Hi,
The problem with those that don't know much is that they can talk
themselves into a lot of things without foreseeing the many pitfalls.
That review of that monitor is a poor excuse for a review, and
certainly doesn't explain the tradeoffs of using over 2cuft per
6.5" driver, how that can work in a sealed room, the fact
max low SPL will still be very low for two 4cuft boxes and
a lot more besides, as well as load of tosh about vented
boxes, which is just trotting out marketing speak.
f you think you can knock out a pair of CLD cabinets
just by guessing based on very limited information
be my guest to have a go. From what I know about
CLD its not remotely easy*, and tile loaded boxes go
back to the 60's and Gilbert Briggs, nothing new.
Knocking out a SOTA fully active 3 way isn't something
that can be achieved just by having the ambition to
want to try to do it, in fact IMO its a big hindrance.
As soon as you try to go all out all sorts of "decisions"
can be justified, but in cold reality make no real sense.
rgds, sreten.
* In fact most of what I've read is misinformed garbage.
Having researched and grasped the basics of CLD its a
very difficult technique to use in a louspeaker, though
not impossible, RLD is relatively much more simple.
FWIW the characteristics and thickness of the damping
layer are critical, too thick is poor, unlike RLD where
too thick is just overdoing it more than you need to.
The problem with those that don't know much is that they can talk
themselves into a lot of things without foreseeing the many pitfalls.
That review of that monitor is a poor excuse for a review, and
certainly doesn't explain the tradeoffs of using over 2cuft per
6.5" driver, how that can work in a sealed room, the fact
max low SPL will still be very low for two 4cuft boxes and
a lot more besides, as well as load of tosh about vented
boxes, which is just trotting out marketing speak.
f you think you can knock out a pair of CLD cabinets
just by guessing based on very limited information
be my guest to have a go. From what I know about
CLD its not remotely easy*, and tile loaded boxes go
back to the 60's and Gilbert Briggs, nothing new.
Knocking out a SOTA fully active 3 way isn't something
that can be achieved just by having the ambition to
want to try to do it, in fact IMO its a big hindrance.
As soon as you try to go all out all sorts of "decisions"
can be justified, but in cold reality make no real sense.
rgds, sreten.
* In fact most of what I've read is misinformed garbage.
Having researched and grasped the basics of CLD its a
very difficult technique to use in a louspeaker, though
not impossible, RLD is relatively much more simple.
FWIW the characteristics and thickness of the damping
layer are critical, too thick is poor, unlike RLD where
too thick is just overdoing it more than you need to.
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Thanks for your insight. I will read more on Cld versus rld.
I certainly wasn't planning the box in a box cld model, more likely I will stick with my relatively thin but stiff (multibraced + cross braced) and well damped (thick bitumen) habits that seem to have worked with my other builds. I thought to combine this with a thin tile layer too, but clearly need to read more papers on the topic.
At least one advantage of my proposed project is a relatively small box and panels compared to some speakers.
PS would this be a less garbage filled review? (From Resolution)
www.spacoustics.co.uk/SP Acoustics SP1M.pdf
I certainly wasn't planning the box in a box cld model, more likely I will stick with my relatively thin but stiff (multibraced + cross braced) and well damped (thick bitumen) habits that seem to have worked with my other builds. I thought to combine this with a thin tile layer too, but clearly need to read more papers on the topic.
At least one advantage of my proposed project is a relatively small box and panels compared to some speakers.
PS would this be a less garbage filled review? (From Resolution)
www.spacoustics.co.uk/SP Acoustics SP1M.pdf
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If you want to stick with Scans and close c-c spacing, have a look at Scan-Speak 602010
See: Zaph|Audio
See: Zaph|Audio
Hi,
FWIW with a bluff sealed box intended to be placed near wall I'd go with :
H1659-08 U22REX/P-SL
And a carefully chosen very good tweeter than works best off axis, YMMV.
It has been shown for many years a good 2 way is far more cost effective
than a 3 way using cone drivers, unless the 3 way does a lot more bass.
rgds, sreten.
FWIW with a bluff sealed box intended to be placed near wall I'd go with :
H1659-08 U22REX/P-SL
And a carefully chosen very good tweeter than works best off axis, YMMV.
It has been shown for many years a good 2 way is far more cost effective
than a 3 way using cone drivers, unless the 3 way does a lot more bass.
rgds, sreten.
Sreten, thanks for that I will have a look at it.
I appreciate I probably know less than you have forgotten, and am naive to many of the problems I will face. I also completely understand the 'bitten off more than he can chew' viewpoint, and how this would make many of you much more experienced DIY'ers roll your eyes!
I also appreciate my proposition is certainly not good value for money. But I do think that making mistakes and challenging oneself is the best way to learn. I have already learnt a lot about RLD and CLD from your previous comments which stimulated further reading (the internet is an amazing place).
And I appreciate that one of the best techniques for minimising a 'noisy box' is the use of multiple, light, stiff internal braces that join 'resonating nodal areas' to non resonating regions - i.e. the middle of a side panel to the edge of the opposite side or to a corner where stiffness is maximum.
I also appreciate that sealed alignment is not necessarily the best route and certainly not the most efficient use of drivers, but it is something I am keen to try.
I plan on going active mainly because as long as I get the boxes right, I believe that with PC software based x-overs and dsp solutions, much of the problems of time alignment, phase correction, room correction, frequency response etc can be dealt with digitally.
Finally, although this might be a complete c*ck-up and I will probably make many mistakes along the way, I will learn, have fun and be able to recyle the drivers into any number of future projects, or if I get completely downhearted sell them on. So I am only potentially wasting my money on some MDF, hardwood braces, bitumen damping material, some fiberglass insulation and a couple cans of paint (and of course wasting my time and effort!), oh and maybe a few cheap tiles.....!
I appreciate I probably know less than you have forgotten, and am naive to many of the problems I will face. I also completely understand the 'bitten off more than he can chew' viewpoint, and how this would make many of you much more experienced DIY'ers roll your eyes!
I also appreciate my proposition is certainly not good value for money. But I do think that making mistakes and challenging oneself is the best way to learn. I have already learnt a lot about RLD and CLD from your previous comments which stimulated further reading (the internet is an amazing place).
And I appreciate that one of the best techniques for minimising a 'noisy box' is the use of multiple, light, stiff internal braces that join 'resonating nodal areas' to non resonating regions - i.e. the middle of a side panel to the edge of the opposite side or to a corner where stiffness is maximum.
I also appreciate that sealed alignment is not necessarily the best route and certainly not the most efficient use of drivers, but it is something I am keen to try.
I plan on going active mainly because as long as I get the boxes right, I believe that with PC software based x-overs and dsp solutions, much of the problems of time alignment, phase correction, room correction, frequency response etc can be dealt with digitally.
Finally, although this might be a complete c*ck-up and I will probably make many mistakes along the way, I will learn, have fun and be able to recyle the drivers into any number of future projects, or if I get completely downhearted sell them on. So I am only potentially wasting my money on some MDF, hardwood braces, bitumen damping material, some fiberglass insulation and a couple cans of paint (and of course wasting my time and effort!), oh and maybe a few cheap tiles.....!
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there's nothing wrong to build with less experience.
all of this recommendation just from individual pov, you may always have one and some principle that you develop after more builds.
since measurement tools are more affordable than ever, you can invest as little as $200 to learn to design speakers properly.
good drivers usually easier to work with, i have not use the illum mids, but everyone said they are one of the best.
concept is as good as concept. 3way have advantage of the ability to play louder with less distortion on lower freq than 2way, in principle i think thats the bottom line.
having a waveguide for cutoff freq @3khz is a waste, using smaller tweeter like hiquiphon will produce similar dispersion characteristics.
all of this recommendation just from individual pov, you may always have one and some principle that you develop after more builds.
since measurement tools are more affordable than ever, you can invest as little as $200 to learn to design speakers properly.
good drivers usually easier to work with, i have not use the illum mids, but everyone said they are one of the best.
concept is as good as concept. 3way have advantage of the ability to play louder with less distortion on lower freq than 2way, in principle i think thats the bottom line.
having a waveguide for cutoff freq @3khz is a waste, using smaller tweeter like hiquiphon will produce similar dispersion characteristics.
Thanks. One of the reasons for going from my current two way reflex monitors to a three way rather than another two way, was that I like to listen at pretty loud levels sometimes. My current monitors manage about 108 SPL at 1m, but going sealed obviously makes it a less efficient design, so the woofer and mid needed decent sensitivity, and I couldn't seem to find a sealed two way concept that could manage high SPL levels. The scan speak classic seemed ideal as it has a relatively high sensitivity for such a low fs and excellent extension in a sealed alignment, whilst the mid is also pretty sensitive for such a small driver and has excellent linear x-max. My reasoning might be faulty on this though of course!
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nope, you are on the right track.
not easy to find suitable woofer that can be good in small size sealed cabinet.
not easy to find suitable woofer that can be good in small size sealed cabinet.
Scan speak 22W8851
recommended cabinet 1: closed cabinet with 11,7 L volume from 67/42 Hz (-3dB/-8dB)
If you are going active then you could get flat to 40Hz probably.
Not cheap though.
Yours is very similar my upcoming active project. I have all the drivers. Just need the time!
R2904/7000
15M/4531
22W/8851
recommended cabinet 1: closed cabinet with 11,7 L volume from 67/42 Hz (-3dB/-8dB)
If you are going active then you could get flat to 40Hz probably.
Not cheap though.
Yours is very similar my upcoming active project. I have all the drivers. Just need the time!
R2904/7000
15M/4531
22W/8851
Now those are impressive woofers! I agree they would perform better than the 8" classic I am thinking of, but at another £100 more per driver that is probably a step too far! (I think I discounted them purely on that basis....) Plus my wife is OK with 33 litre cabinets, so I don't need to reduce volume down to ~12 L to increase WAF further!
I should be able to get an F3 of ~45hz with a Q around 0.7 with the classic, which is what I was aiming for, although I appreciate the x-max won't be as impressive as the 22W/8851. I expect the sealed alignment will provide some mechanical high pass properties to ameliorate.
I would have thought with those drivers, if you are going sealed you'll be able to get an incredible performance in a very compact box.
I should be able to get an F3 of ~45hz with a Q around 0.7 with the classic, which is what I was aiming for, although I appreciate the x-max won't be as impressive as the 22W/8851. I expect the sealed alignment will provide some mechanical high pass properties to ameliorate.
I would have thought with those drivers, if you are going sealed you'll be able to get an incredible performance in a very compact box.
http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Black Box_copy.pdf
Hi,
The above is a old school idea for compact sealed boxes
for good bass. You can model it in the free version of Basta!
Tolvan Data
rgds, sreten.
You can get a bigger driver than 8" into a sealed and well stuffed 33L box, up to 12".
Hi,
The above is a old school idea for compact sealed boxes
for good bass. You can model it in the free version of Basta!
Tolvan Data
rgds, sreten.
You can get a bigger driver than 8" into a sealed and well stuffed 33L box, up to 12".
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Do you mind if I ask why you're using what appears to be such a mish-mash of drivers? Have you already acquired the illuminator midrange?
The midrange driver you've spec'd is an amazing little unit, I looked at it before and was very tempted but could see trouble with finding the right drivers to integrate it with.
Also, the jump from full range to 3-way is massive, so unless you already have the midrange unit, or there's a particular reason to go 3-way, I'd be going 2-way personally.
How are you approaching crossovers? The opening post seems to imply an active xo, which makes life entirely different and more easy! - I know from experience that getting a 3-way crossover 'right' is very tedious
The midrange driver you've spec'd is an amazing little unit, I looked at it before and was very tempted but could see trouble with finding the right drivers to integrate it with.
Also, the jump from full range to 3-way is massive, so unless you already have the midrange unit, or there's a particular reason to go 3-way, I'd be going 2-way personally.
How are you approaching crossovers? The opening post seems to imply an active xo, which makes life entirely different and more easy! - I know from experience that getting a 3-way crossover 'right' is very tedious
Sreten - Thanks for the links - that looks very interesting - I will do more research!
Nannoo - Why three-way over two -way despite the complexities? - Well going active and possibly using computer based x-overs and DSP should simplify matters there.....hopefully. But as I have previously explained, I want to go sealed, and I want high clean Spl, with an F3 around 45hz. This is difficult to achieve with a 2-way sealed.
Why the mish-mash of drivers? Well I believe the mid-range driver is the most important one in a three way - the 300-3000hz range is the most important bit to get right. I want it to be sealed, and a cone rather than a dome, to get the dynamics and Spl I want, and I want it to cover as much of that range as possible.
So the 12MU is an ideal candidate for these requirements - it is sensitive for a midrange cone, covers that freq range quite well, has good x-max, and is highly regarded.
The other two drivers are then partly chosen to hopefully blend well with the mid, but also out of design nessesity - that mainly being size! I have to keep this 3-way sealed box as small as possible.
There are very few 8" drivers that will drop to 45hz in a sealed box below 35 litres volume. A 10" driver is too large (not enough WAF - as it needs a much wider and therefore more obvious box), and therefore apart from a few very expensive candidates the 21W/8555-00 seems by far the best option.
The tweeter choice is because of my chosen x-over points - I want the mid to cover up to 3khz, so C-C spacing is best kept as small as possible, I also want smooth on and off-axis response, so the SB29RDNC fits this bill nicely and at such a high crossover, should be more that capable of keeping up. I did consider the LD25X from CSS, too.
By the way I really welcome all these questions and thoughts, I only have my reasoning to go by, which might be completely illogical, or naive, and I fully realise I might be very, very wrong.
Nannoo - Why three-way over two -way despite the complexities? - Well going active and possibly using computer based x-overs and DSP should simplify matters there.....hopefully. But as I have previously explained, I want to go sealed, and I want high clean Spl, with an F3 around 45hz. This is difficult to achieve with a 2-way sealed.
Why the mish-mash of drivers? Well I believe the mid-range driver is the most important one in a three way - the 300-3000hz range is the most important bit to get right. I want it to be sealed, and a cone rather than a dome, to get the dynamics and Spl I want, and I want it to cover as much of that range as possible.
So the 12MU is an ideal candidate for these requirements - it is sensitive for a midrange cone, covers that freq range quite well, has good x-max, and is highly regarded.
The other two drivers are then partly chosen to hopefully blend well with the mid, but also out of design nessesity - that mainly being size! I have to keep this 3-way sealed box as small as possible.
There are very few 8" drivers that will drop to 45hz in a sealed box below 35 litres volume. A 10" driver is too large (not enough WAF - as it needs a much wider and therefore more obvious box), and therefore apart from a few very expensive candidates the 21W/8555-00 seems by far the best option.
The tweeter choice is because of my chosen x-over points - I want the mid to cover up to 3khz, so C-C spacing is best kept as small as possible, I also want smooth on and off-axis response, so the SB29RDNC fits this bill nicely and at such a high crossover, should be more that capable of keeping up. I did consider the LD25X from CSS, too.
By the way I really welcome all these questions and thoughts, I only have my reasoning to go by, which might be completely illogical, or naive, and I fully realise I might be very, very wrong.
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Sreten - the 'black box' speaker is very similar to my ideas/requirements only passive - Thank you! A great read.
Very similar decisions were made - width and height of the box were kept to absolute minimum and determined by woofer width and driver vertical spacing. My box design is the same criteria, but fortunately I manage a Q of ~0.7 without requiring the use of a series capacitor to modify the impedance curve. Very clever technique.
I agree, I would love a 12" to drive the base, but I am married...... However, fortunately, I will also have two sealed subs to assist, so total cone area will be OK.
Very similar decisions were made - width and height of the box were kept to absolute minimum and determined by woofer width and driver vertical spacing. My box design is the same criteria, but fortunately I manage a Q of ~0.7 without requiring the use of a series capacitor to modify the impedance curve. Very clever technique.
I agree, I would love a 12" to drive the base, but I am married...... However, fortunately, I will also have two sealed subs to assist, so total cone area will be OK.
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A narrow cabinet means that you will need baffle step compensation. If you do that by boosting the output of the woofer, or by attenuating everything over it, bass distortion will increase. If you want even lower bass distortion, you can go 3.5 with an extra woofer. The speaker will be a floor-stander with same width and depth.
0.5 woofer needs just a coil, then you can connect both to the same amplifier channel. Zaph used just a 3.6mH with ZDT 3.5
0.5 woofer needs just a coil, then you can connect both to the same amplifier channel. Zaph used just a 3.6mH with ZDT 3.5
Thanks - worth looking at, but I suspect floor stander is a no-go with the wife!
I am thinking baffle width will be approx 270mm, they are also to be positioned very close to the front wall.
I am thinking baffle width will be approx 270mm, they are also to be positioned very close to the front wall.
Two things:
Which modelling program are you using? I just ran the 18W8555 through Unibox. With stuffing just on the walls, it wants 26.6L for Qtc = .705 and F3 = 48.31Hz.
If you heavily stuff it, it only needs 18.3L for Qtc = .703 and F3 = 53Hz.
Just mentioning it.
Also, with such good drivers, I would be hesitant to place a narrow tube behind the mid. I'm sure I've read about a congested or boxy result although I could be wrong. Still I would try to work out a different type of chamber that gave it a little more room to breath. Or maybe a test box will tell you what's what.
It will be a shame also to place such good drivers so close to a front wall too, but what can you do........
Which modelling program are you using? I just ran the 18W8555 through Unibox. With stuffing just on the walls, it wants 26.6L for Qtc = .705 and F3 = 48.31Hz.
If you heavily stuff it, it only needs 18.3L for Qtc = .703 and F3 = 53Hz.
Just mentioning it.
Also, with such good drivers, I would be hesitant to place a narrow tube behind the mid. I'm sure I've read about a congested or boxy result although I could be wrong. Still I would try to work out a different type of chamber that gave it a little more room to breath. Or maybe a test box will tell you what's what.
It will be a shame also to place such good drivers so close to a front wall too, but what can you do........
Front wall I agree - no choice.....but I'll work on it!
I've used a few programs for the woofer sim and with 20hz fs, vast 134, and qts 0.31 have calculated about 32 litres for f3 of 45 and qtc of 0.7.
I'll check it again though when I get home. If I need less volume great! I'll be using a lot of bracing so that does eat into the volume a bit.
Regarding the mid enclosure I completely agree, and in fact i have started playing around with different 2 litre shapes like spheres, tubes, boxes, and funnels. As it will be inside the main enclosure, it doesn't have to look pretty!
I've used a few programs for the woofer sim and with 20hz fs, vast 134, and qts 0.31 have calculated about 32 litres for f3 of 45 and qtc of 0.7.
I'll check it again though when I get home. If I need less volume great! I'll be using a lot of bracing so that does eat into the volume a bit.
Regarding the mid enclosure I completely agree, and in fact i have started playing around with different 2 litre shapes like spheres, tubes, boxes, and funnels. As it will be inside the main enclosure, it doesn't have to look pretty!
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