palpable range of bass for a small room with 2 bass traps. So what you read about AVRs doing it correct (not a guess). Even the AVR DSP works on 4 basic principles of distance, timing, phase and crossover. However, i have set up a 2.1 set up (PSB Towers and 1 subs) just using the method suggested in earlier comments/ without the minidsp or AVR!

It can be done with a pair of towers and one sub. So you can do it with the present gear, dont have buy Bookshelves

 

[gurujee]

pm me..happy to help with what ever i know..with exact details of gear, room etc.

Thanks so much. Saw it now. Thanks so much for helping out.. was away from forum for a while.. and meanwhile got a bookshelf QA3030i. Yet to set up. will do in the weekends.