Hi,
I'm asking about the best ratio under 100 hz and room size ?
Why ? I listened many speakers in domestic rooms (20 to 35 m²... sorry for inches) . Some of the speakers I heard have great bass result with -3 db at 50 hz ! and some speakers with 30 or 35 hz - 3 db have less punch !
I think that the curve between 100 and 80 hz is very imprtant for bass impact...but just an idea !
But in another way I surmise that sub harmonics in ledium an high end are imprtant for bass impact ?
So, I have 2 questions : how to set up the low pass for bass driver in a three way speaker in relation to the room (any ratio ?)
And what about, the mid and treble for the feeling of bass impact (any good ratio ? Iso curve, or else ?)
Feel free to tell if the question seems stupid... (but some speaker with less low end make more bass ! My idea : 60 to 100 hz are a vital area ! and a bumps between 80 to 100 is a good thing for speakers in most of domestical rooms)
I'm asking about the best ratio under 100 hz and room size ?
Why ? I listened many speakers in domestic rooms (20 to 35 m²... sorry for inches) . Some of the speakers I heard have great bass result with -3 db at 50 hz ! and some speakers with 30 or 35 hz - 3 db have less punch !
I think that the curve between 100 and 80 hz is very imprtant for bass impact...but just an idea !
But in another way I surmise that sub harmonics in ledium an high end are imprtant for bass impact ?
So, I have 2 questions : how to set up the low pass for bass driver in a three way speaker in relation to the room (any ratio ?)
And what about, the mid and treble for the feeling of bass impact (any good ratio ? Iso curve, or else ?)
Feel free to tell if the question seems stupid... (but some speaker with less low end make more bass ! My idea : 60 to 100 hz are a vital area ! and a bumps between 80 to 100 is a good thing for speakers in most of domestical rooms)
For Room Modes modulation and evaluation, some links.
Evaluation of recordings
Room Mode Simulator
http://www.diyaudio.com/forums/multi-way/241449-new-program-room-response-simulation.html
Evaluation of recordings
Room Mode Simulator
http://www.diyaudio.com/forums/multi-way/241449-new-program-room-response-simulation.html
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What you are seeing is very common. Smaller speakers if built right, generally do not have much bass. That is precisely why they don't throw Rock Concerts with 5" bookshelf speakers. But there is a trick the makers of bookshelf speakers use. To create the sense of bass, the create a bass bump in the Bass Presence range.
That is precisely the range you spoke of. I had some very low cost speaker, Sony 5" bookshelf with rated bass at 80hz, but they still sounded like they had very good bass. But perception is not reality. The sounded like they had good bass, but they didn't.
Now, the same trick can be applied to cheaper floorstanding speakers too. The put a big bass bump in, young men are impressed. They buy the speakers.
But, in better floorstanding, and bookshelf too, you don't want to be fooled, quite the opposite, you want reproduction as close as possible to what is contained on the Medium (vinyl records, CDs, etc...). Therefore these better speakers don't have over-amp, hyper, droning, exaggerated bass. But they sound stunning. And I have hear very very expensive very clear speaker that initially didn't seem to have any bass until I realized I could feel it slamming into my body. It was rendered perfectly, or as perfectly as $4000/pr speaker can.
There are other tricks as well. If you want to give the illusion of great life and presence to speaker, you simply build in an upper midrange bump.
But to a finely tuned ear, all these 'Tricks' get tiring after a while.
So, don't confuse perception with reality. It is easy to create perception in speaker, with out actually delivering on the thing that is perceived. Speaker like this get tiring over time, and when you get them home and live with them for a while ...very quickly... the thrill is gone.
Generally you do not design speaker to a room unless you know you are going to be in that room until you die. Room specific speaker work best in the room they are specific too.
However, if you want to anticipate trouble frequencies within a room, simply divide the room dimensions into the speed of sound. Using American units, let's say you have a room that is 18 feet long. The speed of sound in air is 1128 ft/s.
So -
F1 = S/y = 1128/18 = 62.7hz
This is the frequency that that dimension will resonate at.
Let's say the other dimension is 15 feet =
F2 = 1128/15 = 75.2 hz
And let's say you have 8 foot ceilings -
F3 = 1128/8 = 141 hz
Let's say you place you speaker 3 feet from the side wall, and 2 feet from the wall behind the speaker. We can find the frequencies associate with these distances.
F4 = 1128/3 = 376hz
F5 = 1128/2 = 564hz
So, we have these frequencies to consider.
As to mids and high, though it depends on the circumstance, generally, the more you amp up the bass, the muddier your midrange gets. For example, a speaker that sounds fine in the middle of the room, when pushed into the corner is likely to have great powerful bass, but the midrange is likely to be cloudy, muddled, and muddy.
So ...what to do...what to do?
Answer, design the speaker to a reasonable blend of your taste, a fair evaluation of your room acoustics, and to a fair standard of fidelity. Everything in life is a compromise. Just remember that life and speakers are like squeezing a balloon, you can get it down in one area, but it is going to blow up in another. Find the workable compromise.
Next, I'm not sure of the size of your room. You gave it in METERS, yet apologies for using inches. So, it that 20 to 30 Square Feet or 20 to 30 Square Meters?
25 Squares Meter would be 269 Square Feet, which would be 16.4 feet x 16.4 feet. That is quite a difference. Best to not give Square dimensions but give actual Length x Width x Height, then we have something we can work with.
Further the floor-plan matters. Is this a open floor-plan into another room; sort of a combined Kitchen/Living Room or perhaps a combined Living Room/Dining Room? And is that 16x16 both spaces or just one.
What does it have for window? Fireplace? Small closed doors, or large open doors?
These details carry greater weigh in deciding what kind of speaker a given room can accommodate. If this is a completely close 16x6 room (don't know, just using it as an example), then good quality bookshelf might be enough.
In my living room, which is about 16ft x17ft, I have TWO 12" 3-way PLUS TWO floorstanding with TWIN 8" bass drivers each. But, I have an open floor plan this room of 16ft x 17ft opens into a kitchen and entry way that is slightly larger than that. While my functional listening space is small, the available space that the speakers unload into is quite large. So you can see how the specifics of the circumstances can make a difference.
Given the speakers I've listed above, I would personally rather have large speakers played a bit quieter, than have small speaker played a bit louder. The amount of air that you move can have an impact on your perception of the weight of the music.
When designing speaker, if you are using software, the software might ask you to choose between THREE types of speakers.
1.) Most Bass
2.) Flattest Response
3.) Lowest Response
You only get one.
Most Bass will have a big bass peak. This is actually setting the "Q" factor. With a "Q" of 2, you get a really big bass bump. With a "Q" of 1 you get a more modest bass bump. With a "Q" of 0.7 you get the flattest response. With a "Q" of 0.5 the bass starts to roll off much earlier, but rolls off slowly and goes deeper.
So -
Q = 1.0 = Most Bass
Q = 0.7 = Flattest Response
Q = 0.5 = Lowest Response
Q=0.7 is considered ideal for faithful reproduction.
Q=1.0 is about as high as anyone would ever go. Above that, you get into excessive bass.
Q=0.5 is used less often but if you want to go as deep as possible, this is the way to do it, but it comes with some sacrifice. It is the balloon analogy, get it down in one place and it expand in another. Or gain in one place, lose in another.
None of these are wrong, if they give you what you want. Just make sure you REALLY want what you get.
Also, as I have mentioned, perception can be deceiving. You say to someone that my speakers go down to 25hz, and their response is, wow, that must be loud. NO. One has nothing to do with the other, That's like one person saying my banana is green and having the other person respond with "Ford". One has nothing to do with the other. Deep is Deep and Loud is Loud, one is not necessarily the other.
There are many absolutely stunning bookshelf speakers that play music so sweetly it would make you weep. But being small, they don't have great bass numbers. What they do have is crystal clarity and faithful reproduction. (B&W CM5, Dynaudio 160, Kef LS50, and many more).
Myself, I prefer floorstanding. I'm old school, to my ancient mind an 8" speaker is tiny. But then the speakers I grew up with don't exist any more. In today's world an 8" bass driver is consider big.
Ideally, at least in my mind, a good bookshelf speaker should have rated -6dB response BELOW 50hz, though below 40hz would be better.
A good floorstanding should have rated -6dB response BELOW 40hz. Ideally though, 30hz or a bit deeper.
But the key to that statement isn't 40hz or 50hz; it is GOOD speaker. I would rather have a truly stunning speaker with less bass, than have a truly bad speaker with over hyped bass.
As to -3dB response vs -6dB response. -3dB is virtually flat. -6dB is down slightly but still very usable; generally considered the low end of the truly usable range.
That's probably more than you wanted to know, and probably doesn't specifically address you real questions, but it should give you some framework.
Steve/bluwizard
That is precisely the range you spoke of. I had some very low cost speaker, Sony 5" bookshelf with rated bass at 80hz, but they still sounded like they had very good bass. But perception is not reality. The sounded like they had good bass, but they didn't.
Now, the same trick can be applied to cheaper floorstanding speakers too. The put a big bass bump in, young men are impressed. They buy the speakers.
But, in better floorstanding, and bookshelf too, you don't want to be fooled, quite the opposite, you want reproduction as close as possible to what is contained on the Medium (vinyl records, CDs, etc...). Therefore these better speakers don't have over-amp, hyper, droning, exaggerated bass. But they sound stunning. And I have hear very very expensive very clear speaker that initially didn't seem to have any bass until I realized I could feel it slamming into my body. It was rendered perfectly, or as perfectly as $4000/pr speaker can.
There are other tricks as well. If you want to give the illusion of great life and presence to speaker, you simply build in an upper midrange bump.
But to a finely tuned ear, all these 'Tricks' get tiring after a while.
So, don't confuse perception with reality. It is easy to create perception in speaker, with out actually delivering on the thing that is perceived. Speaker like this get tiring over time, and when you get them home and live with them for a while ...very quickly... the thrill is gone.
Generally you do not design speaker to a room unless you know you are going to be in that room until you die. Room specific speaker work best in the room they are specific too.
However, if you want to anticipate trouble frequencies within a room, simply divide the room dimensions into the speed of sound. Using American units, let's say you have a room that is 18 feet long. The speed of sound in air is 1128 ft/s.
So -
F1 = S/y = 1128/18 = 62.7hz
This is the frequency that that dimension will resonate at.
Let's say the other dimension is 15 feet =
F2 = 1128/15 = 75.2 hz
And let's say you have 8 foot ceilings -
F3 = 1128/8 = 141 hz
Let's say you place you speaker 3 feet from the side wall, and 2 feet from the wall behind the speaker. We can find the frequencies associate with these distances.
F4 = 1128/3 = 376hz
F5 = 1128/2 = 564hz
So, we have these frequencies to consider.
As to mids and high, though it depends on the circumstance, generally, the more you amp up the bass, the muddier your midrange gets. For example, a speaker that sounds fine in the middle of the room, when pushed into the corner is likely to have great powerful bass, but the midrange is likely to be cloudy, muddled, and muddy.
So ...what to do...what to do?
Answer, design the speaker to a reasonable blend of your taste, a fair evaluation of your room acoustics, and to a fair standard of fidelity. Everything in life is a compromise. Just remember that life and speakers are like squeezing a balloon, you can get it down in one area, but it is going to blow up in another. Find the workable compromise.
Next, I'm not sure of the size of your room. You gave it in METERS, yet apologies for using inches. So, it that 20 to 30 Square Feet or 20 to 30 Square Meters?
25 Squares Meter would be 269 Square Feet, which would be 16.4 feet x 16.4 feet. That is quite a difference. Best to not give Square dimensions but give actual Length x Width x Height, then we have something we can work with.
Further the floor-plan matters. Is this a open floor-plan into another room; sort of a combined Kitchen/Living Room or perhaps a combined Living Room/Dining Room? And is that 16x16 both spaces or just one.
What does it have for window? Fireplace? Small closed doors, or large open doors?
These details carry greater weigh in deciding what kind of speaker a given room can accommodate. If this is a completely close 16x6 room (don't know, just using it as an example), then good quality bookshelf might be enough.
In my living room, which is about 16ft x17ft, I have TWO 12" 3-way PLUS TWO floorstanding with TWIN 8" bass drivers each. But, I have an open floor plan this room of 16ft x 17ft opens into a kitchen and entry way that is slightly larger than that. While my functional listening space is small, the available space that the speakers unload into is quite large. So you can see how the specifics of the circumstances can make a difference.
Given the speakers I've listed above, I would personally rather have large speakers played a bit quieter, than have small speaker played a bit louder. The amount of air that you move can have an impact on your perception of the weight of the music.
When designing speaker, if you are using software, the software might ask you to choose between THREE types of speakers.
1.) Most Bass
2.) Flattest Response
3.) Lowest Response
You only get one.
Most Bass will have a big bass peak. This is actually setting the "Q" factor. With a "Q" of 2, you get a really big bass bump. With a "Q" of 1 you get a more modest bass bump. With a "Q" of 0.7 you get the flattest response. With a "Q" of 0.5 the bass starts to roll off much earlier, but rolls off slowly and goes deeper.
So -
Q = 1.0 = Most Bass
Q = 0.7 = Flattest Response
Q = 0.5 = Lowest Response
Q=0.7 is considered ideal for faithful reproduction.
Q=1.0 is about as high as anyone would ever go. Above that, you get into excessive bass.
Q=0.5 is used less often but if you want to go as deep as possible, this is the way to do it, but it comes with some sacrifice. It is the balloon analogy, get it down in one place and it expand in another. Or gain in one place, lose in another.
None of these are wrong, if they give you what you want. Just make sure you REALLY want what you get.
Also, as I have mentioned, perception can be deceiving. You say to someone that my speakers go down to 25hz, and their response is, wow, that must be loud. NO. One has nothing to do with the other, That's like one person saying my banana is green and having the other person respond with "Ford". One has nothing to do with the other. Deep is Deep and Loud is Loud, one is not necessarily the other.
There are many absolutely stunning bookshelf speakers that play music so sweetly it would make you weep. But being small, they don't have great bass numbers. What they do have is crystal clarity and faithful reproduction. (B&W CM5, Dynaudio 160, Kef LS50, and many more).
Myself, I prefer floorstanding. I'm old school, to my ancient mind an 8" speaker is tiny. But then the speakers I grew up with don't exist any more. In today's world an 8" bass driver is consider big.
Ideally, at least in my mind, a good bookshelf speaker should have rated -6dB response BELOW 50hz, though below 40hz would be better.
A good floorstanding should have rated -6dB response BELOW 40hz. Ideally though, 30hz or a bit deeper.
But the key to that statement isn't 40hz or 50hz; it is GOOD speaker. I would rather have a truly stunning speaker with less bass, than have a truly bad speaker with over hyped bass.
As to -3dB response vs -6dB response. -3dB is virtually flat. -6dB is down slightly but still very usable; generally considered the low end of the truly usable range.
That's probably more than you wanted to know, and probably doesn't specifically address you real questions, but it should give you some framework.
Steve/bluwizard
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Thank you for links and very informative explanations. I realise it's more complicated than my simple question...
I remenber Jean Hiraga who are found of Altec write somewhere he prefer the bass maid with large bass driver (15") than the same quantity or moving air maid by several littlier units !
I listen most of the time two floorstandings : Kef 104/2 (55 hz to 20k hz: +/- 2 DB) and Boston Acoustics Lynfield 400L (35 hz to 35 k hz : +/- 3 DB).
With your words : The Kef plays louder (very punchy, the bass impact are stunning but not very low). The Boston plays deeper, the impact of bass seems lower than the Kef : bass, drums, electric bass...I find the medium to have a good density but clear too (many details and accurate tones)
The Boston are very accurate, more than the Kef, but the Kef are more lively... the Kef is for me better and I can listen to it longer without fatigue (maybe too the Boston has a bump at something like 5 k Hz which I paddle for the moment with...toilett paper on the fabric grill).
The two speakers have a symetrical close load for the bass : two 8", both have a low pass filter before 150 hz.
Maybe the Q of the boston are lower than the Kef ? Maybe I speak about mid bass ??? I like the JBL sound for the bass for example ! Some people like Siegried Linkwitz believe only if I remember into 0,5 Q !
If I heard a Proac D15 : (8" vented box) : it's a two way, Proac set up to maje them loudness : bump in mid bass and bass and a bump in treble range : So the speakers goes deep, but the bass are thin...
Maybe I like mid bass ! Where is the impact of battery ? 60 hz, 80 hz ; I listen to all sort of musics but main Jazz and Rock, classical is 10% !
I remenber Jean Hiraga who are found of Altec write somewhere he prefer the bass maid with large bass driver (15") than the same quantity or moving air maid by several littlier units !
I listen most of the time two floorstandings : Kef 104/2 (55 hz to 20k hz: +/- 2 DB) and Boston Acoustics Lynfield 400L (35 hz to 35 k hz : +/- 3 DB).
With your words : The Kef plays louder (very punchy, the bass impact are stunning but not very low). The Boston plays deeper, the impact of bass seems lower than the Kef : bass, drums, electric bass...I find the medium to have a good density but clear too (many details and accurate tones)
The Boston are very accurate, more than the Kef, but the Kef are more lively... the Kef is for me better and I can listen to it longer without fatigue (maybe too the Boston has a bump at something like 5 k Hz which I paddle for the moment with...toilett paper on the fabric grill).
The two speakers have a symetrical close load for the bass : two 8", both have a low pass filter before 150 hz.
Maybe the Q of the boston are lower than the Kef ? Maybe I speak about mid bass ??? I like the JBL sound for the bass for example ! Some people like Siegried Linkwitz believe only if I remember into 0,5 Q !
If I heard a Proac D15 : (8" vented box) : it's a two way, Proac set up to maje them loudness : bump in mid bass and bass and a bump in treble range : So the speakers goes deep, but the bass are thin...
Maybe I like mid bass ! Where is the impact of battery ? 60 hz, 80 hz ; I listen to all sort of musics but main Jazz and Rock, classical is 10% !
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So for the bass , the Proac D15 is the worse even with their beautifull tones.
Are a U Frame or a W open box à la Linkwitz, good solutions to have lively and detailed bass with a driver with high Q ? Can the total Q easy to set up without linkwitz transform/ elctronic compensation ? Or do we go with box to have a slighty - 6 DB below 30 to 40 hz and set up the total Q with the Box and the driver together?
In my mind a good driver has a low FS and a QTS around 0,5 to 0,6 (so better closed box), but don't understand why some are more lively than over ? Can we have deep and loud with an electronic set up (miniDSP, Behringer) or do we have to go 4 way filter : 30 to 80 hz with 15" ; 80 to 150 with 10".
I plan to go with a no huge DIY ESL planar for mid/tweeter...but septical for the design of a bass & mid bass before 200 hz. Is electronic compensation not equall to distorsion (more movement of bass driver) ? I don't want to go with a bass line area for cost and WAF... push pull of 15" will be a maximum and Onken too big? OB or little closed with 10" or 8" ? Closed give detailled bass but has box sound so why go to planar with it ? But Open bass cabinet with low Q driver à la Linkwitz = electronic compensation??? Some says at the opposite that drivers with to high Q (>1) for bass give not good impact !
I forgett : my listening room are rectangular : 5 meters to 7 meters and 2,8 meters height
Are a U Frame or a W open box à la Linkwitz, good solutions to have lively and detailed bass with a driver with high Q ? Can the total Q easy to set up without linkwitz transform/ elctronic compensation ? Or do we go with box to have a slighty - 6 DB below 30 to 40 hz and set up the total Q with the Box and the driver together?
In my mind a good driver has a low FS and a QTS around 0,5 to 0,6 (so better closed box), but don't understand why some are more lively than over ? Can we have deep and loud with an electronic set up (miniDSP, Behringer) or do we have to go 4 way filter : 30 to 80 hz with 15" ; 80 to 150 with 10".
I plan to go with a no huge DIY ESL planar for mid/tweeter...but septical for the design of a bass & mid bass before 200 hz. Is electronic compensation not equall to distorsion (more movement of bass driver) ? I don't want to go with a bass line area for cost and WAF... push pull of 15" will be a maximum and Onken too big? OB or little closed with 10" or 8" ? Closed give detailled bass but has box sound so why go to planar with it ? But Open bass cabinet with low Q driver à la Linkwitz = electronic compensation??? Some says at the opposite that drivers with to high Q (>1) for bass give not good impact !
I forgett : my listening room are rectangular : 5 meters to 7 meters and 2,8 meters height
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Here is something that might be helpful.
It is the relative size of different bass drivers -
4.5" - 1
5.0" - 1.3
6.5" - 2.6
8.0" - 4.3
10" - 6.8
12" - 9.9
15" - 16.0
This was given to me by a member of the forums in response to an old post I made. I believe it is based on the Area of a Circle, and not on the actual surface area of specific speakers.
Here is how we use this information. How many 8" drivers does it take to equal a 12" bass driver or a 15" bass driver?
The 8" is 4.3
A 12" is 9.9
a 15" is 16
So, how many 8" to equal a 12" -
X = Twelve_inch/Eight_inch = 9.9/4.3 = 2.3
It take 2.3 EIGHT inch to equal one 12" bass driver.
How may 8" to equal one 15"
X = Fifteen_inch/Eight_inch = 16/4.3 = 3.73
It take 3.73 EIGHT inch drivers to equal one 15" driver.
It is not uncommon to see floorstanding speakers with 4 smaller bass drivers. They would move roughly the same air as a 15" bass driver.
However, 15" bass driver are heavy. They have a lot of mass to move, and a lot of inertia to over come, both standing inertia and moving inertia. It take a lot to get them moving and once moving, it takes a lot to get them to stop. However, large bass drives can have the capacity to go VERY DEEP and they move a lot of air.
Smaller bass driver obviously have less mass and therefore less inertia, but it is harder to get them down at or near 30hz.
Take a Subwoofer for example, always large bass drivers and some have the capability to be functional down to about 15hz. But, there is a trade off. It is the balloon analogy. When you make them go deeper, you lose on the top end. Most Subwoofer drivers are probably not really functional above 500hz, and in an application, they are not asked to go above 250hz.
Also, the Subwoofer has allowed Front Speakers to sacrifice a bit of bass on the belief the user will have a Subwoofer to cover the deepest of the deep. So, there is some logic to multi-driver modern designs. And modern "Tower" designs have been refined to a pretty high degree.
There is also the FACE, meaning the front of the cabinet. While I don't mind, most people today want their speakers to be as unobtrusive as possible. So, today we have tall narrow cabinets with smaller bass drivers. You can add enough small drivers to ...more or less... equal a big driver. But you are butting against the inherent limits of the smaller drivers and the required cabinet size.
Though, to be fair, you can get 6.5" and 8" bass drivers that go pretty deep.
Case in point, these are Dayton Classic 6.5" and 8" both rated at 30hz on the low end, and both with pretty reasonable cabinet requirements -
Dayton Audio DC160-8 6-1/2" Classic Woofer 295-305
Dayton Audio DC200-8 8" Classic Woofer 295-310
Personally, if I can get a final finished speaker that goes down very near 30hz I'm happy. Likely with boundary or room re-enforcement, a speaker rated at 30hz will give me a few more HZ on the bottom end. So that should take me down into the Mid to Upper 20's somewhere.
Personally, from test in my listening room, I don't recognize anything below about 28hz as a note or a tone. Yes, I can hear it, but it is just the Fuff-Fuff-Fuff flapping of the cone. The only advantage to Sub-30hz capability is for Shock Waves in movie sound tracks. That's not something you have to worry about for music.
My deepest speakers have 2x8" each in a 3.5-way configuration. These are rated down to 28hz at -6dB. That's pretty good for two 8" bass drivers. I also have a pair of DIY speakers with one 12" bass driver each, but these go down to about ~40hz on the low end, none the less they sound pretty good.
Last weekend, I could feel the entire room shake and rumble during the battle scene of Lord of the Rings - 3. Given that, I'm perfectly content to concentrate my very lean budget on Stereo equipment rather than a AV setup.
If you'll pardon a very old and feeble mind -
5 meters = 16.4 feet
7 meters = 23 feet
2.8 meters = 9.2 feet
How and where is the system placed in that room?
Does the amp and speaker sit along the Long Wall or the Short Wall?
If on the short wall, then it should play very well into the 23 foot (7 meter) length. If on the broad wall playing into the shorter 16.4 foot (5 meter) dimension, it could still be reasonably good depending on the room acoustics and where along the wall the speakers are placed.
When considering what type of speaker to design and what characteristics to design into the speakers, you do need to consider the room and how much space you will have available for the speakers.
Let me illustrate from my own experience. I had some JBL Stadium Venue speakers, that were very much like the speaker I have now. They had 2x8" bass drivers each in a 3.5-way configuration, but they had substantially more bass than my current speakers. As a result, they really did not like to be close to the walls. When placed 12" from the wall behind the speaker, the bass was great, but the midrange was terrible - muddy and cloudy. To really functionally use these speaker, they would need at bare minimum 18 inches behind them and 24 inches or more would have been better.
However, I replaced those speakers with 2x8" in a 3.5-way configuration (Wharfedale) that had more manageable bass. They are perfectly content to be placed 12" from the wall behind. And the Wharfedale as indicated above have a rated response of 28hz at -6dB. I'm not complaining.
So, if you are planning to build a big bass bump into your speakers, then also plan on giving them a lot of room. Then weigh how functional that demand is for space in you room with your limits for speaker placement.
There isn't a table of ratios of amount of bass to room size, because there are too many other factors to consider - placement, how bass heavy the speaker is, room acoustics, and other factors. It is more a common sense approach.
You can make any choice you want, as long as you are willing to take the Minuses that come with any Plus that you build into the speaker. Again as an example, if you build in excessive bass, then count on large spacing requirements when you place the speaker in the room, and count on the Midrange being slightly muddy.
I think most would say build your speaker for the flattest response, then when in the room, if you need more bass either turn up the bass control or add a subwoofer.
Hopefully that gives you some perspective.
Steve/bluewizard
It is the relative size of different bass drivers -
4.5" - 1
5.0" - 1.3
6.5" - 2.6
8.0" - 4.3
10" - 6.8
12" - 9.9
15" - 16.0
This was given to me by a member of the forums in response to an old post I made. I believe it is based on the Area of a Circle, and not on the actual surface area of specific speakers.
Here is how we use this information. How many 8" drivers does it take to equal a 12" bass driver or a 15" bass driver?
The 8" is 4.3
A 12" is 9.9
a 15" is 16
So, how many 8" to equal a 12" -
X = Twelve_inch/Eight_inch = 9.9/4.3 = 2.3
It take 2.3 EIGHT inch to equal one 12" bass driver.
How may 8" to equal one 15"
X = Fifteen_inch/Eight_inch = 16/4.3 = 3.73
It take 3.73 EIGHT inch drivers to equal one 15" driver.
It is not uncommon to see floorstanding speakers with 4 smaller bass drivers. They would move roughly the same air as a 15" bass driver.
However, 15" bass driver are heavy. They have a lot of mass to move, and a lot of inertia to over come, both standing inertia and moving inertia. It take a lot to get them moving and once moving, it takes a lot to get them to stop. However, large bass drives can have the capacity to go VERY DEEP and they move a lot of air.
Smaller bass driver obviously have less mass and therefore less inertia, but it is harder to get them down at or near 30hz.
Take a Subwoofer for example, always large bass drivers and some have the capability to be functional down to about 15hz. But, there is a trade off. It is the balloon analogy. When you make them go deeper, you lose on the top end. Most Subwoofer drivers are probably not really functional above 500hz, and in an application, they are not asked to go above 250hz.
Also, the Subwoofer has allowed Front Speakers to sacrifice a bit of bass on the belief the user will have a Subwoofer to cover the deepest of the deep. So, there is some logic to multi-driver modern designs. And modern "Tower" designs have been refined to a pretty high degree.
There is also the FACE, meaning the front of the cabinet. While I don't mind, most people today want their speakers to be as unobtrusive as possible. So, today we have tall narrow cabinets with smaller bass drivers. You can add enough small drivers to ...more or less... equal a big driver. But you are butting against the inherent limits of the smaller drivers and the required cabinet size.
Though, to be fair, you can get 6.5" and 8" bass drivers that go pretty deep.
Case in point, these are Dayton Classic 6.5" and 8" both rated at 30hz on the low end, and both with pretty reasonable cabinet requirements -
Dayton Audio DC160-8 6-1/2" Classic Woofer 295-305
Dayton Audio DC200-8 8" Classic Woofer 295-310
Personally, if I can get a final finished speaker that goes down very near 30hz I'm happy. Likely with boundary or room re-enforcement, a speaker rated at 30hz will give me a few more HZ on the bottom end. So that should take me down into the Mid to Upper 20's somewhere.
Personally, from test in my listening room, I don't recognize anything below about 28hz as a note or a tone. Yes, I can hear it, but it is just the Fuff-Fuff-Fuff flapping of the cone. The only advantage to Sub-30hz capability is for Shock Waves in movie sound tracks. That's not something you have to worry about for music.
My deepest speakers have 2x8" each in a 3.5-way configuration. These are rated down to 28hz at -6dB. That's pretty good for two 8" bass drivers. I also have a pair of DIY speakers with one 12" bass driver each, but these go down to about ~40hz on the low end, none the less they sound pretty good.
Last weekend, I could feel the entire room shake and rumble during the battle scene of Lord of the Rings - 3. Given that, I'm perfectly content to concentrate my very lean budget on Stereo equipment rather than a AV setup.
If you'll pardon a very old and feeble mind -
5 meters = 16.4 feet
7 meters = 23 feet
2.8 meters = 9.2 feet
How and where is the system placed in that room?
Does the amp and speaker sit along the Long Wall or the Short Wall?
If on the short wall, then it should play very well into the 23 foot (7 meter) length. If on the broad wall playing into the shorter 16.4 foot (5 meter) dimension, it could still be reasonably good depending on the room acoustics and where along the wall the speakers are placed.
When considering what type of speaker to design and what characteristics to design into the speakers, you do need to consider the room and how much space you will have available for the speakers.
Let me illustrate from my own experience. I had some JBL Stadium Venue speakers, that were very much like the speaker I have now. They had 2x8" bass drivers each in a 3.5-way configuration, but they had substantially more bass than my current speakers. As a result, they really did not like to be close to the walls. When placed 12" from the wall behind the speaker, the bass was great, but the midrange was terrible - muddy and cloudy. To really functionally use these speaker, they would need at bare minimum 18 inches behind them and 24 inches or more would have been better.
However, I replaced those speakers with 2x8" in a 3.5-way configuration (Wharfedale) that had more manageable bass. They are perfectly content to be placed 12" from the wall behind. And the Wharfedale as indicated above have a rated response of 28hz at -6dB. I'm not complaining.
So, if you are planning to build a big bass bump into your speakers, then also plan on giving them a lot of room. Then weigh how functional that demand is for space in you room with your limits for speaker placement.
There isn't a table of ratios of amount of bass to room size, because there are too many other factors to consider - placement, how bass heavy the speaker is, room acoustics, and other factors. It is more a common sense approach.
You can make any choice you want, as long as you are willing to take the Minuses that come with any Plus that you build into the speaker. Again as an example, if you build in excessive bass, then count on large spacing requirements when you place the speaker in the room, and count on the Midrange being slightly muddy.
I think most would say build your speaker for the flattest response, then when in the room, if you need more bass either turn up the bass control or add a subwoofer.
Hopefully that gives you some perspective.
Steve/bluewizard
Thank you, the values and links are very usefull. It helps.
The speakers sit on the shorter wall at 32 inches fron the wall behind and 40 inches from the side walls. Sofa is 140 inches from the front of the speakers.
In my mind, 50 inches width for a cabinet is not a no go... but if the cabinet triple its height size (line aray).
My hope is not to have plenty of bass (louder) but find something lively like my Kef 104/2 ref... impact but not grand orgue... I believe I can live with weak two first octaves...but not above. In the kef 104/2 each 8" has just a little closed box for load, but are push-pull with a larger common load who beam through a big hole in the front of the cabinet (just under the MTM)...these 8" kef unit have not a special big Q (<0,4 to 0,5)... maybe they goes - 6 DB under 55 hz !
The speakers sit on the shorter wall at 32 inches fron the wall behind and 40 inches from the side walls. Sofa is 140 inches from the front of the speakers.
In my mind, 50 inches width for a cabinet is not a no go... but if the cabinet triple its height size (line aray).
My hope is not to have plenty of bass (louder) but find something lively like my Kef 104/2 ref... impact but not grand orgue... I believe I can live with weak two first octaves...but not above. In the kef 104/2 each 8" has just a little closed box for load, but are push-pull with a larger common load who beam through a big hole in the front of the cabinet (just under the MTM)...these 8" kef unit have not a special big Q (<0,4 to 0,5)... maybe they goes - 6 DB under 55 hz !
Search Bass Presence Range, that should give you some idea of the range we are talking about.
If you build your speaker with a "Q" of 1, they will have a natural boost in the bass region.
Here is a link to a webpage that has the graph of the various "Q" Values -
Speaker Box Enclosure Designer / Calculator Help
Notice Q=0.707 is shown in Red.
Q of 0.5 are you can see, start to roll-off sooner, but ultimately goes much deeper.
Anything over a Q of 1 and yes, you get a great bass bump, but the roll-off is very steep and simply does not go as low
As I said, you don't get something for nothing. If you want that big bass bump, then accept that the speaker are not going to go as low.
With the exception of Subwoofers, I suspect most speaker are 0.707 which most consider ideal. For Bass Heads, they might use a Q of 1. In a Subwoofer, where depth is more important than quantity, they might use a Q of 0.5.
Hope that helps.
Steve/bluewizard
If you build your speaker with a "Q" of 1, they will have a natural boost in the bass region.
Here is a link to a webpage that has the graph of the various "Q" Values -
Speaker Box Enclosure Designer / Calculator Help
Notice Q=0.707 is shown in Red.
Q of 0.5 are you can see, start to roll-off sooner, but ultimately goes much deeper.
Anything over a Q of 1 and yes, you get a great bass bump, but the roll-off is very steep and simply does not go as low
As I said, you don't get something for nothing. If you want that big bass bump, then accept that the speaker are not going to go as low.
With the exception of Subwoofers, I suspect most speaker are 0.707 which most consider ideal. For Bass Heads, they might use a Q of 1. In a Subwoofer, where depth is more important than quantity, they might use a Q of 0.5.
Hope that helps.
Steve/bluewizard
but what is "a good bass"?
isn't a good bass a bass that sounds good?
what counts, at the end of the day, is how it sounds, doesn't it?
but HiFi is about audible illusions - in this domain perception IS reality
measurements doesn't sound
there is no such alternative - what about a truly good speaker with somewhat hyped bass?
a quick search and here is what can be found ia.: EQ BY THE OCTAVE:
Hi Steve. I use 15" woofers. Their cones (Mms) are, when area is taken into account lighter than either of the drivers you posted. Their fs is higher than either at 39Hz. I don't expect much from them below 60Hz but I EQ them and they respond
Where I gain with them is efficiency. I have used these crossed as high as 1.2kHz and they performed well...not the best I've heard but fairly hi-fi all the same.
I also used these 15" drivers in an H frame once. I used EQ to get flat to below 40Hz. I could get good levels out of them but I wouldn't use any less cone area than this.
I don't quite know how to describe them, but they sounded fairly clean but involved the room considerably. I don't say this because that is necessarily a bad thing...they give this spacious feeling and it is quite obvious. It just doesn't happen to be what I like.
AllenB,
From what I understand, you are saying the mass or weight of your speakers per square inch is less than the speaker I linked to.
However, you have many more square inches. We are not moving bass drivers by the square inch, we are moving entire drivers, and if the entire mass or weight is high, then they have significant inertia.
I use 12" 3-way speakers, they go down to a good working 40hz, and they sound great. I've been listening to them all day today. I forgot how good they sound. Or I should say, they sound great for what they cost. Considering I've rebuilt them twice, the cabinets are now worth about three times what the drivers and crossover cost. I think the last rebuilt cost me over $200 and a aching back for two weeks. The speakers weight 50 pounds each.
I'm all for big bass drivers, but on the commercial front, those days are gone. Today, you would have a hard time selling a 12" full range speaker no matter how good it sounded. It is even worse for me, given that I live out in the middle of the frozen tundra of the upper midwest. That's one thing that stops me from upgrading my equipment, around here it is virtually impossible to sell audio equipment. I've got a working stereo that I can't give away.
But I also have speaker that have 2x 8"drivers each in a 3.5-way configuration. That is pretty close to a 12" bass driver.
As to the Original Poster, in the sense we have explained, you design the speaker to the room, but only in the most minor way. It is more personal preference, than specifically designing to the room.
And I think personal preference will guide your design more than the room. The room is primarily placement and acoustical considerations.
Steve/bluewizard
From what I understand, you are saying the mass or weight of your speakers per square inch is less than the speaker I linked to.
However, you have many more square inches. We are not moving bass drivers by the square inch, we are moving entire drivers, and if the entire mass or weight is high, then they have significant inertia.
I use 12" 3-way speakers, they go down to a good working 40hz, and they sound great. I've been listening to them all day today. I forgot how good they sound. Or I should say, they sound great for what they cost. Considering I've rebuilt them twice, the cabinets are now worth about three times what the drivers and crossover cost. I think the last rebuilt cost me over $200 and a aching back for two weeks. The speakers weight 50 pounds each.
I'm all for big bass drivers, but on the commercial front, those days are gone. Today, you would have a hard time selling a 12" full range speaker no matter how good it sounded. It is even worse for me, given that I live out in the middle of the frozen tundra of the upper midwest. That's one thing that stops me from upgrading my equipment, around here it is virtually impossible to sell audio equipment. I've got a working stereo that I can't give away.
But I also have speaker that have 2x 8"drivers each in a 3.5-way configuration. That is pretty close to a 12" bass driver.
As to the Original Poster, in the sense we have explained, you design the speaker to the room, but only in the most minor way. It is more personal preference, than specifically designing to the room.
And I think personal preference will guide your design more than the room. The room is primarily placement and acoustical considerations.
Steve/bluewizard
This is correct, yet we haven't discussed the motor system.
I tend to be wary of 15" drivers in general and there seem to be plenty of examples of bad ones out there. I use pro drivers and the crossover anecdote was implying that I'm not having transient response issues.
The OP is quite correct that bass perception varies greatly from setup to setup and does not seem to correlate with the actual speakers being used. This is simply because the room dominates the problem and the actual speakers are not very important.
But every room is different so what to do?
The solution is to use multiple subs spread around the room and EQ'd in situ. This is the only way that I have found to get great bass in an arbitrary room. Some years ago EQ may have been a problem, but these days with free PC software to do the measurements and EQ readily available through DSP there is simply no reason not to do things this way.
This technique makes the speaker type (ported, closed box, dipole, cardioid), Q, resonance, etc. completely irrelevant because you just EQ everything to what is needed in the specific room. The speakers size and power handling are relevant to the extent that they determine how loud (SPL) the system can go. Smaller speakers will only go to say 80 dB, larger ones 100 dB and many 15"s will go to 120 dB. It all depends on what you are looking to achieve.
But every room is different so what to do?
The solution is to use multiple subs spread around the room and EQ'd in situ. This is the only way that I have found to get great bass in an arbitrary room. Some years ago EQ may have been a problem, but these days with free PC software to do the measurements and EQ readily available through DSP there is simply no reason not to do things this way.
This technique makes the speaker type (ported, closed box, dipole, cardioid), Q, resonance, etc. completely irrelevant because you just EQ everything to what is needed in the specific room. The speakers size and power handling are relevant to the extent that they determine how loud (SPL) the system can go. Smaller speakers will only go to say 80 dB, larger ones 100 dB and many 15"s will go to 120 dB. It all depends on what you are looking to achieve.
Hi Earl,
What is the Hz range of the subs you talk about ? For me there are two types of sub : one is for the two first octaves and the second try to solve everything (with difficulty) to 80 hz !
I'm pretty sure that the design between 60 to 100-150 hz is an important factor of a good speaker. But well no good bass without good midrange and treble (Iso curve : roll off after 2 k hz). Is it because mainly of the room or the Fletcher measures or something else... I surmise that it is true that the roll off of the low end is important to not mask the medium range; many talks of good Onken with a - 6 db or a - 12 db. It is very hard with Onken because vented box (more > 12/18db)and here these roll off are more like closed box (that i prefer IMHO)... Don't remenber the roll off of OB bass like S. Linkwitz !
Do you consider the +6 db renforcment by placing them nears the walls ? Because you maybe put many subs around the room, are they littlier than conventional subs ?
At the low end where is the roll off beginning ? 40 hz ? - 6 db ore more (vented box ?) you use in your set up?
I think maybe of planar ESL satelites for the main 200 hz to 20K hz (well maybe more 15 k at my 44 !) at 1 meter to the listener and mid-bass - bass box in a more classical position... but he delay between the two ?? electronic delay can solve that ?
@ AllenB,
Hi,
For the 15" I'm surprise it can be used above 400 hz for directivity and good sound stage...and the range above 200 give often a not coherent sound for male singers...most of the time. And what about distorsion and subharmonics above 100 hz to 1200 hz when big movement of the cone of a 15" bass driver ? septical here !
If I make an analogy, maybe I like the mid bass region the Quarter wave box do (but the load is too long for good reactivity no ?)
What is the Hz range of the subs you talk about ? For me there are two types of sub : one is for the two first octaves and the second try to solve everything (with difficulty) to 80 hz !
I'm pretty sure that the design between 60 to 100-150 hz is an important factor of a good speaker. But well no good bass without good midrange and treble (Iso curve : roll off after 2 k hz). Is it because mainly of the room or the Fletcher measures or something else... I surmise that it is true that the roll off of the low end is important to not mask the medium range; many talks of good Onken with a - 6 db or a - 12 db. It is very hard with Onken because vented box (more > 12/18db)and here these roll off are more like closed box (that i prefer IMHO)... Don't remenber the roll off of OB bass like S. Linkwitz !
Do you consider the +6 db renforcment by placing them nears the walls ? Because you maybe put many subs around the room, are they littlier than conventional subs ?
At the low end where is the roll off beginning ? 40 hz ? - 6 db ore more (vented box ?) you use in your set up?
I think maybe of planar ESL satelites for the main 200 hz to 20K hz (well maybe more 15 k at my 44 !) at 1 meter to the listener and mid-bass - bass box in a more classical position... but he delay between the two ?? electronic delay can solve that ?
@ AllenB,
Hi,
For the 15" I'm surprise it can be used above 400 hz for directivity and good sound stage...and the range above 200 give often a not coherent sound for male singers...most of the time. And what about distorsion and subharmonics above 100 hz to 1200 hz when big movement of the cone of a 15" bass driver ? septical here !
If I make an analogy, maybe I like the mid bass region the Quarter wave box do (but the load is too long for good reactivity no ?)
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I like the analogy beween the two words : louder and deeper, i suspect the kef 104/2 ref are louder at 55 hz beginning roll off than the deeper Boston acoustics Lynfield with their two 6,5 " bass per Box with their 35 hz (-3 db)... maybe the perception of impacts (drums, battery, bass guitar...) are higher with the kef and give virtually more life ! Maybe the lake of bass with the kefs highlight the mid bass ?
I would like to have a measurement of the kefs but I haven't...And listen the Kef 107 to understand how it sound with more bass (same construction technics)
I would like to have a measurement of the kefs but I haven't...And listen the Kef 107 to understand how it sound with more bass (same construction technics)
I consider only two regions in a room that are treated differently - the modal range and the statistical range. These two are separated at the Schoeder Frequency which varies with the room and the absorption. It is typically about 150-200 Hz in a home listening room. In the modal range all source contribute to the net sound field. If one actually measures that field the whether or not there is a 6 dB gain from the room or corners or whatever is not relevant. It is what is measured. It is simply not possible to do good low frequency sound without measurements because there is just too much complexity with room coupling to predict the end result.
In my room I have one 15" sub, two 12" subs, and the mains have 15" woofers. I don't pay much attention to what any of these sources do in a free field. Its what they do in the actual room at the actual locations that matters and that's all. All sources can and do (to some extent) play in the modal region. Each sub is independently controlled based on measurements. The end result goes down to about 20 Hz. No sub actually goes that low, of course, but the room aids at these very low frequencies. As I said the room dictates the LF situation. All of my subs are monopoles.
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