Discussion in 'DIY' started by SirReal63, Jul 5, 2018.
I'm stunned by the beautiful look of that veneer! Wow!
My phone camera does not do it justice.
A couple more shots of the veneer, this was after the second coat, the flash really shows contrast between light and dark that the eye does not. My phone still does not do it justice, it almost glows.
The seams and grain continuity really turned out better than I hoped. This was my first "real" veneer project.
Your enclosures look simply stunning with that Teak veneer. Your supplier did a good selection for you, and your work applying it is spot on. I'm loving this process. Thanks for keeping us in the loop on your project.
I have a couple of questions on the passive crossovers you are employing until you go to your biamp setup. I'm confused about your description of running the tweeters and mids in parallel to yield a 4 ohm combined impedance. I'm not a whiz kid when it comes to crossovers or electronics in general, but in a traditional crossover configuration the impedance "seen" by the amplifiers is reflective of the drivers individually, not combined. For example, a three-way network with three 8 ohm drivers "in parallel" will present an 8 ohm impedance to the amplifier. Am I missing something?
Second question is in regards to your choice of low/mid crossover points - 100Hz for the mid, and 500Hz for the woofer. I'm sure you know that convention has always been common crossover points, ie, 500Hz for the mid and 500Hz for the woofer, otherwise both the mid and the woofer will be reproducing the same frequencies between 100 and 500Hz, which will result in a 3-6dB accentuation of those frequencies.
Please pardon me if I've completely misinterpreted your plans. I'm a relative amatuer at crossover design and thus relegated to regurgitating what I've read by the real experts. So my inquiry is purely elemental and generated by an understanding that is just deep enough to be dangerous.
I will never claim to have everything figured out, but I have researched this to death and have a game plan. That game plan will work until I get hit in the face, then I will adapt.
The reasoning behind separating the low from the mid and highs, each with 4 ohm loads is so that the speakers can either be run off a single 8 ohm amp or split into two 4 ohm loads for two amps is so that down the road whomever ends up with these speakers has the option to run it with a single amp or multiple amps. Two 8 ohm speakers in parallel will present 4 ohms to the amp. The 4 ohm low and 4 ohm mid/high in series will present 8 ohms to the amp, thus enabling a conventional 8 ohm amp to play the speaker without fear of damage to the amp. I have to change the binding posts so that when the bridges are in place it runs the speakers in series instead of parallel.
Three 8 ohm speakers in parallel will present 2.7 ohms to the amp, dangerous to most amps.
I chose the crossover points based on the frequency chart of each speaker (with exception to the sub, none was found, hence the need to experiment a little) to take advantage of the optimum frequencies of each driver. For the 6" mid it has a relatively flat response from 100 hz to 3500 hz, there is a large peak at about 3500 hz and I will roll it off at 3500 hz to avoid that peak, this should work well because the tweeter begins at 3500hz. I fully expect to have to play with the crossover points but this should be a good starting point. I expect to have to lower the crossover point for the sub, I suspect it will be too muddy above 100 hz, but I won't know that until I burn in the sub and see how it actually performs, it has a frequency response of 29-800 hz, but without seeing an actual frequency response, I do not know how it performs. It is entirely possible I will need to raise the low point of the mid driver, if the sub performs better than I expect. The beautiful thing is the crossovers are cheap which lends beautifully to experimentation. If I have it correct right off the bat I will be slightly disappointed, the fun here is in the learning and tinkering.
For me, the crossovers will be temporary, I plan on an active crossover, but I want to leave the passive ones in the box for the future.
Another source that helped greatly with the box design...
Trying to figure out the cubic feet of the box was a challenge to my old brain, the calculators here made it a snap and allowed me to design the box based on the needs of the woofer as well as tell me the optimum size of the box for the mid.
Oh, and I am not even an amateur at crossover design, this is my first attempt, it will work or it will fail.
Thanks for replying. I understand your thinking on the crossover points you've chosen. It will be interesting to see how they work out (and, as you say, fun and educational - let's not overlook the point of a personal build.).
Anyway, continuing to watch and enjoy. Can't wait to see your further progress.
If I had no concern about anyone else, I would just do an active crossover from the start. These speakers will outlive me, I have already died once and I know I will again. I need to do the right thing and make them idiot proof for the future, our idiots will inherit them.
It keeps me busy and out of the heat, I cannot take the heat any longer. I would be finished with them if I could stand to be in the shop for more than an hour at a time.
The speakers are almost finished, the Left is assembled, crossed over and breaking in. I will definitely have to change the sub crossover down to 100 hz, it is muddy and did not drop enough in the upper frequencies to blend in with the mid. It is ordered and will be here today. I am glad I chose to L-Pad the mid and High, their higher sensitivity overpowers the bass, so they are padded down.
The sound is actually better than I hoped, the mids and highs are very clear and detailed, the bass may actually be hitting 30hz which I had doubts about while building. The bass hits with enough authority to be felt 30' away. All in all, I am very happy with the sound and it should improve with the crossover change for the sub. I had it playing off my old JVC RX-709V for a couple of days to break in the sub, yesterday I moved it upstairs to it's final place and hooked it up to the Sonance amps, it should be more than I ever need for sound.
Great looking build. And, if I may brag a bit, I did say they would sound great in my first post.
I was wondering when we would hear from you again. The speakers look great. Thanks for the update. Keep us informed as you dial in the crossover frequencies.
Sure would be nice to have an active crossover to use to immediately dial in the correct xover frequencies, then all you'd need to do is build the appropriate passive to match those on the active.
Yes it would, but there are budget constraints, the house build comes first and doors are next on the list. SWMBO wants nice doors, amd there are a lot of them.
I want a really nu e active crossover, and they are not cheap. I am leaning away from the miniDSP.
You know, it just dawned on me that you could rent an active xover and any other gear you need from a music store or prosound rental. You'd need the gear for only a day or two, so the cost would be piddling. The active xover would allow you to dial in the exact xover points you want, then you'd know which passive to build.
Hmm. I might do just that to fine tune my Altecs.
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