Hi all!
I have a question concerning needed volume for a driver. There is something I don't get, I read on the internet that floorstanding have a deeper bass response as it's bigger than bookshelves. At the same time there are many box volume calculator like this one: Speaker Box Enclosure Designer / Calculator using Vas, Fs, etc. and compute the optimal volume. I even see floorstanding design using internal chambers to respect that volume. So what's the difference of that volume being in a bookshelve vs a floorstanding?
Also tell me, what we want to achieve is a balanced speaker with a uniform freq. response... right? If there would be more bass response that mean low freq would be louder in db..in a SPL graph???
Thanks!!!
I have a question concerning needed volume for a driver. There is something I don't get, I read on the internet that floorstanding have a deeper bass response as it's bigger than bookshelves. At the same time there are many box volume calculator like this one: Speaker Box Enclosure Designer / Calculator using Vas, Fs, etc. and compute the optimal volume. I even see floorstanding design using internal chambers to respect that volume. So what's the difference of that volume being in a bookshelve vs a floorstanding?
Also tell me, what we want to achieve is a balanced speaker with a uniform freq. response... right? If there would be more bass response that mean low freq would be louder in db..in a SPL graph???
Thanks!!!
If it is to be a bookshelf size and you have book shelf to place it it on, you most often do. If you have to place them on the floor, you may use chambers to ensure the correct volume and raise the drivers so they are closer to ear level.
As far as extra bass, the room along with the speaker placement plays a large roll in how the direct and reflected waves arrive at your ear. Together they will add to the perceived bass, but where they arrive at your ear out of phase, there is a cancelling of the perceived bass.
Every room is different and you have to find the right location in your own environment. Often the so called right location is more how you personally like the sound than achieving accurate reproduction.
As far as extra bass, the room along with the speaker placement plays a large roll in how the direct and reflected waves arrive at your ear. Together they will add to the perceived bass, but where they arrive at your ear out of phase, there is a cancelling of the perceived bass.
Every room is different and you have to find the right location in your own environment. Often the so called right location is more how you personally like the sound than achieving accurate reproduction.
Hey! Thanks for the reply.
So Cal, you said that we use chambers inside floorstanding to ensure the right volume. So here are my questions:
Should we aim to have a balanced SPL curve in speaker construction?
If we use the same driver and same volume why many persons are saying that floorstanding have more bass response?
I see many floorstanding with 2 woofers ex. the kits bellow. What's the purpose?
Scan-Speak Ultimate Revelation, 2way Kit Pair w/ 2x15W/8530K01 & 9700
So Cal, you said that we use chambers inside floorstanding to ensure the right volume. So here are my questions:
Should we aim to have a balanced SPL curve in speaker construction?
If we use the same driver and same volume why many persons are saying that floorstanding have more bass response?
I see many floorstanding with 2 woofers ex. the kits bellow. What's the purpose?
Scan-Speak Ultimate Revelation, 2way Kit Pair w/ 2x15W/8530K01 & 9700
Due to Hoffman's Iron law (you can have low bass, small cabinet or high efficiency, pick two) larger volume speakers can go lower or be louder. Floorstanders are usually larger and thus can potentially go louder or lower than a bookshelf. Sometimes a designer makes a bookshelf with an integral stand, and this will not garner the merits of a larger cabinet volume. It does mean that the designer can more finely control the height the speakers are finally located at - they will make an assumption about how high your ears are when seated and adjust box height to point the design axis at that.
Speakers with multiple drivers often do it to be able to go louder, and also for pattern control. The MTM has a symmetrical directivity pattern perpendicular to the baffle, whereas a speaker with one woofer might have a nonsymmetric pattern at a different angle to the baffle.
Most people believe a balanced frequency response is a good goal. Floyd toole at the NRC in canada developed a series of tests that show that listeners prefer flat frequency response with smoothly narrowing directivity.
Here is a speaker with a textbook "good" response.
SoundStage! Measurements - Energy Connoisseur C-3 Loudspeakers (6/2002)
Here is one with a colored response.
SoundStage! Measurements - Talon Audio Khorus Loudspeakers (11/2000)
Here is one that is fine above 1kHz, but has problems in the bass and lower midrange
SoundStageNetwork.com | SoundStage.com - NRC Measurements: Vivid Audio B1 Loudspeakers
Many more here:
SoundStageNetwork.com | SoundStage.com - SoundStageNetwork.com | SoundStage.com
Speakers with multiple drivers often do it to be able to go louder, and also for pattern control. The MTM has a symmetrical directivity pattern perpendicular to the baffle, whereas a speaker with one woofer might have a nonsymmetric pattern at a different angle to the baffle.
Most people believe a balanced frequency response is a good goal. Floyd toole at the NRC in canada developed a series of tests that show that listeners prefer flat frequency response with smoothly narrowing directivity.
Here is a speaker with a textbook "good" response.
SoundStage! Measurements - Energy Connoisseur C-3 Loudspeakers (6/2002)
Here is one with a colored response.
SoundStage! Measurements - Talon Audio Khorus Loudspeakers (11/2000)
Here is one that is fine above 1kHz, but has problems in the bass and lower midrange
SoundStageNetwork.com | SoundStage.com - NRC Measurements: Vivid Audio B1 Loudspeakers
Many more here:
SoundStageNetwork.com | SoundStage.com - SoundStageNetwork.com | SoundStage.com
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Good basic to med level loudspeaker design books:
Speaker Building 201, Ray Alden
Introduction to Loudspeaker Design, John L. Murphy
Link for reference reading material list:
The Speaker Building Bible - Techtalk Speaker Building, Audio, Video Discussion Forum
Speaker Building 201, Ray Alden
Introduction to Loudspeaker Design, John L. Murphy
Link for reference reading material list:
The Speaker Building Bible - Techtalk Speaker Building, Audio, Video Discussion Forum
It's a good design goal, but design doesn't end there. It is possible that you want a raised response from high-mids to highs on-axis, so that you have a balanced response slightly off-axis, for example.
Thanks a lot for your replies.
I did not know about the Hoffman's Iron law. Makes a lot of sense.
I am now thinking what can be done for my current bookshelve. Obviously, I won't be able to touch the enclosure volume. I am wondering if I can replace the woofer by one producing lower bass. I guess I'll have to compromise on the sensitivity. I curently have a VifaPL11WH09. The guy is suggesting this one.
What do you guys think?
Scan-Speak Discovery 12W/8524G00 ; 12W/8524G00 - Solen Electronique Inc.
I did not know about the Hoffman's Iron law. Makes a lot of sense.
I am now thinking what can be done for my current bookshelve. Obviously, I won't be able to touch the enclosure volume. I am wondering if I can replace the woofer by one producing lower bass. I guess I'll have to compromise on the sensitivity. I curently have a VifaPL11WH09. The guy is suggesting this one.
What do you guys think?
Scan-Speak Discovery 12W/8524G00 ; 12W/8524G00 - Solen Electronique Inc.
Sorry for my question but what loudspeakers are this???
I think it is a waste of resource, why want we to build large loudspeaker with poor WAF and use maybe only half the speaker volume???
So I guess the question is :
I know Hoff. iron law is saying that: efficiency = F3 x volume^3 but does that apply only while considering the same driver?
Let's say I am able to find a driver that is more efficient by 3db than the one I have on paper and with a smaller F3, would it be more sensitive in the same enclosure?
I know Hoff. iron law is saying that: efficiency = F3 x volume^3 but does that apply only while considering the same driver?
Let's say I am able to find a driver that is more efficient by 3db than the one I have on paper and with a smaller F3, would it be more sensitive in the same enclosure?
Probably, impossible to say without the parameters, find the specs of some suitable drivers and have a play with this, it will give you a good idea of what to expect mh-audio.nl - Home
Sorry for my question but what loudspeakers are this???
I think it is a waste of resource, why want we to build large loudspeaker with poor WAF and use maybe only half the speaker volume???
A large number of commercial floorstanders have internally partitioned off cavities -these can often be filled with dried sand, lead-shot or similar. While in some ways it might seem inefficient engineering, it can actually be quite practical. Some (many) prefer the appearance of an integrated enclosure to a physically smaller box sitting on a pair of stands. And since most loudspeaker stands aren't likely to win any awards as pieces of objet d'art, it's understandable. In the same way, it's not necessarily wasting resources -depending on implementation it can actually use fewer than a pair of standmounts with a pair of stands when you account for materials, finishing, packaging, shipping etc.
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Every driver has its own range of volumes that it is happy to live in. This dictates how big the speaker can be. If it is not large enuff to reach the floor the sides can be extended down to the floor creating an empty cavity — this should be fileld with something (sand, kitty litter…).
Also note that a tower speaker is often an ML-TL. It may look on the surface to be a reflex enclosure but it has different behaviour and has to be treated differently.
dave
Also note that a tower speaker is often an ML-TL. It may look on the surface to be a reflex enclosure but it has different behaviour and has to be treated differently.
dave
If you click on "calculators" at the top, a list comes up with different loudspeaker calculators on the left, I don't know how accurate they are, not very I wouldn't imagine, but it will give you an idea
I'd stick with the Vifas - you have them on hand, and in an appropriately designed enclosure, they should yield quite acceptable performance. Unless you're keen to make using any of a number of modeling programs part of your learning curve, I wouldn't be surprised if designs in any of the popular flavors haven't already had all the math done. Of course I'm famously lazy in that regard, but I'd imagine that a speaker design program that doesn't allow for different types of alignment / loading is probably worth passing by?
Personally, I always prefer a floor-stander for the reasons already listed above, and unless complicated internally, don't find them any harder to build than a bookshelf - the difference in material costs to do so is generally far less than a "decent sounding" pair of stands.
An iron law applies to all drivers.
See above. You need to start asking less general questions you have a chance at understanding the answers to.
So you have a PL woofer, how big of a box? what is the tuning frequency? what is the crossover? what is the tweeter? Why do you want to change the woofer? Why not just get a subwoofer?
The Scanspeak woofer is lower sensitivity and it has a sizeable peak at the top end that will have to be dealt with.
Here is a visualization of hoffman's iron law:
Vb vs F3 plotted for 4 different sensitivities: 84, 87, 90, 93 dB
Note that you can gain 3dB in sensitivity by increasing box size by 2, or by increasing F3 by 1.26 times. In order to have a lower F3 and a larger sensitivity, you must have a larger box.
This is what is meant by low F3, small box, high sensitivity, pick 2.
If you want high sensitivity and low F3, you need a big box
If you want a small box and a low F3, you need low sensitivity
If you want high sensitivity and a small box, you need a high F3.
Vb vs F3 plotted for 4 different sensitivities: 84, 87, 90, 93 dB
Note that you can gain 3dB in sensitivity by increasing box size by 2, or by increasing F3 by 1.26 times. In order to have a lower F3 and a larger sensitivity, you must have a larger box.
This is what is meant by low F3, small box, high sensitivity, pick 2.
If you want high sensitivity and low F3, you need a big box
If you want a small box and a low F3, you need low sensitivity
If you want high sensitivity and a small box, you need a high F3.
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Ok let's say I want : "A small box and a low F3, you need low sensitivity" How can I achieved this? I guess have to replace the woofer right? That's why I asked earlier if it would be possible to find a woofer of "better quality" to cope for the lost in sensitivity and get bass extension at the same time.
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