No, the only normal ‘danger’ is the person setting its controls. 😉
That said, SS amps in general tend to go nonlinear down low, so the greater a speaker’s efficiency, the lower its normal power requirements, ergo the more nonlinear the system response may become.
It’s a good plan then to pre-load it with some series resistance to ensure that it’s ‘demanding’ at least a watt or two at whatever the average SPL playback is.
This of course reduces the amp’s available power, so this needs to be factored in lest one may wind up clipping this seemingly too powerful an amp for the speaker’s rating on high amplitude transients. IOW, don’t reduce it below this rating and preferably 2x it or, its music [peak] power rating, whichever is higher.
Ideally this added resistance is factored into the speaker’s alignment, balancing amp pre-load requirements with any BSC ones to arrive at an acceptable tonal balance, system Qt.
GM
True, but the point I was trying to make is that at your average listening level your speaker may only be 'demanding' only a small fraction of a Watt or as little as ~0.016 W/channel with a 90 dB efficient speaker if listening at the ~75 dB typical TV volume.
GM
GM
Would putting a resistor around my 68uf cap (shunt?) be the same thing? I did this today with an 8ohm resistor and it seemed to kill the really annoying super hf noise while not killing the greatness of the hf? of course I could just be hearing things that aren't really happening (placebo effect)
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Wow, this is an old thread I started a couple years ago. I never did follow up with my results. Unfortunately the original design has been dismantled and changed but it did get built per spec and it sounded decent. I never got around to packing them up for the 60 mile trip to Danny's to measure them (GR-audio) but I would say they were better than expected but probably not as good as reviewed. Years of dove hunting and working with power tools have damaged my ears to the point these full range drivers used for the too end fell flat to my tastes. I ended up experimenting with several other drivers in the top end and came to like the Alpair 8" driver using a Beorhinger EQ and bi-amp system with a 300B SET for the top end and a class D for the bottom. It was a fun project but I don't think I would pay retail for the components required to build them. If anyone does want to try them I have the drivers and possibly still some of the EQ components. All lightly used and in perfect condition. Shoot me a PM if you are interested and I will gladly sell them for far less than retail.
Thanks!
Thanks!
It should be noted that there has never been an 8" Alpair. You mean the 6.5" Alpair 12 /12p?
dave
Hi there, did you built this kit with visaton b 200 or something else ? I really want to know about this driver's high frequency performance..
Stock the HF is a laser pointer with a tiny hot sweet spot. When we 1st had B200 1st thing we started thinking about was an added tweeter. But 1st thing we did was add phase plugs which do a good job of dispersing the top end, inmproving sweet spot size and giving the driver more balance.
It should also be noted that the measured sensitivity of the last batch i had is near 92.5 not the 96 specified.
dave
No, the one that exists in my head as I was drifting to sleep when I wrote that...yes, I'm an idiot, the Alpair 6.5" AKA 12. Although I have always thought they should come out with one if it were technically possible. The transducer material is exceedingly thin and would likely have a difficult time with that large of surface and associated forces. It's been a year and a half since I paid attention to the model but something tells me it was the 12 and not the 12p that I own.
One of my all time favorite drivers BTW. The Aplair 8", but really only 6.5" 12, that is.....
No, no placebo effect. If the driver is nominally 8 ohms, then an 8 ohm resistor in series ~doubles Qts.
GM
Did you ever tried with a tweeter,and how was your method? Actually i am not experienced at crossover issues..
Never tried to add a tweeter to mine either. Felt like it would defeat the purpose really, might as well build a well documented two or three way design with less expensive components. I got into the full range thing late. Having already spent long hours trying to build and design a multiple driver system the full rangers really appealed to me. Seemed like going backwards.
Dave, didn't you have some measurements you made with and without phase plugs on these B200's?
Dave, didn't you have some measurements you made with and without phase plugs on these B200's?
I built it as specified first and didn't really like the HF performance of the B200 so I swapped out the B200 with a few other full range drivers I had on hand that were a similar size. I built it with some heavy cunstruction grade plywood just to see how it would sound. Later I just cut out a square section around the B200 and made a few different baffles for each driver and swapped them out. I had to play with the XO obviously due to the varying impedence of the different drivers and this was cumbersome. Although I got a few iterations to sound good it became much easier to bi-amp with a good electronic XO. Eventually the only thing left with my version of this design was the LF driver and baffle.
Like I have mentioned before, I have significant HF hearing loss from years of shooting guns and working with power tools and on large construction equipment. I'm sure these B200's sound better to others than they do to my poor old ears. Which brings me to a point I must make.....please wear your hearing protection when you are working with loud tools, guns, etc....you will regret it someday if you don't. It's kinda like smoking., it sneaks up on you slowly then one day you wish you had quit years before.
I am firstly planning to upgrade nobox kit cables with dh labs t-14 . And later i will upgrade the capacitors and resistors.How about the quality of this kit's crossover ?
I didn't buy the kit, I came upon these drivers separately and picked them up secondhand. The 15" were new and the B200's were slightly used. The schematic was given on The review site and the dimensions of the cabinet were freely available as well. I just cobbled together my own XO using some oil filled can type poly caps I had laying around (like Klipsch uses in their XO's) and unwound some inductors I had to match what was needed. The big ones in series used in the low pass network required that I buy the larger of the two. I think I used a steel laminate from PE but don't remember for sure. I don't know what the kit sells for but if you haven't bought it yet you might consider just building your own XO's if it's cheaper to. They are simple and the 47uF oiled can poly can be had for less than $6-7 in many surplus outlets. Then you can easily tweak things if needed, much easier than when they are glued to a board. I also wondered if it would sound better to use a single large inductor for the 13nH instead of two in series. FWICR there is some issues you can have with series inductors that make then inferior to a single inductor of the same value. Whether or not those issues come into play on this particular network in an audible way I don't know. Maybe someone here could expound on the use of series inductors. It's been a while since I've thought about this stuff and cannot remember what they were. Maybe some resonances between the two or something similar.
Another thing was the shaping network for the HF on this XO. I tried it without the BSC and tweaked it around some and in the end I think I had the best sound using a simple 2R-3R resistor in place of the 1.5mh and 10R in parallel or even just using nothing there. Again, it's been a while but I do remember playing with this part of the network yielded the most impressionable changes.
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Thank you very much for your informations Sir,I've ordered the kit from germany and i am waiting for it..I read too many positive things about b 200.
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