Hi all,
comparatively ready 3 way speaker choices are limited (either expensive or one has to buy floorstander) So I was wondering...
1) what are technical disadvantages of having a bookshelf with subwoofer ?
2) If bookshelf measurements are available, can a passive crossover be made to match that bookshelf speaker with DIY passive subwoofer ?
3) (vague question) I know it depends on driver, speaker design and personal volume level preference, but what is very broad consensus on a typical 8 inch driver low end extension and levels achievable ?
thanks and regards.
comparatively ready 3 way speaker choices are limited (either expensive or one has to buy floorstander) So I was wondering...
1) what are technical disadvantages of having a bookshelf with subwoofer ?
2) If bookshelf measurements are available, can a passive crossover be made to match that bookshelf speaker with DIY passive subwoofer ?
3) (vague question) I know it depends on driver, speaker design and personal volume level preference, but what is very broad consensus on a typical 8 inch driver low end extension and levels achievable ?
thanks and regards.
The crossover to the subwoofer needs to be at a sufficiently low frequency that our 2 ears and a brain cannot locate the position of the subwoofer. This tends to occur somewhere around 50-60 Hz although 80 Hz has become a standard compromise with only a very minor cost in terms of low frequency imaging. If you cross higher at, say, 120 Hz then the low frequency imaging will be degraded more noticeably and it might be wise to position the sub between the speakers rather than where it performs best.
The required size of drivers to cleanly reproduce transients does not change and so using desktop 2.1 speakers in a room will mean the speakers cannot play cleanly at standard levels. For some this may not be an issue if they only listen quietly rather than at standard levels.
At low frequencies in the home a set of distributed subwoofers configured to control the room response is pretty much the only practical approach to achieving genuinely high sound quality in a shared space (i.e. not a room constructed like a studio). In this respect the use of subwoofers (typically 2-4 not 1) raises sound quality rather than reducing it.
Yes but it may be more expensive and/or lower quality depending on the details of the amplification, crossovers, cabinet loading of the mains,...
In a room that isn't large 2 way mains with 8" midwoofers and subs is a good budget configuration. Dropping in size to 6.5" midwoofers may ease the compromises in the tweeter/midrange crossover area but at the expense of those in the sub/midwoofer crossover area. It may be a better compromise if the listening levels are on the quieter side and the room small and/or you are sitting close at a desk.
If you are using subs the low end extension of the mains is relatively unimportant enabling the use of smaller sealed cabinets. What is important is the clean SPL the driver can reproduce for low frequency transients like percussion. This is primarily a question of size with the larger the better.
This is so easy to do with an active crossover and an extra amp that any alternative seems obtuse, and allows limitless playing with crossover frequency/slopes and EQ. The big trick is to high pass the bookshelf speakers to reduce excursion and to use as big a sub driver as possible - I wouldn't consider an 8" a 'sub'! Move a Lot of Air - GENTLY.
Hi,
I would add to what andy is saying : ready made bookshelves designed to make bass enough may be a problem according their roll off to add a sub. Try to find Troels Gravsen paper about that same question on his web site.
That's a trade off question and also room size related.
In most room a 8 or two 6.5" with low enough resonance suffice with the good load (forget sealed but if active). The said 80 hz cut off is a good targett, 100 hz is doable with sub between the bookshelves. Basicly, most of home rooms dictate the bass response below 200 to 300 hz. Try to look at the low end measurement of the bookshelf at -6 and - 12 dB to have a little idea of the bass box needs. But keep in mind at that frequencies drivers radiate omni, there is room gain, and room modes dictate the peaks and null of the power reponse.
Main problem is to model the low pass filter of the sub in order to gently cope to the low end roll off of the bookshelves. Best bet is an active sub. And the bookshelves bass low pass may be to be changed. Best bet again for minimal work but average result : 2 ways from PA studio with low end that can be setuped by pot or soft, KrK, Neumann, Adam, Genelec, etc. It migth be easier to marry with an active sub on which you can choose the cut-off, slope roll off, phase sometimes, and of course spl level. Average, not sota, but will work well enough with try and errors setup itterations.
Now do you really need it? What is the room size ?
Again a 8" in a TL or bass reflex may suffice. Or a simple 2.5 ways with two 6.5".
If diy cab is not an option look at pro studio bookshelves with their standalone sub cab as said by andy19191. Certa'inly good enough without spending a fortune with some brands like KrK or even Bheringer. Then focus with two ways with 4" to 6.5" driver.
Hope that helps.
I would add to what andy is saying : ready made bookshelves designed to make bass enough may be a problem according their roll off to add a sub. Try to find Troels Gravsen paper about that same question on his web site.
That's a trade off question and also room size related.
In most room a 8 or two 6.5" with low enough resonance suffice with the good load (forget sealed but if active). The said 80 hz cut off is a good targett, 100 hz is doable with sub between the bookshelves. Basicly, most of home rooms dictate the bass response below 200 to 300 hz. Try to look at the low end measurement of the bookshelf at -6 and - 12 dB to have a little idea of the bass box needs. But keep in mind at that frequencies drivers radiate omni, there is room gain, and room modes dictate the peaks and null of the power reponse.
Main problem is to model the low pass filter of the sub in order to gently cope to the low end roll off of the bookshelves. Best bet is an active sub. And the bookshelves bass low pass may be to be changed. Best bet again for minimal work but average result : 2 ways from PA studio with low end that can be setuped by pot or soft, KrK, Neumann, Adam, Genelec, etc. It migth be easier to marry with an active sub on which you can choose the cut-off, slope roll off, phase sometimes, and of course spl level. Average, not sota, but will work well enough with try and errors setup itterations.
Now do you really need it? What is the room size ?
Again a 8" in a TL or bass reflex may suffice. Or a simple 2.5 ways with two 6.5".
If diy cab is not an option look at pro studio bookshelves with their standalone sub cab as said by andy19191. Certa'inly good enough without spending a fortune with some brands like KrK or even Bheringer. Then focus with two ways with 4" to 6.5" driver.
Hope that helps.
Last edited:
When it comes to smaller speakers like bookshelves, it may be better to get a ready-made item. As already mentioned, the trick is in the crossing over frequency that needs to be as low as possible to sound non-localisable. It's very easy to get subwoofers for bookshelves that can seldom cross that low.
As a possible answer to (3), I have noticed several 1990s music systems having woofers that reach low enough for non-noticeable crossing to subs. You could get such a "blown" music system (several going around for peanuts) and modify it (if you want) and it should suffice for most indoor music applications. So, yes, there're 8" drivers that are quite capable but "pro" ones with datasheets etc. are usually more difficult to get than 12" or 15" drivers. Thus salvaging is key when it comes to such smaller drivers.
Examples (not mine):
https://www.carousell.ph/p/sony-90-s-stereo-component-1074078843/
As a possible answer to (3), I have noticed several 1990s music systems having woofers that reach low enough for non-noticeable crossing to subs. You could get such a "blown" music system (several going around for peanuts) and modify it (if you want) and it should suffice for most indoor music applications. So, yes, there're 8" drivers that are quite capable but "pro" ones with datasheets etc. are usually more difficult to get than 12" or 15" drivers. Thus salvaging is key when it comes to such smaller drivers.
Examples (not mine):
https://www.carousell.ph/p/sony-90-s-stereo-component-1074078843/
Using a subwoofer is all about ROOM INTEGRATION!
The position of the speaker to get an as uniform low frequency response as possible is never the position where your main speakers should be! So it's logical and beneficial to put these workloads in different speakers. But finding the right position and dial in the perfect level for a woofer is VERY hard to do without measurements - you end always with a way to loud woofer and then you can hear the position of it and it muddens and overlaps the sound.
Detection of directivity starts at a few hundred Hz for human ears. But you have to be sure the woofer is not producing sound in this area - so crossover at 80-100Hz os done very often. With a steeper crossover you can go higher.
When you have your sub level higher as your mains (and let's be honest - we all want more bass for some extra fun ;-)) it's a good idea to put the crossover frequencys a little appart, otherwise you get a hump in the crossover area. (well known in the PA world, but not often realised at home)
Be sure the sub is not making noises from the port or the chassis or electronics ... otherwise you will detect it's position.
And be careful - bookshelf speakers are MOSTLY not made to sit in a bookshelf! They are made and measured to sit on a stand with room around it, when you put them close to a wall frequency response changes a lot - they sound muddy, less "open". At least close the reflex port.
And last - ONE 8" river is not capable of showing the whole frequency range at a good listening level. But depending on your use case (music, home cinema, level) that'S probably not neccesary. But I would start with 10" or 2x 8"when integrating a woofer.
The position of the speaker to get an as uniform low frequency response as possible is never the position where your main speakers should be! So it's logical and beneficial to put these workloads in different speakers. But finding the right position and dial in the perfect level for a woofer is VERY hard to do without measurements - you end always with a way to loud woofer and then you can hear the position of it and it muddens and overlaps the sound.
Detection of directivity starts at a few hundred Hz for human ears. But you have to be sure the woofer is not producing sound in this area - so crossover at 80-100Hz os done very often. With a steeper crossover you can go higher.
When you have your sub level higher as your mains (and let's be honest - we all want more bass for some extra fun ;-)) it's a good idea to put the crossover frequencys a little appart, otherwise you get a hump in the crossover area. (well known in the PA world, but not often realised at home)
Be sure the sub is not making noises from the port or the chassis or electronics ... otherwise you will detect it's position.
And be careful - bookshelf speakers are MOSTLY not made to sit in a bookshelf! They are made and measured to sit on a stand with room around it, when you put them close to a wall frequency response changes a lot - they sound muddy, less "open". At least close the reflex port.
And last - ONE 8" river is not capable of showing the whole frequency range at a good listening level. But depending on your use case (music, home cinema, level) that'S probably not neccesary. But I would start with 10" or 2x 8"when integrating a woofer.
Couldn't you make two subs and stick the bookshelves on them? Perhaps make them with the same footprint and make them look like speaker stands. This would beg the question, do you have the sub driver at the top so it's close to the mid/bass of the bookshelf, or near the bottom to use the floor as a boundary.
Surely using bookshelves and sub/subs allows room matching of the bass (if they're driven by different amps) ?
I have used a larger pair of speakers to fill out the bass of smaller speakers by connecting them in parallel (they're both 8ohms) and using an inductor on the bigger speakers; ok, crude, but it worked.
Surely using bookshelves and sub/subs allows room matching of the bass (if they're driven by different amps) ?
I have used a larger pair of speakers to fill out the bass of smaller speakers by connecting them in parallel (they're both 8ohms) and using an inductor on the bigger speakers; ok, crude, but it worked.
Thanks everyone. all good critical points noted. compromised gist of all this will be (if one already has bookshelf or buying and adding sub later) to have atleast 10inch driver. crossover can be passive (expensive and needs proper implementation) or active.
another point I noted is most (not all) bookshelf will have port and if plugged the crossover fq. to sub will need to be higher than 80hz so a little compromise on localisation would be there.
for study purpose can anyone share a well implemented 2.5 way with 6.5 inch driver ? DIY or branded with measurement will be ok. Or some links would also be helpful.
best regard.
another point I noted is most (not all) bookshelf will have port and if plugged the crossover fq. to sub will need to be higher than 80hz so a little compromise on localisation would be there.
for study purpose can anyone share a well implemented 2.5 way with 6.5 inch driver ? DIY or branded with measurement will be ok. Or some links would also be helpful.
best regard.
I have some info about bookshelfs + sub on my pages, could be useful.
For passive integration you must be an expert in measureing and simulating speakers + crossovers. And you need to know how you will setup your speakers in the room and your choice of chassis is narrowed down a lot. So nobody is doing this for subwoofers (also - filters are usually more flat - problem!).
You can add a bass-socket to your speakers and cross over higher (3-400Hz) - this is something I would consider to do passive.
Active - best integration is like followed.
Close the reflex port of your speakers, measure the f3 frequency. Add a 2nd order high pass filter at the same frequency - now you have a nice filter 4th order.
Now you set a 4th order low pass for your woofer and you actually have a CHANCE to get a good phase transmission between woofer and speaker.
I then like to measure the transition woofer/speaker WITHOUT room to get that right first (outdoor, ground plane). With this as starting point I do the measurements in the room, find the best spot for the woofer(s) first and then get the correct delay for the listening position (tip - inverse phase of e.g. the woofer, set the delay for the biggest chancellation, get phase back -> best addition, best phase).
Like said before - without measurements it's impossible to make a perfect match between sub and main speakers. I bet most people who odon't like sub/sat systems never heard a proper set up - cause most people simply don't have a proper setup.
If you are not thinking "why did I bought this woofer, I can't hear it at all" until there is something serious happening in the bass area and you can't stop the smile in your face - your setup is not perfect ;-)
You can add a bass-socket to your speakers and cross over higher (3-400Hz) - this is something I would consider to do passive.
Active - best integration is like followed.
Close the reflex port of your speakers, measure the f3 frequency. Add a 2nd order high pass filter at the same frequency - now you have a nice filter 4th order.
Now you set a 4th order low pass for your woofer and you actually have a CHANCE to get a good phase transmission between woofer and speaker.
I then like to measure the transition woofer/speaker WITHOUT room to get that right first (outdoor, ground plane). With this as starting point I do the measurements in the room, find the best spot for the woofer(s) first and then get the correct delay for the listening position (tip - inverse phase of e.g. the woofer, set the delay for the biggest chancellation, get phase back -> best addition, best phase).
Like said before - without measurements it's impossible to make a perfect match between sub and main speakers. I bet most people who odon't like sub/sat systems never heard a proper set up - cause most people simply don't have a proper setup.
If you are not thinking "why did I bought this woofer, I can't hear it at all" until there is something serious happening in the bass area and you can't stop the smile in your face - your setup is not perfect ;-)
Hiten,
Some of these conventional wisdoms about subwoofer and satellite integration can be tested empirically for yourself. For instance the localisation of subwoofers depends on both the crossover (frequency) point, SPL and phase or group delay (how well they are matched in level and timing).
This is why when you buy and subwoofer and satellite, a level of fine tuning is required. It’s not as simple as rotating the knobs of the sub to same frequency as the satellite eg. both at X Hz (X being anywhere between 40 -160 Hz, typically) and calling it a day. The main challenge is that everyone’s speaker placement is different and every room is different, and the room affects, or controls, the frequency response, usually below 300-500Hz (Schroeder frequency)
So the challenge is, one has to be their audio expert. You have to set the volume levels, setting the crossovers, set the phase. And unless you have a great deal of experienc in doing this, or good ears, or ideally both, it’s very hard to get right! In live sound, it is professional job! (Front of House Engineer)
The advent of more affordable measurement equipment on the past 2 decades has made it easier, but it is still far from user friendly. The one that generally gives the most benefits with the least downsides is Dirac Live. Most other programs screw up the phase.
It’s been available to hardcore audio enthusiasts since about 2013 (maybe earlier, but that’s when I started using it). It requires a PC, and microphone, and some patience that you take about 9 measurements of your speakers throughout the room. It’s finally making its way into mainstream AV receivers eg. Marantz, Denon in 2023 as a standard feature, so after about 10 years, that’s a positive step.
On the other hand, when you buy a speaker with satisfying levels of deep bass (eg. 3 way or large 2 way; (and how large is large- well that depends on your room; an 8” 2-way may be too large my 2 bedroom 800 sq foot apartment in the city, but too small for a dedicated home theatre in a suburban home in North America) the crossover has been designed by the manufacturer. No more trying to get your subwoofer to marry your satellite.
The downside is that the best location for your speaker in terms of the lowest frequencies, may not be the best location for your middle frequencies, due to the wavelengths of sound involved.
So you just place it suits you and it might not sound the best. So you either accept it or go an adventure moving it about the room for better sound.
One of the best listening to check how well your speakers (with subwoofer or not) are positioned on your room are:
1. Subwoofer location test
https://www.audiocheck.net/audiotests_basslocalization.php
2. Low frequency test:
https://www.audiocheck.net/audiotests_frequencychecklow.php
Some of these conventional wisdoms about subwoofer and satellite integration can be tested empirically for yourself. For instance the localisation of subwoofers depends on both the crossover (frequency) point, SPL and phase or group delay (how well they are matched in level and timing).
This is why when you buy and subwoofer and satellite, a level of fine tuning is required. It’s not as simple as rotating the knobs of the sub to same frequency as the satellite eg. both at X Hz (X being anywhere between 40 -160 Hz, typically) and calling it a day. The main challenge is that everyone’s speaker placement is different and every room is different, and the room affects, or controls, the frequency response, usually below 300-500Hz (Schroeder frequency)
So the challenge is, one has to be their audio expert. You have to set the volume levels, setting the crossovers, set the phase. And unless you have a great deal of experienc in doing this, or good ears, or ideally both, it’s very hard to get right! In live sound, it is professional job! (Front of House Engineer)
The advent of more affordable measurement equipment on the past 2 decades has made it easier, but it is still far from user friendly. The one that generally gives the most benefits with the least downsides is Dirac Live. Most other programs screw up the phase.
It’s been available to hardcore audio enthusiasts since about 2013 (maybe earlier, but that’s when I started using it). It requires a PC, and microphone, and some patience that you take about 9 measurements of your speakers throughout the room. It’s finally making its way into mainstream AV receivers eg. Marantz, Denon in 2023 as a standard feature, so after about 10 years, that’s a positive step.
On the other hand, when you buy a speaker with satisfying levels of deep bass (eg. 3 way or large 2 way; (and how large is large- well that depends on your room; an 8” 2-way may be too large my 2 bedroom 800 sq foot apartment in the city, but too small for a dedicated home theatre in a suburban home in North America) the crossover has been designed by the manufacturer. No more trying to get your subwoofer to marry your satellite.
The downside is that the best location for your speaker in terms of the lowest frequencies, may not be the best location for your middle frequencies, due to the wavelengths of sound involved.
So you just place it suits you and it might not sound the best. So you either accept it or go an adventure moving it about the room for better sound.
One of the best listening to check how well your speakers (with subwoofer or not) are positioned on your room are:
1. Subwoofer location test
https://www.audiocheck.net/audiotests_basslocalization.php
2. Low frequency test:
https://www.audiocheck.net/audiotests_frequencychecklow.php
Last edited:
Sorry for late reply
mor generalised broad conclusion is having atleast 6.5 inch 2 way so one has choice of 80 to 120 hz crossover point and stuffing the port will make thng little bit easy.
thanks.
What is bass socket ? searched but can not find.
Yes IamJF, tktran303. I do understand without measurements speciall at low end with room involved it will be matter of chance that one likes the sound or not. room size and low frequencies required is also interesting other subject probably most important. Having low end driver separate from mains cab be of good help is what I never thought of.
mor generalised broad conclusion is having atleast 6.5 inch 2 way so one has choice of 80 to 120 hz crossover point and stuffing the port will make thng little bit easy.
thanks.
I use am additional active subwoofer with 12" woofer, not really the proper way it should be used. The main speakers are either Hedlund horns with Lowther DX2, Kef iQ3 or DIY Single Speaker Stereo box with 3x 3FE22. The speakers placement is different (SSS on the desk in front of me, KEFs on stands on the sides and the horns even further apart when I just listen and do not sit at the desk, the sub is below the desk as a compromised placement). I split the right channel before the main amplifier and use it to feed the sub set up by ear to somewhere between 60 and 80 Hz. Even with this not so optimal setup, I get enough low bass which seems to origin from the main speakers and not from the subwoofer.
I think active is the way to go, with mono bass and potentially more subs. I never finalized the setup properly for many resons, one of them being that the current one is good enough for the room and intended use.
I think active is the way to go, with mono bass and potentially more subs. I never finalized the setup properly for many resons, one of them being that the current one is good enough for the room and intended use.
"bass socket" - just use a woofer as speaker stand. You normally design this so it fits optically to the main speaker - narrow and high. If done right you could cross over at higher frequency, but of course you will loose the free positioning of an active sub woofer system.
It depends on your listening level how big the main speaker needs to be. I dislike the standard 6.5 inch 2 way cause of it's sound distribution pattern (you would need a waveguide or cross over <1,5kHz to get it even).
It depends on your listening level how big the main speaker needs to be. I dislike the standard 6.5 inch 2 way cause of it's sound distribution pattern (you would need a waveguide or cross over <1,5kHz to get it even).
some more general questions.
If one adds in 10 inch driver to a typical bookshelf speaker with port closed and with proper measurments a passive crossover, what happens to overall sensitivity of speaker system ? average impedance would be lower too ? As I see most amplifier having speaker A+B connection warns of not connecting more lower than 4 ohms speaker.
Thanks.
If one adds in 10 inch driver to a typical bookshelf speaker with port closed and with proper measurments a passive crossover, what happens to overall sensitivity of speaker system ? average impedance would be lower too ? As I see most amplifier having speaker A+B connection warns of not connecting more lower than 4 ohms speaker.
Thanks.
I do what many fullrange bookshelf speaker users do, a pair of 8" small and fast subs crossed high. Specifically, inexpensive Jamo SUB210 which has continuous phase knob (a must, turn until combined bass sounds fullest), flipped to face front as active "3rd-way". My "virtual" fullrange is 5" Monitor Audio Studio 2 (liter).