Hey guys
I am aware this has been covered before in a previous post,
http://www.diyaudio.com/forums/showthread.php?s=&threadid=126430&highlight=cw2108
but unfortunately I am not too clear on the final application as I am pretty new to pro audio.
Ive built countless sealed sub enclosures for car applications, so my woodwooking skills are not too bad, but I have only grasped the theory of advanced box design for hifi. I have been reading this forum for a long time.
So... in my possession I have 8, yes.. 8 of these cw2108 jaycar drivers. I would like some advice on what enclosure design would best suit this speaker, possible volume and port sizes etc. I plan on using them for home theatre hifi and music (well obviously) mainly electronica like infected mushroom etc.
I plan on buying some soft dome tweeters from Altronics, as they are relatively cheap
(hopefully not too nasty) but im mearly matching the quality of the woofers 🙂
Anyhow, i was looking at this design
[URL=http://www.humblehomemadehifi.com/LBS.html[/URL]
i like the look so long as these woofers can handle a bass reflex design. I am not an audiophile by any means, but I do appreciate good overall sound from a system. PLus this box looks easy to make.
Oh and ill be attempting my own crossovers too..any quick advice on that would be great also
Any help is greatly appreciated
Kon
I am aware this has been covered before in a previous post,
http://www.diyaudio.com/forums/showthread.php?s=&threadid=126430&highlight=cw2108
but unfortunately I am not too clear on the final application as I am pretty new to pro audio.
Ive built countless sealed sub enclosures for car applications, so my woodwooking skills are not too bad, but I have only grasped the theory of advanced box design for hifi. I have been reading this forum for a long time.
So... in my possession I have 8, yes.. 8 of these cw2108 jaycar drivers. I would like some advice on what enclosure design would best suit this speaker, possible volume and port sizes etc. I plan on using them for home theatre hifi and music (well obviously) mainly electronica like infected mushroom etc.
I plan on buying some soft dome tweeters from Altronics, as they are relatively cheap
(hopefully not too nasty) but im mearly matching the quality of the woofers 🙂
Anyhow, i was looking at this design
[URL=http://www.humblehomemadehifi.com/LBS.html[/URL]
i like the look so long as these woofers can handle a bass reflex design. I am not an audiophile by any means, but I do appreciate good overall sound from a system. PLus this box looks easy to make.
Oh and ill be attempting my own crossovers too..any quick advice on that would be great also
Any help is greatly appreciated
Kon
Hi Kon, unfortunately the links don't go to the tweeter you picked, BUT- most of those cheap Altronics tweeters have quite high resonant frequencies (Fs) and crossing to a 6inch should be done quite low.
8 midwoofers YES? so 4 in each box?
Have a quick read through Joe Rasmussens thread on the "Elsinores"
General rule of thumb is to cross the tweeter at least 1 1/2 octaves above Fs and 2 octaves is better.
Looking at my 2003 catalogue, that drive has a dip of about 6dB at 1K, and rolls off sharply at 3K, so a first order with a zobel at around 2.5/3K should work. but if you use a cheaper tweeter you'll probably need a third order XO high pass.
High Qts driver ( 0.558 ) but low Vas 15.2litres
Please note these are Jaycar specs and therefore fuzzy.
You can get a pair of tallish boxes using the full width of a 1220 sheet of chipboard or MDF with a total internal volume between 60 and 100 litres, and then stuff loosely with your choice of fill/ fibreglass or polyester
8 midwoofers YES? so 4 in each box?
Have a quick read through Joe Rasmussens thread on the "Elsinores"
General rule of thumb is to cross the tweeter at least 1 1/2 octaves above Fs and 2 octaves is better.
Looking at my 2003 catalogue, that drive has a dip of about 6dB at 1K, and rolls off sharply at 3K, so a first order with a zobel at around 2.5/3K should work. but if you use a cheaper tweeter you'll probably need a third order XO high pass.
High Qts driver ( 0.558 ) but low Vas 15.2litres
Please note these are Jaycar specs and therefore fuzzy.
You can get a pair of tallish boxes using the full width of a 1220 sheet of chipboard or MDF with a total internal volume between 60 and 100 litres, and then stuff loosely with your choice of fill/ fibreglass or polyester
I used the CW2108s paired with CW2142s as a 2.5 way in 50L cabs tuned to ~40Hz (I'm at work, so numbers are only ballpark...)
CW2108s - respond nicely up to ~4KHz and fall off rapidly, like a good polycone should; In fact I'm running these without any crossover parts on the CW2108s
at the low end Fs is higher than Jaycar's specs (surprise surprise) but they model well in an EBS alignment; downside is they can't handle low end power very well at all, but if you've got 4/side they may be OK, depending on how loud you play. Otherwise I think they're a good mid driver.
I'll look out my measurements tonight if I remember when I get home
pics & more details here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=106962&perpage=25&pagenumber=2
CW2108s - respond nicely up to ~4KHz and fall off rapidly, like a good polycone should; In fact I'm running these without any crossover parts on the CW2108s
at the low end Fs is higher than Jaycar's specs (surprise surprise) but they model well in an EBS alignment; downside is they can't handle low end power very well at all, but if you've got 4/side they may be OK, depending on how loud you play. Otherwise I think they're a good mid driver.
I'll look out my measurements tonight if I remember when I get home
pics & more details here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=106962&perpage=25&pagenumber=2
Peter is right if you want to cross over that high.
Alternatively, you could buy some decent cheap eight inch or ten inch woofers and possibly go 3-way, using the 6 as the mid-bass, or possibly a transmission line but I have no experience with that implementation.
Electronica does contain some serious synthesizer bass notes though, so the power handling down low probably isn't going to suit your particular needs.
High Qts such as those Jaycar drivers are usually used in either infinite baffle or TL speakers, but if Peter has had success with EBS ported alignments you can certainly try using a ported box
Alternatively, you could buy some decent cheap eight inch or ten inch woofers and possibly go 3-way, using the 6 as the mid-bass, or possibly a transmission line but I have no experience with that implementation.
Electronica does contain some serious synthesizer bass notes though, so the power handling down low probably isn't going to suit your particular needs.
High Qts such as those Jaycar drivers are usually used in either infinite baffle or TL speakers, but if Peter has had success with EBS ported alignments you can certainly try using a ported box
Thanks for you all your responses guys..
So from what Ive gathered, possibly getting an 8" driver would solve the lower frequency hole that these drivers have.
Now, please forgive me as im not as cluey as most of you guys on here,
so if I go for a 3 way system, as Moondog55 suggests, then will I need a zorbel filter arrangement just for the cw2108, and a normal 1st order crossover for both the woofer and tweeter? Or is a Zorbel style crossover the way to go for everything. I quickly read up these XO networks, so this is for smoothing out the resonate frequency of the particular driver and to keep the impedence curve constant?. What type of windows program can i use to work all this out..
Ive seen tables of data in which there are values of inductors and capacitors to marry up the crossover points. Is this the correct way in determining the crossover network?
Lets just say i go for two cw2108s in each cabinet, in a ported enclosure, (MTM ?) what would be the ideal volume of each enclosure, (these drivers are probably not meant for bass reflex) but could yield better bass response as compared to sealed.
Im sorry but I am a little over my head but i am willing to learn the details. Sorry for the torrent of questions.
From what ive read on here my knowledge level is at around 1/10 😕
Thanks
So from what Ive gathered, possibly getting an 8" driver would solve the lower frequency hole that these drivers have.
Now, please forgive me as im not as cluey as most of you guys on here,
so if I go for a 3 way system, as Moondog55 suggests, then will I need a zorbel filter arrangement just for the cw2108, and a normal 1st order crossover for both the woofer and tweeter? Or is a Zorbel style crossover the way to go for everything. I quickly read up these XO networks, so this is for smoothing out the resonate frequency of the particular driver and to keep the impedence curve constant?. What type of windows program can i use to work all this out..
Ive seen tables of data in which there are values of inductors and capacitors to marry up the crossover points. Is this the correct way in determining the crossover network?
Lets just say i go for two cw2108s in each cabinet, in a ported enclosure, (MTM ?) what would be the ideal volume of each enclosure, (these drivers are probably not meant for bass reflex) but could yield better bass response as compared to sealed.
Im sorry but I am a little over my head but i am willing to learn the details. Sorry for the torrent of questions.
From what ive read on here my knowledge level is at around 1/10 😕
Thanks
That's OK as I'm probably only a 2/10 on that scale, very steep learning curve for me.
If you are talking about the mid-range cavity then a small sealed box is all you need for the CW2108, if it is being used as a mid-range.
3-way systems are harder to get right but offer better power handling, and IMO, a clearer mid-range.
While I like 8inch woofers, I usually use them in pairs, all I can say is for bass: bigger is better ;-)
Zobels ( also called conjugate circuits ) are used to flatten the impedance curve of the driver so that the components used in the XO work correctly, as you have surmised correctly.
Crossover slopes need to be worked out for each combination of drivers, there isn't a single rule that works for everyone with every combination of drivers.
Perhaps, as a general rule though , the louder and longer you play your music, the steeper the XO slopes need to be to protect the mid-range and tweeters from over excursion.
If this is your first speaker perhaps getting some chipboard and making a pair of sealed boxes of about 15 litres, using one of those cheaper Mylar tweeters, and just play with various XOs.
Use two binding posts on the box and make your crossovers on a big bit of peg-board outside of the box.
If you are talking about the mid-range cavity then a small sealed box is all you need for the CW2108, if it is being used as a mid-range.
3-way systems are harder to get right but offer better power handling, and IMO, a clearer mid-range.
While I like 8inch woofers, I usually use them in pairs, all I can say is for bass: bigger is better ;-)
Zobels ( also called conjugate circuits ) are used to flatten the impedance curve of the driver so that the components used in the XO work correctly, as you have surmised correctly.
Crossover slopes need to be worked out for each combination of drivers, there isn't a single rule that works for everyone with every combination of drivers.
Perhaps, as a general rule though , the louder and longer you play your music, the steeper the XO slopes need to be to protect the mid-range and tweeters from over excursion.
If this is your first speaker perhaps getting some chipboard and making a pair of sealed boxes of about 15 litres, using one of those cheaper Mylar tweeters, and just play with various XOs.
Use two binding posts on the box and make your crossovers on a big bit of peg-board outside of the box.
That is from Sreten in response to Peters original query on these drivers.
So 3-way should be feasible using a single inductor of the right value if you can find a driver with a smooth roll-off, or as an alternative use a plate amp for the woofer and run as sub + mid/tweeter.
Re:" need a zorbel filter arrangement just for the cw2108, and a normal 1st order crossover for both the woofer and tweeter? Or is a Zorbel style crossover the way to go for everything.
I quickly read up these XO networks, so this is for smoothing out the resonate frequency of the particular driver and to keep the impedence curve constant?. '
No, you don't need a zobel, and they aren't for smoothing out the resonant freq (that's a car audio myth...), The basics (You've got to understand the rules before you can break them 🙂
http://sound.westhost.com/lr-passive.htm
"Ive seen tables of data in which there are values of inductors and capacitors to marry up the crossover points. Is this the correct way in determining the crossover network?" No, you need to use actual impedance values at your xover freq, calculators here will help:
http://ccs.exl.info/calc_cr.html#second
"Lets just say i go for two cw2108s in each cabinet, in a ported enclosure, (MTM ?) what would be the ideal volume of each enclosure, " - download Winisd and use that to figure it out:
http://www.linearteam.dk/default.aspx?pageid=winisdpro
'Sorry for the torrent of questions.' - don't be, ask heaps 😉
I quickly read up these XO networks, so this is for smoothing out the resonate frequency of the particular driver and to keep the impedence curve constant?. '
No, you don't need a zobel, and they aren't for smoothing out the resonant freq (that's a car audio myth...), The basics (You've got to understand the rules before you can break them 🙂
http://sound.westhost.com/lr-passive.htm
"Ive seen tables of data in which there are values of inductors and capacitors to marry up the crossover points. Is this the correct way in determining the crossover network?" No, you need to use actual impedance values at your xover freq, calculators here will help:
http://ccs.exl.info/calc_cr.html#second
"Lets just say i go for two cw2108s in each cabinet, in a ported enclosure, (MTM ?) what would be the ideal volume of each enclosure, " - download Winisd and use that to figure it out:
http://www.linearteam.dk/default.aspx?pageid=winisdpro
'Sorry for the torrent of questions.' - don't be, ask heaps 😉
Hi Konman,
My idea would be to run thosw 8 drivers as OB, with 6.5" midrange.
Now, just in case you can't make up your mind... I'm happy to buy them 😀
My idea would be to run thosw 8 drivers as OB, with 6.5" midrange.
Now, just in case you can't make up your mind... I'm happy to buy them 😀
Ran a quick sim in Unibox, good LF response seems to be ~ 25L tuned to 44Hz, so that's 50L for 2, 100L for 4 - a bit big...???
Moondog's suggestion is good, handle the low end with a cheap woofer such as Jaycar 8”woofer :
http://www.jaycar.com.au/productVie...AT&SUBCATID=396
(IIRC that needs 40-50L), and use the 2108s MTM in a small sealed enclosure (~6L) from say 150Hz up
I'd start with really simple xovers - 1st order L only on the 8", add a cap in series with the MTM if you get LF distortion at the levels you play at...
A pair in a ported box would probably be OK by themselves (with tweeter) for your rear HT speakers
Moondog's suggestion is good, handle the low end with a cheap woofer such as Jaycar 8”woofer :
http://www.jaycar.com.au/productVie...AT&SUBCATID=396
(IIRC that needs 40-50L), and use the 2108s MTM in a small sealed enclosure (~6L) from say 150Hz up
I'd start with really simple xovers - 1st order L only on the 8", add a cap in series with the MTM if you get LF distortion at the levels you play at...
A pair in a ported box would probably be OK by themselves (with tweeter) for your rear HT speakers
I have had a very good result using a sealed box with a 12inch driver from Altronics, but for some reason the price has jumped on those and while they have good deep bass they are not what I would call cheap.
Now having said that I cannot find that driver on the website, must have been deleted in the last 24hrs.
I have heard some good things about the cheap Jaycar 8inch woofer
8" Paper Cone Woofer
The new series of Response woofers are excellent for replacement or for new speaker design constructions. Not only are they price competitive and perform very well, but they also look fantastic!
The concave treated paper cone matched with rubber surround provides smooth overall response. Equipped strong steel frame baskets, high power magnet and voice coils, these drivers will produce massive quantities of clean bass output for any musical application.
Specifications:
• Nominal impedance: 8 ohms
• Power nominal: 90WRMS
• Frequency response: 38Hz - 4.5kHz
• Sensitivity:89dB (1W@1m)
• Qms: 1.458
• Qes:0.426
• Qts: 0.33
• Fs: 28.14Hz
Dimensions:
• A= 220
• B= 212
• C= 182
• D= 92
http://www.jaycar.com.au/products_uploaded/CW2196 frequency.pdf
http://www.jaycar.com.au/products_uploaded/CW2196(W-220PII)%20parameter.pdf
At $140 for 4 of them though it starts to get expensive, I have a couple of the old Jaycar polycone woofers here, suitable for 40litre sealed stuffed box, $55- each plus P+P, if you are interested
Now having said that I cannot find that driver on the website, must have been deleted in the last 24hrs.
I have heard some good things about the cheap Jaycar 8inch woofer
8" Paper Cone Woofer
The new series of Response woofers are excellent for replacement or for new speaker design constructions. Not only are they price competitive and perform very well, but they also look fantastic!
The concave treated paper cone matched with rubber surround provides smooth overall response. Equipped strong steel frame baskets, high power magnet and voice coils, these drivers will produce massive quantities of clean bass output for any musical application.
Specifications:
• Nominal impedance: 8 ohms
• Power nominal: 90WRMS
• Frequency response: 38Hz - 4.5kHz
• Sensitivity:89dB (1W@1m)
• Qms: 1.458
• Qes:0.426
• Qts: 0.33
• Fs: 28.14Hz
Dimensions:
• A= 220
• B= 212
• C= 182
• D= 92
http://www.jaycar.com.au/products_uploaded/CW2196 frequency.pdf
http://www.jaycar.com.au/products_uploaded/CW2196(W-220PII)%20parameter.pdf
At $140 for 4 of them though it starts to get expensive, I have a couple of the old Jaycar polycone woofers here, suitable for 40litre sealed stuffed box, $55- each plus P+P, if you are interested
ok
now im getting excited about this project..
From what you guys have been saying, and the general consensus that im getting from everyone is to get a bass woofer and use these other ones as mids..
OK.. this is what i want to do, purchase the CW2196 8" jaycar woofers (only 2, wife will kill me) and create a three way system... yes, im liking this alot.
Then use remaining 2 in a home theatre surround satelite speaker setup, so that would be 25 litre boxes...
ok... ive made up my mind for the main front two speakers...
CW2196 8" woofer
CW2108 6" mid
CT2023 ribbon tweeter or CT2005 dome tweeter
and rear channels
CW2108 6"
CT2023 ribbon tweeter or CT2005 dome tweeter
As PeteMcK has suggested, Im going to start with simple crossovers, 1st order with simple inline inductors with caps..
Thanks Moondog for your help also.. all these responses are honestly extrememly valuable to me. Im going to make the crossovers outside of the box for now as im in no doubt going to make a mistake somewhere.
So I guess off I go (yet again) to bunnings for some MDF. So in amoungst building my outdoor pizza oven, ill slowly chip away at this newly found project.
Ill take some progress photos and show you guys how i go with these.
Thanks again, and Ill be posting soon
Cheers!
🙂 🙂
now im getting excited about this project..
From what you guys have been saying, and the general consensus that im getting from everyone is to get a bass woofer and use these other ones as mids..
OK.. this is what i want to do, purchase the CW2196 8" jaycar woofers (only 2, wife will kill me) and create a three way system... yes, im liking this alot.
Then use remaining 2 in a home theatre surround satelite speaker setup, so that would be 25 litre boxes...
ok... ive made up my mind for the main front two speakers...
CW2196 8" woofer
CW2108 6" mid
CT2023 ribbon tweeter or CT2005 dome tweeter
and rear channels
CW2108 6"
CT2023 ribbon tweeter or CT2005 dome tweeter
As PeteMcK has suggested, Im going to start with simple crossovers, 1st order with simple inline inductors with caps..
Thanks Moondog for your help also.. all these responses are honestly extrememly valuable to me. Im going to make the crossovers outside of the box for now as im in no doubt going to make a mistake somewhere.
So I guess off I go (yet again) to bunnings for some MDF. So in amoungst building my outdoor pizza oven, ill slowly chip away at this newly found project.
Ill take some progress photos and show you guys how i go with these.
Thanks again, and Ill be posting soon
Cheers!
🙂 🙂
The dome can probably be crossed over a lot lower, start with the woofer first order and if that doesn't give you enough attenuation go to second, if you are buying inductors at Jaycar perhaps the 5.6mH laminate which will give 1st order at around 230Hz, then you can use the same value inductor to make second order on the mid, this will allow you to take advantage of the "buy 4 " price, and using a "Linkwitz-Riley " slope shoudd be enough to allow the mid to play down that low (( Hopefully ))
Don't forget to make allowances for the DCR of the inductors when calculating box size and if going sealed a moderate "Q" gives tighter bass, a high "Q" ( ie a smaller box ) gives a peaked bass response, aim for a "Q" of between 8 and 9 and you should be OK.
Zobel calculators abound on the web, probably worth doing on the woofer, by playing around with values in the conjugate you sometimes wind up with what is called "Strange" second order circuits, and resistors are cheaper than other components.
Regards Ted
PS: Don't stop asking questions, sometimes I think I have a frustrated teacher living inside my head.
Don't forget to make allowances for the DCR of the inductors when calculating box size and if going sealed a moderate "Q" gives tighter bass, a high "Q" ( ie a smaller box ) gives a peaked bass response, aim for a "Q" of between 8 and 9 and you should be OK.
Zobel calculators abound on the web, probably worth doing on the woofer, by playing around with values in the conjugate you sometimes wind up with what is called "Strange" second order circuits, and resistors are cheaper than other components.
Regards Ted
PS: Don't stop asking questions, sometimes I think I have a frustrated teacher living inside my head.
Ive quickly done up a crossover network for this design.
I was thinking of making the 6" mids run off a bandpass crossover config, but then read that to only use bandpass when the frequency difference is 20 times the crossover frequency or 2 frequency decades. So i canned that idea as the high pass would be 230hz and low pass would be around 4000hz. (going by the advice you two have given)
If I run two 6 "mids together in paralell, this would create a 4 ohm load. Would this matter at all or would the changing the values of the coils and caps even this out ie. insert a 4ohm load into a crossover calculator instead of 8 ohm. I presume the crossover would even out the load with the right values.
Anyway, have a quick look at the attatched file. See if that network is good to go so i can start ordering the parts 🙂
I was thinking of making the 6" mids run off a bandpass crossover config, but then read that to only use bandpass when the frequency difference is 20 times the crossover frequency or 2 frequency decades. So i canned that idea as the high pass would be 230hz and low pass would be around 4000hz. (going by the advice you two have given)
If I run two 6 "mids together in paralell, this would create a 4 ohm load. Would this matter at all or would the changing the values of the coils and caps even this out ie. insert a 4ohm load into a crossover calculator instead of 8 ohm. I presume the crossover would even out the load with the right values.
Anyway, have a quick look at the attatched file. See if that network is good to go so i can start ordering the parts 🙂
Attachments
I'd run the 6" mids in series - I think that'll give a better match to the sensitivity of the 8" & make BSC easier
No, the crossover won't 'even out the load'
What Impedance values did you use to calculate your part values? - we can't check if they're right if we don't know that.
Re: your xover diagram, I'd make it even simpler, - omit the C on the woofer, this lets you use varying the L to deal with BSC;
& also omit the L on the mids at first, the CW2108 drops off fast enough that you don't need it
You may need a resistor in series with the tweeter to adjust how bright it is, but try it without at first.
Also, how wide are you planning to make your cab? - need to know to calc the BSC freq.
(Excuse my terse replies - I'm at work and have to squeeze answers in while I can 😀 )
No, the crossover won't 'even out the load'
What Impedance values did you use to calculate your part values? - we can't check if they're right if we don't know that.
Re: your xover diagram, I'd make it even simpler, - omit the C on the woofer, this lets you use varying the L to deal with BSC;
& also omit the L on the mids at first, the CW2108 drops off fast enough that you don't need it
You may need a resistor in series with the tweeter to adjust how bright it is, but try it without at first.
Also, how wide are you planning to make your cab? - need to know to calc the BSC freq.
(Excuse my terse replies - I'm at work and have to squeeze answers in while I can 😀 )
I find that the wider the range that the mid plays the better sounding the final speaker, the advice I've read is to have the mids play a MINIMUM of 3 octaves, so 250 to 4000 works, I agree with peter in this instance, try it with no inductor at the top of the band pass, just cut the low frequencies with a second order. Add an inductor at the top later if needed.
If you decide to run the mids in series it will double the inductor value needed ( and halve the value of the capacitor of course ) so costs increase rapidly as high value inductors wound with large wire aren't cheap.
However; I have found that inductors in the return path to ground can be of a relatively high DCR without too much effect on the sound.
Jaycar have a 9mH laminate core you could try that value in your calculations.
Matching sensitivity's is why i recommended two woofers, the alternative is to just use 1 of those 6inch, that actually gives you the classic configuration WMT layout.
have you downloaded any programs yet?? To help you work out box sizes and such??
regards
Ted
If you decide to run the mids in series it will double the inductor value needed ( and halve the value of the capacitor of course ) so costs increase rapidly as high value inductors wound with large wire aren't cheap.
However; I have found that inductors in the return path to ground can be of a relatively high DCR without too much effect on the sound.
Jaycar have a 9mH laminate core you could try that value in your calculations.
Matching sensitivity's is why i recommended two woofers, the alternative is to just use 1 of those 6inch, that actually gives you the classic configuration WMT layout.
have you downloaded any programs yet?? To help you work out box sizes and such??
regards
Ted