Bit of an odd question since I'm not looking at comparing numbers and specs rather just over all speaker feel/sound. I realize this is comparing apples to oranges. Currently own a set of old technic Sb-a33. Mutlti way speakers. That uses. Two 10" Woofers one 5" mid base and a 2" dome tweeter. I'm wondering if I will get the same feel for bass from the from cerwin vega xls which has one 12" one 6.5" woofer and 1 tweeter as I would the technical. Looking fora bit of a Barney style answer
When you compare SpeakerA to SpeakerB you must have all the details on T/S parameters, SPL response, box tuning, box construction, crossover, etc....
One good 12" can produce more coherent bass than two good 10" speakers.
B&W White Paper on Bass
"Advantages of Producing a Coherent Wavefront:
One remarkable fact was consistently noticed during the development of the new 380mm bass unit for the Nautilus™801, and that was that a single large and stiff bass cone always sounded better than a number of smaller cones, even though they may well have had the same aggregated properties. One possible explanation for this is the concept of the production of a “coherent wave front”. This will be produced by a single large very stiff cone, which can couple with the air in a uniform manner over the whole of its surface area unaffected by differences in loading over that area. This behavior is to be compared with that of several cones which, even though they may be closely spaced, will still leave gaps of “uncoupled air” between them. The very stiff cone material of the large single driver, which is a thick sandwich of Kevlar® reinforced paper fibers with a very stiff skin, makes it less responsive to local changes of acoustic impedance or unbalanced modal pressures either behind or in front of the cone.
A “coherent wavefront” simply means there is either a constant or a smoothly changing phase relationship between neighbouring parts of the wavefront. So even if two drivers are relatively close together compared to a wavelength. Also, even if their contributions are equivalent to a single large driver, their different acoustic environments will mean that their outputs are slightly different, in terms of both amplitude and phase. Furthermore, the air between the drive units is not being driven at all and this will translate into a change in phase across the resulting wavefront as the air tries to “fill in” the lost contribution. One can postulate that, at low frequencies, air can “spill off the edges” of the individual cones more easily in an array of small cones, which obviously have more edges for it to spill off, than from a single large one. For instance, two 12 inch drivers have a combined circumference of 1630mm whereas one 15 inch cone has a circumference of only 1037 mm. It is also interesting to note in this context that the radiation resistance and reactance at low frequencies of one 15 inch cone, is actually larger than that of two 12 inch cones, even though the area of the 15 inch cone is 0.02m2 smaller than two 12 inch cones. This is because the change from a steadily rising radiation resistance characteristic at low frequencies, to a horizontal one at high frequencies, occurs at a lower frequency with one large driver than with two smaller. Mutual radiation impedance effects will redress this imbalance to some extent, provided that the two individual drivers are close enough together for one driver to acoustically load the other, though it will only be totally redressed if the array of small drivers produces a totally contiguous surface in all directions. With a less stiff cone, localized changes in rear (or front) pressure due to modes, or the presence of obstructions which prevent the free flow of air, will mean that the cone will flex in response to this differential loading during each vibration cycle. This flexure, quite apart from upsetting the resulting wavefront, may well ultimately cause the demise of the drive unit itself which may eventually even fall apart due to the repeated stresses. This is especially true of light cones trying to compress the air in very small boxes, but the principle can obviously be extended to large boxes having rear obstructions – such as a Matrix™ indeed – which inevitably impede the free flow of large volumes of air which occur at low frequencies.
All these effects are, of course, highly audible and conspire to remove the “punch” or timing effects which are often used to describe “fast” bass."
One good 12" can produce more coherent bass than two good 10" speakers.
B&W White Paper on Bass
"Advantages of Producing a Coherent Wavefront:
One remarkable fact was consistently noticed during the development of the new 380mm bass unit for the Nautilus™801, and that was that a single large and stiff bass cone always sounded better than a number of smaller cones, even though they may well have had the same aggregated properties. One possible explanation for this is the concept of the production of a “coherent wave front”. This will be produced by a single large very stiff cone, which can couple with the air in a uniform manner over the whole of its surface area unaffected by differences in loading over that area. This behavior is to be compared with that of several cones which, even though they may be closely spaced, will still leave gaps of “uncoupled air” between them. The very stiff cone material of the large single driver, which is a thick sandwich of Kevlar® reinforced paper fibers with a very stiff skin, makes it less responsive to local changes of acoustic impedance or unbalanced modal pressures either behind or in front of the cone.
A “coherent wavefront” simply means there is either a constant or a smoothly changing phase relationship between neighbouring parts of the wavefront. So even if two drivers are relatively close together compared to a wavelength. Also, even if their contributions are equivalent to a single large driver, their different acoustic environments will mean that their outputs are slightly different, in terms of both amplitude and phase. Furthermore, the air between the drive units is not being driven at all and this will translate into a change in phase across the resulting wavefront as the air tries to “fill in” the lost contribution. One can postulate that, at low frequencies, air can “spill off the edges” of the individual cones more easily in an array of small cones, which obviously have more edges for it to spill off, than from a single large one. For instance, two 12 inch drivers have a combined circumference of 1630mm whereas one 15 inch cone has a circumference of only 1037 mm. It is also interesting to note in this context that the radiation resistance and reactance at low frequencies of one 15 inch cone, is actually larger than that of two 12 inch cones, even though the area of the 15 inch cone is 0.02m2 smaller than two 12 inch cones. This is because the change from a steadily rising radiation resistance characteristic at low frequencies, to a horizontal one at high frequencies, occurs at a lower frequency with one large driver than with two smaller. Mutual radiation impedance effects will redress this imbalance to some extent, provided that the two individual drivers are close enough together for one driver to acoustically load the other, though it will only be totally redressed if the array of small drivers produces a totally contiguous surface in all directions. With a less stiff cone, localized changes in rear (or front) pressure due to modes, or the presence of obstructions which prevent the free flow of air, will mean that the cone will flex in response to this differential loading during each vibration cycle. This flexure, quite apart from upsetting the resulting wavefront, may well ultimately cause the demise of the drive unit itself which may eventually even fall apart due to the repeated stresses. This is especially true of light cones trying to compress the air in very small boxes, but the principle can obviously be extended to large boxes having rear obstructions – such as a Matrix™ indeed – which inevitably impede the free flow of large volumes of air which occur at low frequencies.
All these effects are, of course, highly audible and conspire to remove the “punch” or timing effects which are often used to describe “fast” bass."
That's surely the reason why they are now using two 10" woofers...
Do you have a link to that paper? I can't find it.
Do you have a link to that paper? I can't find it.
I guess manufacturers use whatever makes sales go up.
If buyers think more is better and looks appealing too,
that's what they are going to produce.
I would certainly DIY for myself rather one bigger bass
unit speaker and be done with it, than buy 2 parts which cost
more, present a heavier load and probably increase significantly
the box volume.
If buyers think more is better and looks appealing too,
that's what they are going to produce.
I would certainly DIY for myself rather one bigger bass
unit speaker and be done with it, than buy 2 parts which cost
more, present a heavier load and probably increase significantly
the box volume.
So to Sum it up the two 10 Woofers are really more show than go?
How difficult do you think it would be to find replacements for the mid base and replace the done tweeter with a horn?
How difficult do you think it would be to find replacements for the mid base and replace the done tweeter with a horn?
For an accurate answer to your question, one would have
to do a serious simulation and define every detail regarding
performance in mind.
I am not so certain I get what you are asking. You have a specific
speaker and you want to modify it?
to do a serious simulation and define every detail regarding
performance in mind.
I am not so certain I get what you are asking. You have a specific
speaker and you want to modify it?
The off axis response must be taken into account to.
I don't know if this favours 2x10" or 1x12", it depends on crossover steepness/frequency and the mid and high frequency drivers.
The "white paper" on coherent wave fronts seems like a sales pitch. White papers are always just white papers, probably rejected for peer reviewed publication. Iow: Don't trust them!
I don't know if this favours 2x10" or 1x12", it depends on crossover steepness/frequency and the mid and high frequency drivers.
The "white paper" on coherent wave fronts seems like a sales pitch. White papers are always just white papers, probably rejected for peer reviewed publication. Iow: Don't trust them!
"Tastes Great" ... "Less Filling"
Selecting a speaker is just like selecting a beer!
"Sounds Great" ... "Less Room Filling"
"Orgasmic Sound in a Sexy Package" = BIG SUCCESS!
The first B&W Nautilus 801 speaker used a single 15" woofer because the company engineers found that a single large woofer sounds better than a couple of small woofers.(below). The best selling and most advertised B&W Nautilus uses two 10" woofers because the design performs well and looks sexy. The TM-WW topology both looks good and perform well because it puts large woofer area into a narrow box, with the tweeter up at ear level.
WE ALREADY KNOW THAT:
---A single 15" woofer in a sealed cabinet with electronic Xover and room equalization will sound best.
---A sexy package would use two 10" woofers in a sealed cabinet with electronic Xover and room equalization.
---A sexy generic single-amp speaker would use two 10" woofers in a ported cabinet with passive Xover, plus a couple attenuation twist knobs.
---A three way speaker is required to approach 20-20Khz orgasmic sound.
Selecting a speaker is just like selecting a beer!
"Sounds Great" ... "Less Room Filling"
"Orgasmic Sound in a Sexy Package" = BIG SUCCESS!
The first B&W Nautilus 801 speaker used a single 15" woofer because the company engineers found that a single large woofer sounds better than a couple of small woofers.(below). The best selling and most advertised B&W Nautilus uses two 10" woofers because the design performs well and looks sexy. The TM-WW topology both looks good and perform well because it puts large woofer area into a narrow box, with the tweeter up at ear level.
WE ALREADY KNOW THAT:
---A single 15" woofer in a sealed cabinet with electronic Xover and room equalization will sound best.
---A sexy package would use two 10" woofers in a sealed cabinet with electronic Xover and room equalization.
---A sexy generic single-amp speaker would use two 10" woofers in a ported cabinet with passive Xover, plus a couple attenuation twist knobs.
---A three way speaker is required to approach 20-20Khz orgasmic sound.
Attachments
Hi,
One good 12" will crush 2 average 10" drivers but two good 10"
drivers wil pulverise one average 12" driver, so who knows ?
A better way of looking at it is two 8" are a bit less than a 12",
and two 10" are a bit less than a 15" in cone area. However
if you assume the bigger drivers also have more excursion
then 2x10 maps to 1x15, and 2x8 maps to 1x12.
Basically you can't generalise based on cone size / area.
THe B&W claims are highly contentious and suit them
down to the ground, certainly one crap woofer sounds
nowhere near as good as two good woofers ever.
According to their argument a 1x10 version of the
2x10 would sound better, or a 1x12, propaganda.
rgds, sreten.
One good 12" will crush 2 average 10" drivers but two good 10"
drivers wil pulverise one average 12" driver, so who knows ?
A better way of looking at it is two 8" are a bit less than a 12",
and two 10" are a bit less than a 15" in cone area. However
if you assume the bigger drivers also have more excursion
then 2x10 maps to 1x15, and 2x8 maps to 1x12.
Basically you can't generalise based on cone size / area.
THe B&W claims are highly contentious and suit them
down to the ground, certainly one crap woofer sounds
nowhere near as good as two good woofers ever.
According to their argument a 1x10 version of the
2x10 would sound better, or a 1x12, propaganda.
rgds, sreten.
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With more woofers you can have some slight pattern control. Spread those woofer over a wide area and you will have directivity in the bass.
"directivity in bass" is a myth! Just try with Edge! With 60cm (2') separation we get directivity only above 300Hz in the line of drivers. 90¤ to that (usually horizontally)directivity is the same for 1-2-3-4-5- etc. drivers.
Single big vs double small bass drivers comes from compromises between box width, volume and bass rolloff/tuning based on Qts. Two drivers can be placed on opposite sides of the box too, if we cross at say 300Hz. Then we also get force cancellation and a very narrow box (eg. Vivid Audio Giya G1 and many others)
Single big vs double small bass drivers comes from compromises between box width, volume and bass rolloff/tuning based on Qts. Two drivers can be placed on opposite sides of the box too, if we cross at say 300Hz. Then we also get force cancellation and a very narrow box (eg. Vivid Audio Giya G1 and many others)
A big bonus for 2 10" is that you can invert one and get massive distortion reductions. You can also mount them in a force cancelling setup to cancel vibration.
If you don't do that then I'd get the 12" due to simplicity. The distortion reduction and force cancellation is worth it though so I'd get the 2 10" 🙂
If you don't do that then I'd get the 12" due to simplicity. The distortion reduction and force cancellation is worth it though so I'd get the 2 10" 🙂
What is the deal with (you) people posting using adjectives like "massive" (above post) or "crush" and "pulverize" by Sreten in post #10. Give me a break... its difficult to make much of a claim about anything unless you know exactly the two drivers (10" and 12" for example) that you are talking about. I think this was Sreten's point, too. Unless you make clear what it is you are comparing any statement is just a generalization based on the author's preconceptions and biases, and this is just as much true for posts on this forum as it is for a "white paper" put out by a manufacturer who is interested in the business of selling product.
About the only thing I would have to concur with is the possibility for force cancellation by two drivers on opposing sides of an enclosure. Also, note that B&W DOES NOT use this arrangement of drivers!
Regarding "massive distortion reductions", ah... no. Maybe some even order cancellation if you are lucky.
There is a lot of even order distortion in the sub bass though. Factor in the equal loudness curve and the sub will be a lot more clean sounding than without the reduction, at least that is what I found when I listened =) Assuming of course that the drivers are of average design and don't have a fancy JBL differential drive motor or something similar.
If done properly only 2nd order would be reduced. Force cancellation to me is a must, regardless of driver quality. Gotta love opposed engines for the same reason. 🙂
For side mounted counter-force woofers I would want the center-to-center distance to the midrange to be a good margin less than a quarter wavelength.
For 200Hz crossover, C-to-C < 17"
Putting a pair of counter-force 18" woofers with an 80Hz-100Hz crossover frequency under a high efficiency speaker like Geddes new Summa15 would be a good design idea to me.
For 200Hz crossover, C-to-C < 17"
Putting a pair of counter-force 18" woofers with an 80Hz-100Hz crossover frequency under a high efficiency speaker like Geddes new Summa15 would be a good design idea to me.
Attachments
Please. Does no one here know of the Rule of All Bass? These a laws based in physics, tested with real science, not just some mumbo-jumbo from the idiotic masses. The very easy to grasp "rule of thumb" is that a 10 inch speaker at low frequencies sounds best if your ears are ten feet away from the woofer. Naturally, a 15 inch woofer sounds beat if you are 15 feet away from the speaker. This is the basic Pysical pricipal that drives companies such as Bose to construct speaker cabinets that channel the speaker down a labrinthian tunnel before it exits the speaker enclosure. This is also why you can not possibly produce "Blocks Travelling Bass" with 50 ten inch woofers, no matter the quality of the speaker, or the amount of amplitude. So that is why the sound you strive to achieve is such a personnal choice. Because unless you have a 32 foot RV, those 15 inch woofers will always sound better about 20 feet in FRONT of your car. This impresses the judges, and attracts hoes, but, if you want the best possible sound for YOU, sitting in the drivers seat, Then the best sound can be engineered by using high-excursion tens on the back deck, and a single 12 in the trunk, facing the rear of the car. If you really want to get it right, bridge an old-school Punch 150 to run the 15". And then mount four of the best tweeters you can afford at ear level, at the four corners of your interior. Add one more pair of 8 inch midrange speakers to the door panels, and you will then have the perfect sounding system. You wil have impressive blocs-travelling bass, crunching bass guitar from the 10"'s, ear-splitting vocals from the 8" mids, and to put the iceing on the cake, 200 watts split between four one-inch tweeters. So, with only a single 15" three amplifyers, two 10"'s, two 8"'s, and four 1" tweeters. This set-up will raise the hair on your neck with only nine speakers. It will sound excellent from the drivers seat, and produce enough bass to attract the right ladies. And best of all, you will then have not just another stereo system, but you will also have the kind of Class that only the smart and sensible people will respect. And of course, those are the kind of people you want in YOUR life, I know I do.
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