Right now this Philips driver is sitting in an open baffle but space is limited in my room so I want to make some room. (so I can put more projects in de same place..haha).
There are lots of cabinet design out there and I get a bit confused by them so I decided to pick two possibilities. I Want to build a Closed box or MLTL, but I ran in to some questions.
The driver specs for the AD12202 are measured in a closed 80L box.
Now I know there is something like virtual volume due to filling the box with isolating damping material. So the question is do I build a 80L closed box and fill it up or do I make a smaller box which ends up with a virtual volume of 80L?
Than there is the MLTL enclosure. I can't simulate or design this myself unfortunately. On the Dutch forum the is a design for the AD12100 version but my driver has different specs.
The questions here are: Is there a need for a filter using the MLTL and maybe more important is this a better option than the closed one?
There are lots of cabinet design out there and I get a bit confused by them so I decided to pick two possibilities. I Want to build a Closed box or MLTL, but I ran in to some questions.
The driver specs for the AD12202 are measured in a closed 80L box.
Now I know there is something like virtual volume due to filling the box with isolating damping material. So the question is do I build a 80L closed box and fill it up or do I make a smaller box which ends up with a virtual volume of 80L?
Than there is the MLTL enclosure. I can't simulate or design this myself unfortunately. On the Dutch forum the is a design for the AD12100 version but my driver has different specs.
The questions here are: Is there a need for a filter using the MLTL and maybe more important is this a better option than the closed one?
Attachments
I owned a pair of 12202/M8. I used them in an open baffle. BUT!!! I did take measurements. Here they are, the average of the two drivers:
Re.........7.49 Ohms
Fs........43.74 Hz
Qts........0.456
Qes........0.55
Qms........2.665
Le..........0.189 mH (10k)
Mms.......35.19 g
Vas........135.7 L
Re.........7.49 Ohms
Fs........43.74 Hz
Qts........0.456
Qes........0.55
Qms........2.665
Le..........0.189 mH (10k)
Mms.......35.19 g
Vas........135.7 L
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Probably doesn't help you very much, but I'm putting together a BR (145L) for a pair of these.
http://www.diyaudio.com/forums/full-range/276766-philips-ad12202-m8-port-length.html
and
Philips AD12202-M8
http://www.diyaudio.com/forums/full-range/276766-philips-ad12202-m8-port-length.html
and
Philips AD12202-M8
The AD12202/M8 doesn't perform that well in a closed enclosure. Yes, precise bass but an f3 of 69Hz isn't that great. I've used the AD12202/M8 in a vented box with 85l, port 10cm diameter and 15cm length. Not ideal but that's what I had laying around at that time. Together with a supertweeter I used that combination for several years and enjoyed quite a lot. If you'd go for a vented enclosure I'd recommend you'd go for ~100l and a 10cm/d and 20cm length port though.
(comparison 80l cb vs. 100l br)
An externally hosted image should be here but it was not working when we last tested it.
(comparison 80l cb vs. 100l br)
Not finished yet (its a long way down on the to-do list atm)! The cut-down tannoy cabs ended up being 85x45x39 cm (HxWxD) (internal).
However, I've decided to build some similar in dimensions to those in the second link (~109x34x39~ish cm). I think they built to 147 or 148L with slot port. I'll reduce volume slightly to 145L and keep round port. The reason being is to move the driver up a bit higher - I don't like where it is placed in the tannoy cabs - I'm finding it too low and it will also reduce the overall footprint slightly (a bit narrower and shallower with an increase in height).
I vaguely remember finding a thread on MLTL - perhaps it is the one you are referring to?
Hi microdub, I like the the looks of the build of the 148L one out the second link. It that just a straightforward rectangular box? With this rectangular opening it looks like a TQWT or mltl.
An 100L version is tempting because you can create the looks of a big monitor, which I like very much. But if you guys say 140+Litre is even better I will go for that.
My question about "virtual volume" still stays open.. Because if this is the case I can build smaller with the same result.
R.
An 100L version is tempting because you can create the looks of a big monitor, which I like very much. But if you guys say 140+Litre is even better I will go for that.
My question about "virtual volume" still stays open.. Because if this is the case I can build smaller with the same result.
R.
Since I can't simulate cabinet designs I took your advice and designed around the mentioned parameters.
But there is a slight problem. The size for the port in your advices is 100MM, I would like to use PVC pipe and the standard size is 90MM outside with a 3mm thickness or 110MM outside with a 3.2mm thickness.
I would like your advice on this slight issue...
In the attachment is my design.. the internal volume of this design (without damping) is 104L With the mentioned port of 100mm diamater with a length of 200mm.
I hope I am not over asking but would like to read your comments.
R.
But there is a slight problem. The size for the port in your advices is 100MM, I would like to use PVC pipe and the standard size is 90MM outside with a 3mm thickness or 110MM outside with a 3.2mm thickness.
I would like your advice on this slight issue...
In the attachment is my design.. the internal volume of this design (without damping) is 104L With the mentioned port of 100mm diamater with a length of 200mm.
I hope I am not over asking but would like to read your comments.
R.
Uh, bjorno did two different length MLTL designs for you: http://www.diyaudio.com/forums/full-range/276766-philips-ad12202-m8-port-length.html#post4384576
GM
I must say I find it somewhat confusing that there seem to be so much different design/ideas fort the "same" result. Having the wood cut for a box of 104L I will first try that and hope for the best...
The port length for a 90mm (84) would be 18cm, am I correct that this results in a 15,5(ish) port length when using a 110 (103,6) pipe?
R.
The port length for a 90mm (84) would be 18cm, am I correct that this results in a 15,5(ish) port length when using a 110 (103,6) pipe?
R.
I was concentrating on building a BR with the gear I already had. I didn't pay too much attention to the HornResp output as I have never used Hornresp and, to be honest, had no idea what the output meant. At that stage, I hadn't looked it up as I was building a BR.
So, now that we have established that - I downloaded Hornresp, did some reading again and sat down with a pen and pencil and it (I think) clicked.
So (pls correct me if I'm wrong) two straight pipe TL (no folds!) were modeled....
Cab 1. Volume of 154.2L, H=133cm, internal cross sectional area area 1170cm2 (e.g. 30x39cm), port 170cm2 x 1.8 cm in length. Centre of driver 56.5cm from top.
Cab 2. Volume of ~102L, H=99.6cm, internal cross sectional area area 1170cm2 (e.g. 30x39cm), port 170cm2 x 14.6 cm in length. Centre of driver 40.4cm from top.
So, do the ports need to be right at the bottom of the cabinet (either bottom of sides or base with cab raised on legs) to make it a MLTL? Or would it otherwise be a badly tuned BR?
Anyway, I'm a newbie and just learnt something new.
Thanks GM for insisting.