Hi All,
Can anyone introduce a cabinet (with dimension) for my Morel MW168 + MDT30. I tends to have a rich bass reproduction.
Also how to design the crossover for this system. By two ways of approach 1) Woofer direct connect 2) Through a passive component.
Analogy
Can anyone introduce a cabinet (with dimension) for my Morel MW168 + MDT30. I tends to have a rich bass reproduction.
Also how to design the crossover for this system. By two ways of approach 1) Woofer direct connect 2) Through a passive component.
Analogy
ckwong99 hi,
You should be able to simulate your box dimensions with a software like WinISD or other. Did you test one before? Maybe some one can give you the best box size for that speaker that would save you some time but not the fun for doing it.
Now for the xover, with your Morels you should be fine with this one I designed for Etons. Lpad is joining in the same thread. You should need a -2dB Lpad but there are other values there like a -1,5 dB Tweeter Lpad. You will test for the best flat sound (output) or the way you like. (I can't remember if you need this anyway because, besides there are values there for all the Lpads, you may not need one afterall if the xover filter takes that into account in the first place.)
(Your woofer is 88dB and your tweeter is 90dB) That's why you will need about -2dB pad on the tweeter. Is this Ok?
Have fun.
http://www.diyaudio.com/forums/showthread.php?postid=863905#post863905
Parts List:
Capacitors
C1 = 18 uF
C2 = 6.8 uF
Inductors
L1 = 0.91 mH
L2 = 0.35 mH
Resistors
R = n.a.
R1 = n.a.
R2 = n.a.
http://www.diyaudio.com/forums/attachment.php?s=&postid=863905&stamp=1141756525
You should be able to simulate your box dimensions with a software like WinISD or other. Did you test one before? Maybe some one can give you the best box size for that speaker that would save you some time but not the fun for doing it.
Now for the xover, with your Morels you should be fine with this one I designed for Etons. Lpad is joining in the same thread. You should need a -2dB Lpad but there are other values there like a -1,5 dB Tweeter Lpad. You will test for the best flat sound (output) or the way you like. (I can't remember if you need this anyway because, besides there are values there for all the Lpads, you may not need one afterall if the xover filter takes that into account in the first place.)
(Your woofer is 88dB and your tweeter is 90dB) That's why you will need about -2dB pad on the tweeter. Is this Ok?
Have fun.
http://www.diyaudio.com/forums/showthread.php?postid=863905#post863905
Parts List:
Capacitors
C1 = 18 uF
C2 = 6.8 uF
Inductors
L1 = 0.91 mH
L2 = 0.35 mH
Resistors
R = n.a.
R1 = n.a.
R2 = n.a.
http://www.diyaudio.com/forums/attachment.php?s=&postid=863905&stamp=1141756525
Inductor said:
Hi,
Generally its not unless you like speakers with no baffle step compensation.
Hardly a "rich" alignment. BSC designed mid/treble level is around 84dB.
🙂/sreten.
sreten said:
Also it depends in the room you are, the position of the baffle in relation to the floor and on the internal resistance of L. (And on the size and position of woofer on the bafle). How much do you use on your bafflestep? 4dB's? (88-84). At what frequency output, <600Hz? This have little to do with the xover frequency of 2000Hz and up I guess. Or is it something else?
Thanks to your reply.
Actually, I tired to calculate the cabinet size but some parameter I can't understand. As a end user I would like my spk have smooth response between 50 to 20k Hz.
http://www.partsexpress.com/resources/pebox.html
Above is my calculation program obtained from partsexpress. It told me what dimension of cabinet but only input the part number. My woofer item number is (297-030) and the optimal size is 1.29 cu ft with 21 x 13 x 8 inches. Not sure this program accuracy and how to verify it ?
The x-over someone told me use 3-4k Hz. Due to this woofer is dual coil for mid-bass range type. How do you think ?
I will use the vented type cabinet because I tends to like a rich bass. In additional, my listening area around 9x10 feet so i intend to locate my spk close near the wall. therefore the air flow hole must be put at baffle (front side of the cabinet). I am not sure where to open the air hole at the baffle surface.
CK
Actually, I tired to calculate the cabinet size but some parameter I can't understand. As a end user I would like my spk have smooth response between 50 to 20k Hz.
http://www.partsexpress.com/resources/pebox.html
Above is my calculation program obtained from partsexpress. It told me what dimension of cabinet but only input the part number. My woofer item number is (297-030) and the optimal size is 1.29 cu ft with 21 x 13 x 8 inches. Not sure this program accuracy and how to verify it ?
The x-over someone told me use 3-4k Hz. Due to this woofer is dual coil for mid-bass range type. How do you think ?
I will use the vented type cabinet because I tends to like a rich bass. In additional, my listening area around 9x10 feet so i intend to locate my spk close near the wall. therefore the air flow hole must be put at baffle (front side of the cabinet). I am not sure where to open the air hole at the baffle surface.
CK
Morel MW168
http://www.partsexpress.com/pdf/297-030.pdf
Morel MDT30
http://www.partsexpress.com/pdf/277-015.pdf
ckwong99,
Hi, When you analyse this speakers they asked to be crossed at 2K or 2K5 and up. 3K or 4K is goood but not perfect unless you use another woofer. This tweeter Fs is at 700Hz (resonance) so that you want to go way from it (up) and with the right xover you will be fine (what is not the case w/ a 1. order xover). Second on the side of the woofer after 2k5 you start with transients on the frequency output what is telling you is to cross right there.
The duct position is not critical in the baffle.
One thing I dont't understand. You say it is a double voice coil "this woofer is dual coil" . Do you mean a double magnet?
This xover is a good start ( 2. order) but as with everything in life might need some adjustment. Notice the inverted tweeter because of 180º (90º+90º) inversion of phase in 2. order xovers.
Have fun.
http://www.partsexpress.com/pdf/297-030.pdf
Morel MDT30
http://www.partsexpress.com/pdf/277-015.pdf
ckwong99,
Hi, When you analyse this speakers they asked to be crossed at 2K or 2K5 and up. 3K or 4K is goood but not perfect unless you use another woofer. This tweeter Fs is at 700Hz (resonance) so that you want to go way from it (up) and with the right xover you will be fine (what is not the case w/ a 1. order xover). Second on the side of the woofer after 2k5 you start with transients on the frequency output what is telling you is to cross right there.
The duct position is not critical in the baffle.
One thing I dont't understand. You say it is a double voice coil "this woofer is dual coil" . Do you mean a double magnet?
This xover is a good start ( 2. order) but as with everything in life might need some adjustment. Notice the inverted tweeter because of 180º (90º+90º) inversion of phase in 2. order xovers.
To get to your point here, I am not sure a direct connect works with this type of woofer with a voice coil inductance of 0,62mH only. In this case you need a good passive xover. Unless you have an active xover and separeted amplis.
Have fun.
Sorry the woofer is double magnet design.
If I follow your x-over at 2K frequency connect to these two Morel units. So how should be the cabinet internal dimension when tunning frequency is 60 Hz ?
What the air flow duct diameter and length ?
Can anyone help me make this calculation. Thanks for your support in advance.
Hi Inductor , what the size of your cabinet and how much your Eton unit ? 5 or 7 inches ?
CK
If I follow your x-over at 2K frequency connect to these two Morel units. So how should be the cabinet internal dimension when tunning frequency is 60 Hz ?
What the air flow duct diameter and length ?
Can anyone help me make this calculation. Thanks for your support in advance.
Hi Inductor , what the size of your cabinet and how much your Eton unit ? 5 or 7 inches ?
CK
MW 168
recommended cabinet 1:
closed cabinet with 1,1 L volume
from 158/99 Hz (-3dB/-8dB)
recommended cabinet 2:
2,4 L volume bass reflex cabinet
with 65 cm long HP70 reflex tube
from 99/74 Hz (-3dB/-8dB).
(from the website: http://www.lautsprechershop.de/hifi/index_en.htm)
To simulate in WinISD is a work I like to do and also very personal in the way that you can choose output and size of cabinet.
recommended cabinet 1:
closed cabinet with 1,1 L volume
from 158/99 Hz (-3dB/-8dB)
recommended cabinet 2:
2,4 L volume bass reflex cabinet
with 65 cm long HP70 reflex tube
from 99/74 Hz (-3dB/-8dB).
(from the website: http://www.lautsprechershop.de/hifi/index_en.htm)
Sorry, I don't have cabinets for Etons.
Sorry ckwong, right now I don't have the time (exams) to simulate in WinISD or other software. I din't check the recommended cabinets sizes, so I am not in a position to help you in that either.
To simulate in WinISD is a work I like to do and also very personal in the way that you can choose output and size of cabinet.
ckwong, do you work with metric or imperial?
(About) the port, are you looking for a size DxL that you like? (or that you have available?)
When you make the box enclosure() Make sure the internal volume is without speakers vol., port volume, baffle thickness etc.
I used this specs instead.
Morel MW168
http://www.morelhifi.com/products/raw_woofers.html
Morel MDT30S
http://www.morelhifi.com/products/raw_tweeters.html
note: please ckwong, don't get confused because of the use of different softwares, each one has it's own number crunching so that results can be a little different. here is WinISD.
(About) the port, are you looking for a size DxL that you like? (or that you have available?)
When you make the box enclosure() Make sure the internal volume is without speakers vol., port volume, baffle thickness etc.
I used this specs instead.
Morel MW168
http://www.morelhifi.com/products/raw_woofers.html
Morel MDT30S
http://www.morelhifi.com/products/raw_tweeters.html
note: please ckwong, don't get confused because of the use of different softwares, each one has it's own number crunching so that results can be a little different. here is WinISD.
Attachments
Dear Coil,
I cordially thanks to your support.
I work with metric in all measurements. I am still looking for the port volume and thanks for your calculation.
I known the system designer would have different assumption themselves and come up their personal philosophy behind. So slight difference should be accepted.
There questions need your advice :
1) Now I can get the total volume of the vented box about 13.16L . So how to make this box with what dimension of it ?
2) I would like to make air hole in front of the speaker because it will be closed to the wall and it will be placed over the flat top cupboard. Where should it be open up at the baffle ?
3) In general, will the x-over design independent to the cabinet ? Thus, the x-over at any frequencies roll-off point should not effect to bass reflect in cabinet.
4) How to select a suitable roll-off point based on two units (tweeter & woofer) x-over network and they all work at vent type box ?
CK
I cordially thanks to your support.
I work with metric in all measurements. I am still looking for the port volume and thanks for your calculation.
I known the system designer would have different assumption themselves and come up their personal philosophy behind. So slight difference should be accepted.
There questions need your advice :
1) Now I can get the total volume of the vented box about 13.16L . So how to make this box with what dimension of it ?
2) I would like to make air hole in front of the speaker because it will be closed to the wall and it will be placed over the flat top cupboard. Where should it be open up at the baffle ?
3) In general, will the x-over design independent to the cabinet ? Thus, the x-over at any frequencies roll-off point should not effect to bass reflect in cabinet.
4) How to select a suitable roll-off point based on two units (tweeter & woofer) x-over network and they all work at vent type box ?
CK
ckwong99 said:
Is this number 13.16L your upper limit in the sizing of the box???
The golden rule is USED often. Let's say (for a small speaker) 33x24.5x18.5 (as an example only). In the old times we use to see the front panel 33x24.5. Now it's common the size 33x18.5, with a longer depth, 24.5.
When you determine a volume (in liters) for the enclosure that's the internal dimensions. Building material thickness (+speakers & port) will have to be taken into account when building it.
The position of the air hole in the front of the speaker is not critical. The lenght of the port is because you need at least one half (+/-) diameter between it and the back panel or insulation.ckwong99 said:
It can affect if you go low in frequency. In this case resonant frequencies are under 100Hz. xover design will take this in consideration for the case of the woofer, it's output etc.ckwong99 said:
The tweeter is independent of the vent type box. It does not affect it's own behaviour. You have to choose the xover frequency in a way that both woofer and tweeter will be merging well in there with the same final output.ckwong99 said:
Hi Coil,
Sorry for my typo error it should be 33L . But this volume is quite large for me .
Last Saturday I found a finished box internal volume about 18L vented type. Not sure what low frequency can it be sounded installed this driver ?
Till now all questions I can learn from here . I much appreciate to your DIY spirit.
CK
Sorry for my typo error it should be 33L . But this volume is quite large for me .
Last Saturday I found a finished box internal volume about 18L vented type. Not sure what low frequency can it be sounded installed this driver ?
Till now all questions I can learn from here . I much appreciate to your DIY spirit.
CK
Hi Coil,
According to your attached spectrum diagram found the -3db roll-off point at 50Hz and 2KHz.
So Is it a reason of the xover designed for 2K point ?
What is the tuning frequency (the roll-off level in -6db) ? How to determine it ?
The spectrum diagram highlighted 21.2 ohm and 74 Hz. What these two parameters used for ?
Thanks for your patience in advance :>
CK
According to your attached spectrum diagram found the -3db roll-off point at 50Hz and 2KHz.
So Is it a reason of the xover designed for 2K point ?
What is the tuning frequency (the roll-off level in -6db) ? How to determine it ?
The spectrum diagram highlighted 21.2 ohm and 74 Hz. What these two parameters used for ?
Thanks for your patience in advance :>
CK
ckwong99 said:
F3 is at 47KHz, yes.
The reason for xover point is the output of the speakers and it's behaviour at this frequencies around 2K5Hz. Let's check them again... (I'm using the Israeli charts not the american ones. There are two factories now because of a "spinoff", I don't know which are yours. www.morelhifi.com - is this ok?)
Fs on the woofer at 48Hz
Fs of the tweeter at 650Hz
So, now, if we do the xover at the required freq. (?) we
must be fine off the 650Hz. (I am not really doing it yet?!) It's also where (from around 2KHz and up) the tweeter is responding.
The woofer have a deep at 2K5 (good for a xover) and a limit at 4KHz but a lot of transients.
Tuning frequency is at 38Hz. Do you mean you want to know the formula? Or do you mean you want to know the formula for the xover components?
For your last question I am not sure (but it would help if you would use WinISD or another software, are you using it already?)
The graph for impedance is here (woofer/box + port)
18.5 Ohm@25Hz
21 Ohm@73Hz.
These two parameters are the resonance as in a Helmholz resonator due to the compliance of the enclosed air and the inductance of the air-mass in the vent.
Attachments
Sure www.morelhifi.com this is OK.
I want to know the formula of tuning frequency .
How I can select an optimal frequency point for the xover ?
CK
I want to know the formula of tuning frequency .
How I can select an optimal frequency point for the xover ?
CK
Helmholtz Resonance Calculator http://home.new.rr.com/trumpetb/audio/fboxjs.html
ckwong99, I hope this is what you are looking for.
ckwong99, I hope this is what you are looking for.
I don't know if I can answer that after what I've said. I think I can only speak for myself, personally is with experience (I know that's not the best answer). But for this to happend we have to choose the best ('optimal') speakers also of course, like you did.
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