Build log: DIY rotary sub for contemporary HT in 100 year old house? - Page 4

Thanks for all the ideas. Yeah, the old wiring has a couple breakers going into one box and then about 6 lines going out of the box. Who knows if they are joined to other circuits somewhere else in the house. I will be turning off the main breaker for those and removing everything from the box to the breaker. Then I will be putting in new stuff to the box. I can do everything stepwise one breaker at a time, but with the main off. I'll use a battery powered headlamp during the day when I have the main off.

I have about 6 hanging lamps on old wiring that are joined in with other whole house circuits. I want to remove the lamps so I can just go directly from the panel to the house circuits. When I remove the lamps I will be using old plug in lamps as you suggest. Maybe I can cruise the neighborhood on Thursday evening to see if anyone is throwing them out. If not, I'm sure Harbor Freight has some cheap shop lights.

Here's another pic of the wife's attic space. I don't want the thread to just be text.

We have joked about not seeing each other after the HT is done. I do like my wife, so I'm not trying to get away from her (most times). I was thinking either some kind of intercom or even Yahoo Messenger would be a good way to communicate over 3/4 floors. I have my cell phone on me pretty much all the time, but she never knows where hers is, so that may not work.

I don't sell slope planes anymore. I decided I wanted to work on the house instead. I think that was an excellent decision. ...and yes, they are frustrating, especially at first. Now I am a computer programmer, but I used to be a pharmacist too.

Like I said, my wife is pretty awesome. Here's a pic of her in front of our artcar. Don't you agree?

Yes, that was the special Vehigloo option for Corollas offered only 1991. We are giving it to someone else in the next few days, actually. It is very fun to drive around in.

My wife could always come down to the basement to talk to me, but I can imagine that what she wants to tell me is something like: "bring me up a drink and a snack." I bet she will just wait until I'm done and I come up to the second floor before she tells me that. Then I can go down again, then up. Oh man, that will be so much fun! Ha ha ha!

So, I spent just about $666 on plumbing for the heating system. That was more than I thought, but the dielectric couplers to convert from threaded galvanized pipe to copper were $35/50 each and I needed 4/2 of them. Actually, they only charged me for 2/2 of them for some reason! $250 of 1.25" copper pipe also. It is much cheaper than having someone else do it and I gain a bunch of height, so it is worth it.

The dielectric couplers are so that the zinc in the galvanized pipe and the copper don't contact each other (rubber gasket) to form a battery and oxidize very quickly.

My phone needs to be replaced and I have a couple of honey-dos for today so I'll see how much else I get done.

Ok, I think I got a bunch done. I did some soldering of 1.25" copper fittings to the dielectric unions for the heating system. I then wrenched the unions onto the galvanized pipe. I am now ready to solder on all the copper. I probably would have finished that except I kept debating (in my head) exactly how to do it.

So I decided I would prep for a new beam going in. There is a lot of electrical (and plumbing) hanging on the existing beam and next to it. I removed/replaced maybe 8 circuit of old BX wiring. It has the metal casing and the cloth/wax wiring inside for those that have no experience with it. The ground is through the casing.

I have a whole pile of the BX cabling now. I also have new dedicated circuits for the window AC units on the first floor.

I have a light switch at the top of the basement stairs that I'll be converting to a 3 way switch so I can switch on/off from outside the HT. It will control the stairs lighting and the small HT anteroom/lobby lighting. I'll need to pull some 3 conductor wire for that.

My wife has a friend staying over this weekend from out of town. That should occupy her enough so that I can work in the basement. I'll keep chugging along....

I didn't get much more done. I made a couple more circuits and did some "recon" behind the kitchen appliances. I think I will get more done long term if I give myself some time to recharge. It's only been a month since I started my project. I'm on a good pace so far.

I demoed the THT to my wife's friend. She just sat there in amazement. Half way through the WotW's pod emerging scene, I paused it. She said she felt like she was having a panic attack. I felt it too. Those LFEs really do a number on your body!

I built a THT. You can look for reviews/build threads on the DIY speaker forum. Plans bought here: http://billfitzmaurice.net/THT.html

Bottom line on the THT: $155 for driver, $70 for wood + $150? for 200 watt amp will get you an enormous amount of low bass (15 hz and above). It is also large at 3 x 3 x 2 FEET. I have never heard anything like it, but I am not an audio expert, etc. I know it is about 50 times more impressive than any regular movie theater I have gone to. There are more impressive systems, for sure, but for $225 (I already had an amp), I don't need any more bass. I would never be able to stand it fully on for a whole movie.

I used the recommended DVC driver. There is really only one that will work with it and it is in the plans. It is a no-brainer. I am using a Crown XTI 1000 amp, but it is way overkill. A bunch of people are using 200 watt "BASH" amps. You won't believe what kind of sound you can get with 28V. Oh, and it is super clean. The folded horns have great SQ.

Here's a pic of it partially done. Note the coffee cup for size!



I haven't done any SPL measurements, but am going to at least run REW on it someday after I get a receiver. All I know is it gets uncomfortably loud. I can rattle windows and lights on the floor below. It is extremely impressive for the cost. Try one and if it is not enough, build another one! The thing is that those who have two admit they barely push them because they are too much.

If you are even considering it, stop wasting time and just make one. I highly recommend it. You could easily sell it for cost of your parts after a demo. It took me a total of 6-8 hours to build over a few days, but I'm a quick builder.

Let me know if you have any questions about it.

Matthew: I would say you couldn't use the driver in the THT, but Bill would answer you over in the BFM forum on his website. You might be better off making your THT and selling your current sub. Doing an 15" wide THT as opposed to a 24" will save you a fair amount of space and some wood costs. It will not save you much if any time though. After 8+ hours of work you may appreciate 50% better performance as opposed to saving a few bucks. I would recommend 24" wide unless you cannot fit that size in your space.

Basically, the horns are very specific on what drivers they use. If Bill knew of a cheaper, better alternative he would have used it. He researches the drivers quite a bit. $155 for a sub driver is actually quite cheap and the 15" is pretty damn big and beefy.

Also, definitely get a decent plywood (specific kinds recommended in the plans). The biggest cost for the THT is labor, so do get the right materials.

Phillip: Thanks! I can't wait either. I just have to keep working on it and before I know it, it will be done. The THT does take up a lot of room, I agree. He has another option with the Table Tuba. It is a bit smaller and cheaper, but only goes down to 30 hz or so. It puts out way more output than your satellites too!

I made the TLAHs (plans also on his site) for mains that keep up with the THT quite well. I only have $25 into each speaker. I have a build thread if you search for it.

That is a good plan. With the specs he can tell you whether it will work or not. I'm sure it is a good driver. It's just that a good driver for a direct radiating design is not the same as a good driver for a horn. Different drivers for different jobs!

You might also consider building the 24" wide and then making a mounting plate so you can use the 12" driver on the 15" baffle. It really depends on the specs though....

Sell the Adire first? The guys on the BFM forum might be able to tell you how they compare. I don't know. You (or anyone) would be welcome to come hear mine.

Thanks Phillip! The plans are cheap, but still not free. They are a good deal and you will end up with something that sounds really nice and has great output. He is musician also so he tends to go towards "pro" gear -- for bands/clubs, etc. So, the output is usually quite good on his cabs. They are also geared towards value with very good performance per $. If you want the ultimate SQ, you can go another route, but it will cost you several times the price. It all depends on what you want!

My thread is here for those interested.

My mains: They aren't clamped anymore!

The bass also has an intentionally twisted neck! It makes it a bit easier to fret octaves low on the neck. I made the neck on the CNC, and the rest of it with hand tools. I want to make another one, but haven't really played for a while. I learned/took lessons a few years back for bass, then guitar. I played quite a bit for a couple of years.

The biggest advantage (I think) for the line array style is that you can get a lot of volume for a low price. Each of the woofers were $1.25 and the tweeters were $2. When the drivers are stacked, instead of a half sphere of sound radiating towards you, the spheres get squashed vertically. So instead of the sound spreading out vertically and horizontally like a single driver, the sound spreads out horizontally, but comes out vertically closer to a line. So you get 3db more sensitivity/volume over a single driver each time you double the number of drivers. So, even though one of each driver would not come even close to putting out enough output, 8 drivers will give the equivalent of 8x2^3 or 64 drivers. Is that right? 1 to 2 to 4 to 8 = 3 x 3db = 9 db. 10^(9/10) = 8. 8 x 8 =64. Wow, even I didn't realize that.

If you are far away from the line array for its height, the line array is even better since sound isn't wasted up into the sky and ground. For rooms that don't have ceiling or floor treatment (absorption), it can be a benefit too. My short ceiling height room is a good example.

The disadvantage is comb filtering, which comes into effect if the spacing between the drivers is large relative to the wavelength they are producing. This is because the sound is being generated by two or more different drivers and arriving at your ear at two slightly different times. This causes comb filtering which you can probably research on wikipedia, but I recommend the book, Master Handbook of Acoustics! It discusses that topic and others really well.

Great news on the THT. Looks like you will be able to use your plate amp too, which is a bonus. Are you going to do a build thread? It will be interested to hear what you say about the comparison between what you have now and the THT.

Oh, and as far as the comb filtering goes.... If my TLAHs do it, I don't notice! They sound great. They are amazing bang for the buck. Again, there are better speakers out there, I'm know....but not for <$25 a pop!

Finding room for it is certainly an issue. It is not a small enclosure. The mouth needs to be 18" from the corner of the room, which makes placement even more difficult. A coffee table is near the center of a room. An end table would make more sense. The problem is that what ever you put on top of it will vibrate. I don't think it is the enclosure as much as just a lot of low frequency output. The enclosure is really rigid and beefy. I'm not sure I would want a lamp or a drink on top of it while it is cranked though.

If it is anything like the 15", I think you will be impressed. I like to recommend the 15" since I *know* it is awesome. I have no experience with the 12".

I have a friend that is a bit of an audiophile. He thought that the TLAHs couldn't sound good for that cost. He was very surprised. He said he would build them if he didn't already have great speakers. Now, if you have only 1 of these cheap drivers, it would be overdriven and distorted to get any reasonable volume. With "64" of them, it is a different story!

8 x $1.25 drivers = $10
6 x $2 tweeters = $12
1 x $1.25 resistor = $1.25
wood $8
Oops, $31.25 plus PL glue. Ok, I don't know where I got the $25 figure.

The piezos/tweeters output drop below 2khz. I tried it with a LP on the woofer and a HP on the tweeter and it didn't sound significantly different to me after I EQed them. I have to EQ them anyway because the piezos frequency response isn't flat. I figured why not EQ out at the crossover frequency range too? I'm sure it is not "ideal", but I really couldn't hear a difference. So, I decided to save a few bucks. It would be very easy to add the crossovers later anyway.

When I get my new space, I'll have more of a chance to mess with REW and such. I bet sound absorption in the new space will make a bigger difference anyhow. Perhaps then other problems will be more apparent to me?

Last week I broke my phone and needed another one. I was a bit preoccupied with my shiny new fancy phone. I bought one for my wife too, but hers wasn't working well and that also took up a bit of my time.

I did get to work down in the basement. I basically did just more electrical work. I needed to pull all the wires off the beam I am replacing. I did that, but need to drill holes in the joists so that I don't use up any ceiling height. I also need to do that for water supply and a drain pipe for the kitchen sink. I needed a 90 degree drill and found one to borrow for a bit. I didn't need it for the electrical wires (that bend), but for plumbing, it is needed.

I made a couple more circuits, incorporated a few more and replaced a bunch. I've done a bunch of electrical work in 2 weeks. I can only imagine how many thousands of dollars I've saved already. 3 weeks to replace and move every bit of electrical in the basement of an existing house doesn't sound too slow, does it?

I figured I was making good progress even though I know I could be doing better. Heck, you probably could even get an electrician to show up within two weeks, right?

The LP-THT should let you change out to the spec'ed driver a little easier than the original THT too. One will probably be enough, but if you want to make people physically ill go for two! I feel a little ill after having mine cranked with the real low stuff....