My IPL Build

[The Alchemist]

I've finally had time to post a few pictures of an IPL build. I always like to start by building the crossovers.



http://i1381.photobucket.com/albums/ah213/thealchemist3/DSC_0411_zpsroxtt9ob.jpg (http://s1381.photobucket.com/user/thealchemist3/media/DSC_0411_zpsroxtt9ob.jpg.html)



One handed cramps are ideal.



http://i1381.photobucket.com/albums/ah213/thealchemist3/DSC_0435_zpsrqzr02o7.jpg (http://s1381.photobucket.com/user/thealchemist3/media/DSC_0435_zpsrqzr02o7.jpg.html)



I never usually put in any cabinet braces as suggested and I have never had any problems but since the Kevlar coned bass units produce a large amount of bass I thought that I had better use something to prevent unwanted resonance. I decided to use 8mm screws of various lengths.



http://i1381.photobucket.com/albums/ah213/thealchemist3/DSC_0436_zpsko2keaoq.jpg (http://s1381.photobucket.com/user/thealchemist3/media/DSC_0436_zpsko2keaoq.jpg.html)



Note the alignment board at the back of the cabinet. The glue that I use allows no movement after the two surfaces touch so accurate positioning is essential.



http://i1381.photobucket.com/albums/ah213/thealchemist3/DSC_0420_zpsy8os02bv.jpg (http://s1381.photobucket.com/user/thealchemist3/media/DSC_0420_zpsy8os02bv.jpg.html)



These are a pair of speakers that I made earlier........The uneveness in the grain pattern is a photographic artefact, honest!!


http://i1381.photobucket.com/albums/ah213/thealchemist3/DSC_0428_zpsz7fvabx5.jpg (http://s1381.photobucket.com/user/thealchemist3/media/DSC_0428_zpsz7fvabx5.jpg.html)


Hope the above is of some interest to would be speaker builders.

[awkwardbydesign]

Very nice. I have a fondness for TLs, but they still need tweaking for best performance, IME.

[karma67]

What wire did you use for internals? hu1?

[The Alchemist]

Jamie, you are correct. The internal wire is HU1. Richard rightly observes that a bit of fine tuning is required but this is easily done. Ivan has changed his crossover design recently and has one resistor that can be changed to give a bit more or a bit less treble. The bass can be tweaked by varying the amount and position of the long haired wool. For example, in my S2tlP's I have some well teased out wool behind the driver but in the tlK's I have used 10 grams behind and 6 grams at the start of the line which is supported by some nylon mesh tucked in underneath the profiled acoustic foam on the baffle underneath the bass unit. Unfortunately I put it in place after the picture was taken so it does not appear in the photograph.

[Covenant]

A beautiful job all round.
I have used pure silver speaker cable internally. What do you use to support the foam over the bottom bass port?
I am undecided about the fixing for the grille. I want to use magnetic fixings but they may be a bit close to the drivers,

[awkwardbydesign]

A beautiful job all round.
I have used pure silver speaker cable internally. What do you use to support the foam over the bottom bass port?
I am undecided about the fixing for the grille. I want to use magnetic fixings but they may be a bit close to the drivers,

The speakers have big magnets in them, so probably won't be worried. I found that putting the magnets under the veneer caused grey marks to appear as iron dust stuck to them. I would fix steel washers to the cabinets another time, and put the magnets the grills. My current speakers don't have conventional grills.

[The Alchemist]

Hi Jerry,
It's not very clear from the photograph but I do not use foam at the mouth of line. To be honest I find the foam that Ivan supplies rather ugly so I prefer to make a grille frame out of 10mm X 15mm aluminium angle (Wickes) and cover it with grille cloth. This is, I admit, a real fiddle but I think that it is worth it. I start making the frame when the cabinet is complete, i.e before veneering. Lengths of the angle are cut to size and mitred to make an oblong supporting frame which fits snuggly in the aperture. I have done the cutting by hand but it is much easier using a mitre saw (I use an Evolution Rage which has a blade which will cut metal). When all four pieces are cut I put them in the aperture (a bit if "fettling" is required!) and glue the corners together with Araldite epoxy. Line the corners with greaseproof paper or you might never get them out again in one piece! When the glue is set the frames can then be carefully removed. The corners are rounded very slightly with a file so they do not puncture the grillecloth. The frame could be painted matt black but I prefer to cover them with black dci fix (Wilkinson). This "pads" the frame a little and protects the corners. The tricky bit is to attach the grillecloth to the frame so that it is nice and taut. I use spring paper clips to tension the cloth before attaching the cloth with hot melt glue. I admit that this is a very tricky process and a bit of practice is required. It is difficult to get neat corners but it can be done with care and a bit of crafty scissor work. There is little space to attach the cloth and the glue must be used sparingly or the completed frame will not sit flush in position. The excess cloth / glue is then removed with a scalpel. I use the same black dci fix to cover the back of the grille frame. I think that Ivan recommends hot melt to fix the grille cloth on but I always use small staples since they are easily removed and repositioned if the cloth does not sit nicely. I believe that conventional wisdom in attaching the cloth is to work from the middle out. When doing it that way I have never got the corners to sit neatly so now I start at the corners, then the middle and then out to the corners, always stetching the cloth tightly before firing the staple. Works for me! I have never used magnetic grille fixings but I am very interested in using them on my next project. Any advice from more experienced members would be very welcome.

[Reffc]

Nice job Richard.

I no longer use staples for the frames as hot melt is all it takes, allowing an inch or so of material round the edge (excess can be trimmed with a scalpel) glued into a rebate (formed with a router or bull nosed plane). Corners are tricky but there's a few methods, the easiest I find is trimming the corner pieces to an angle to reduce the amount of fold in required for a neat job. Another tip is to glue some nylon/polyester ribbon over the joint to neated everything up and provide a nice smooth finish for placing up against your speaker baffle.

RE magnets, they are a very neat solution but there are a few hints and tips. The first is to work out the specific size and type required based on the weight and size of grille frame. I normally use 3mm thick 10 dia N42 neodymium magnets, exact number per face determined by sliding force (back of fag packet calcs based on weight of grille which you ensure that you double or treble up on...ie force = 1Kg, = 250g per magnet joint per 4 nr per face, so look for magnets which have a sliding resistance of at least 500g to 1Kg). You ignore the fact that two are used per join as the gap introduced by veneer or covering weakens the published magnet force. They will not move downwards providing the correct strength and number are used er frame.

The other important thing of note is that the magnets themselves are not especially durable and not suitable for raw, magnet to magnet fixings without surface protection as the plated coating is easily damaged. I would recommend a 0.5mm to 1mm skim of epoxy over the magnet surface even if intending to veneer as the surface sanding for veneer prep will also damage the magnet otherwise.

I have no problem with discolouration when using two magnets (which you have to if wanting to hide them avoiding unsightly washers or steel strips etc marking the front). The secret is in the finish applied. Some finishes will be prone to discolouration through the attraction of fine iron dust and other magnetic dust particles forming with age into the finish. Wax and some oil finishes tend to be most prone, but if you use a PU finish such as General Finishes Topcoat, any dust forming can be simply wiped off without risk of discolouration. This finish is also available in satin/sheen. It's possibly the toughest finish you can apply (suitable for flooring for example)

[awkwardbydesign]

I have some 9mm (?) black grill foam, thanks to oceanobsession. and stuck 2 layers together with dabs of this - http://cdn2.bigcommerce.com/server4900/180d4/products/1620/images/2272/AdUHU-Por__13365.1409550138.1280.1280.jpg?c=2
and it wedges nicely in the port.
If you use magnets, try to ensure there is a lip, or similar, to take some of the weight of the grills, or they may gradually move downwards!
These do. ATC SCM11.
http://www.atcloudspeakers.co.uk/wp-content/uploads/2013/05/ATC-11-speaker_grill-on-e1375348761251.jpg

[Covenant]

Hmmm- with regard to the magnet grille fixing, I was planning to countersink steel screws level with the face and run the veneer over them. Being screws, it would mean you could get them flush easily. The IPL grilles are lightweight-194 grams, adding for cloth say 200 grams.

[awkwardbydesign]

I used 12mm dia magnets and similar sized washers. A flat bit made shallow holes and I epoxied them in. The wider the magnet and washer, the better the grip without going for stupidly strong magnets. If you need lots of grip you can use a second magnet instead of a washer, or stack the magnets to increase the magnetic field.