Also, the cone is made of polypropylene - this should be durable enough to be left exposed without a mesh or wire netting covering it?
Hi, Any wire from bell wire up will be fine you don't need to spend alot of money on the cable unless you want to. The impedance of the wire will be so low compaired to the speaker that it won't be a limiting factor.
Construction wise depends on how hard you are going to use it. If you use 18mm MDF and then use lap joints which are glued along the whole length you sould be ok. If you are still concerend and want to make it even stronger you could use a bead of wood appox 1cm square glued in the inside along the seams.
If you really plan to go mad with it and play loud bass heavy tarcks for long periods of time you could put a pressure release vent in the cabinet. Basically this is an intentional hole in the box usually about 5mm in diameter stuffed with felt to resist air flow. This will preven the presure inside the box from getting to high. However it will mess up the bass alignment to a certain extent so I wouldn't do it unless your prime use for the speaker is PA.
A ploy cone will be OK in a normal domestic environment so long as small children arn't arround to push in the dust cap. If you are using it for PA work I would get a metal grill as its likely to get damaged when you are moving it arround.
Regards,
Andrew
Construction wise depends on how hard you are going to use it. If you use 18mm MDF and then use lap joints which are glued along the whole length you sould be ok. If you are still concerend and want to make it even stronger you could use a bead of wood appox 1cm square glued in the inside along the seams.
If you really plan to go mad with it and play loud bass heavy tarcks for long periods of time you could put a pressure release vent in the cabinet. Basically this is an intentional hole in the box usually about 5mm in diameter stuffed with felt to resist air flow. This will preven the presure inside the box from getting to high. However it will mess up the bass alignment to a certain extent so I wouldn't do it unless your prime use for the speaker is PA.
A ploy cone will be OK in a normal domestic environment so long as small children arn't arround to push in the dust cap. If you are using it for PA work I would get a metal grill as its likely to get damaged when you are moving it arround.
Regards,
Andrew
What type of lap joint should I use - Would a full lap joint be fine, or do I need to remove some wood from each for a semi overlap?
Semi lap would be better if possible depends on your wood working skills. Bracing will be required for sound quality as well as to prevent cabinet failure.
Regards,
Andrew
Regards,
Andrew
MDF does not glue well to the end grain.
A butt joint uses one side face and one end grain face.
This is not strong enough.
Add a batten along the inside of every corner.
Screw through the batten into the MDF and use PVA wood glue. This gives a robust air tight joint.
Plywood is better than MDF for rough handling.
A butt joint uses one side face and one end grain face.
This is not strong enough.
Add a batten along the inside of every corner.
Screw through the batten into the MDF and use PVA wood glue. This gives a robust air tight joint.
Plywood is better than MDF for rough handling.
I saw 1cm square wood battons in a DIY store earlier that are about £3 per 2.4 metres. Is this a large enough size, or would you suggest I use larger ones?
In terms of screws, is there a particular type/length that I should use and is it necessary to predrill all holes etc?
Also, I mentioned using a simple cross beam for bracing earlier - is this fine, or is there another design that would do the job better?
In terms of screws, is there a particular type/length that I should use and is it necessary to predrill all holes etc?
Also, I mentioned using a simple cross beam for bracing earlier - is this fine, or is there another design that would do the job better?
"If you want to improve the system further an inductor of arround 330uH (0.33mH) of a suitable current rating (you need at least a couple of amps) will tame what will probably be a very tissy mid to high range. It needs to go in series with the woofer."
Is there a particular type of capacitor that I should use? - there are many types on maplin.
Is there a particular type of capacitor that I should use? - there are many types on maplin.
In reference to the above post I meant inductor, not capacitor.
Anyways, onto capacitors - the 100v one which you linked won't explode will it?
Anyways, onto capacitors - the 100v one which you linked won't explode will it?
"The most inportant aspect of the capacitor is that it is high enough voltage - 100V for up to 100W and that it MUST be bipolar as it will be damaged and may even explode if you put a polarised capacitor in. Maplins range of non polar caps is below - they don't have a 4.7 but you could use a 3.3 and a 2.2 in parrallel which would be close enough and alow you some options if you want to try altering the crossover. i.e you could use just the 3.3 if you want more energy in the crossover region or even just the 2.2 if you want alot more energy in the crossover region."
Which arrangement would you personally go for?
Sorry for the multiple posting, it's just I keep of thinking of new things to ask. 🙁
Which arrangement would you personally go for?
Sorry for the multiple posting, it's just I keep of thinking of new things to ask. 🙁
Hi,
you could go as small as 15x15 for the corner battens, but 25mm square will do.
I would pre-drill both the battens and the MDF. The MDF bulges at the hole if the predrill is too small and the bulging cone forces the batten out of contact with the glue and gives a less strong and certainly not air tight joint. A 100L cabinet needs about 150 to 200 screws, 4mm (no8) by 40mm (1.5inch)
you could go as small as 15x15 for the corner battens, but 25mm square will do.
I would pre-drill both the battens and the MDF. The MDF bulges at the hole if the predrill is too small and the bulging cone forces the batten out of contact with the glue and gives a less strong and certainly not air tight joint. A 100L cabinet needs about 150 to 200 screws, 4mm (no8) by 40mm (1.5inch)
I can't seem to find exactly square batons to the dimensions you suggested, however, I have found 18x28mm - is that about right?
40 litres is the correct box size - do I need to consider how much volume the rear of the driver and magnet etc take up?
Should I predrill to exactly 4mm or slightly smaller?
Should I predrill to exactly 4mm or slightly smaller?
hi,
clearance the timber batten to 3.5 or 3.8 for 4mm/no8
pilot the MDF @ 3mm for 4mm/no8
yes,
add up all the lost volume items inside the box including the speaker, battens, bracing, vent and vent tube. Then make the box about 10% bigger than that gross total. You can add inert filling but you cannot add volume.
clearance the timber batten to 3.5 or 3.8 for 4mm/no8
pilot the MDF @ 3mm for 4mm/no8
yes,
add up all the lost volume items inside the box including the speaker, battens, bracing, vent and vent tube. Then make the box about 10% bigger than that gross total. You can add inert filling but you cannot add volume.
Hi,
in the days of only having a traditional screw with a plain parallel shank and the threaded end, we had to drill a clearance hole for the shank and in the other piece of wood a pilot hole for the thread.
Now that we tend to use screws which either have a reduced shank or thread almost reaching the head, the clearance hole does not need to match the non existent full size shank. A smaller clearance hole can be used for the screw to pass through, but I still recommend that the clearance be significantly bigger than the pilot.
The pilot diameter should roughly match the diameter of the core in the middle of the thread. It is there to allow the thread to cut it own path but leave room for the core, for two reasons.
Firstly to reduce friction and help drive the screw home with breaking either the screw or the slot and secondly, to reduce the amount of compression in the wood which is very relevant to hardwoods and also applies to MDF to prevent splitting.
It's primary purpose is not to guide the screw.
in the days of only having a traditional screw with a plain parallel shank and the threaded end, we had to drill a clearance hole for the shank and in the other piece of wood a pilot hole for the thread.
Now that we tend to use screws which either have a reduced shank or thread almost reaching the head, the clearance hole does not need to match the non existent full size shank. A smaller clearance hole can be used for the screw to pass through, but I still recommend that the clearance be significantly bigger than the pilot.
The pilot diameter should roughly match the diameter of the core in the middle of the thread. It is there to allow the thread to cut it own path but leave room for the core, for two reasons.
Firstly to reduce friction and help drive the screw home with breaking either the screw or the slot and secondly, to reduce the amount of compression in the wood which is very relevant to hardwoods and also applies to MDF to prevent splitting.
It's primary purpose is not to guide the screw.
Hi,
CPC will supply them WWW.CPC.CO.UK
If this link works it will take you to a suitable part it is 2.8A rated, they also have a 4.5A one if you want something better.
http://cpc.farnell.com/jsp/Componen...LOGIES/1433428/displayProduct.jsp?sku=PW00041
As for which option I would go with I would go for the 2.2uF + the 3.3uF as I don't like forward sounding speakers. Also this gives you the maximum options to play with if you don't like the sound.
Regards,
Andy
CPC will supply them WWW.CPC.CO.UK
If this link works it will take you to a suitable part it is 2.8A rated, they also have a 4.5A one if you want something better.
http://cpc.farnell.com/jsp/Componen...LOGIES/1433428/displayProduct.jsp?sku=PW00041
As for which option I would go with I would go for the 2.2uF + the 3.3uF as I don't like forward sounding speakers. Also this gives you the maximum options to play with if you don't like the sound.
Regards,
Andy
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