Perhaps not... I've seen Longwave UV (that's the kind that comes in thru even North facing windows) fade paper cones and rot the Crap Foam some makes use(d?) as surrounds... even when behind grills... which offer little real protection. Pervasive radiation indeed.
Albeit it does take years, it's nonetheless genuinely destructive of insubstantial materials
I wouldn't know. I'm a neophyte. Maybe you could quantify what overkill represents here. I was just applying the philosophy: use as little as possible but use the best if possible. I know I have fallen short on both counts, but I have made a start, and the result sounds pretty good considering what I have into the system (the speakers keep sounding better and better and I haven't yet done all that it is possible to do to improve the sound).
Speaking of improvement: I ran across a great suggestion (because it worked) on a builders web site. He had grounded the basket of the driver to the negative terminal on the driver. Bit of hassle and almost no cost for a tangible improvement to the sound. I was thrilled.
The baffle step circuit was some what more expensive--about the cost of one driver. On the other hand, instead of buying the kit from Madisound I could have built the enclosures from scratch and saved about $70.00. The kit saved me many hours. And simple as it was, the baffle step circuit assembly took quite a few hours to assemble. I don't have to value my labor in dollars to still want to make my labor pay.
Roger
I've had foam surrounds rot, drivers never used stored in their original boxes in a dark space. No UV required.
dave
Making the horn mouth in the back completely changes the speaker, both the sound and layout as driver chamber needs to be positioned to allow driver access to back wall which now becomes baffle. You might look at DNA or Busch horn designs. Although it would be interesting to see a sim of the BK12 with a rear firing horn. I might give it a go in Akabak.... it is no longer a BK12.
Sim of rear facing horn
If you could rearrange the mouth to be rear firing, here is how it may look as an Akabak simulation. The bass level is reduced a bit but appears to be flatter. There may be some benefit to a rear facing horn. The first plot is the BK12M as front horn, then rear horn, displacement, and impedance plots. This is with the speaker located 72 in away from a back wall, 1 watt input with sound pressure at 1 m away from driver centerline. The driver cone displacement is rather high (1.2 mm at 1 watt) given that xmax for FE126EN is only 0.3 mm.
If you could rearrange the mouth to be rear firing, here is how it may look as an Akabak simulation. The bass level is reduced a bit but appears to be flatter. There may be some benefit to a rear facing horn. The first plot is the BK12M as front horn, then rear horn, displacement, and impedance plots. This is with the speaker located 72 in away from a back wall, 1 watt input with sound pressure at 1 m away from driver centerline. The driver cone displacement is rather high (1.2 mm at 1 watt) given that xmax for FE126EN is only 0.3 mm.
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The FH3 is a tapped hypex rear horn with no driver chamber - a very different design and will sound different than flipping mouth of BK12 to the back. Interestingly, I put a FF105WK into the sim and reduced driver chamber vol to 1.2 liters and it works pretty well. It has more xmax so won't be running into the excursion limit as easily as FE126EN and it's bass will be more balanced with its lower SPL for higher frequencies.
I am breaking in a pair of Alpair 7 drivers in my BK12 enclosures...much to my surprise it sounds great. I removed the back magnets and use a baffle to flush them out. Great soundstage and good bass.
IMO much better performance all around compared to the 126 they are designed for. These will find there home in an FH3 [eventually] but I am considering using these as rear speakers once that happens and getting Alpair 7s for them.
But I am new at this so I am sure I am braking some sort of rule
IMO much better performance all around compared to the 126 they are designed for. These will find there home in an FH3 [eventually] but I am considering using these as rear speakers once that happens and getting Alpair 7s for them.
But I am new at this so I am sure I am braking some sort of rule
Not really. I designed the BK12m to meet a particular set of requirements -it is the way it is because it needed to be. Since in design terms it's a scoop bin derivative with a moderate swept volume, you will likely discover that a few other units work in it -the FF125wk for instance, especially if a voltage-source amplifier is involved. I haven't bothered looking though because I haven't had any call to do so. For what it is, it works well, & is both simpler, and a better performer than the original BK12.
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