Bathroom mini-update 4

Not much more to share yet, but here’s a shot of what the shower looks like today.

I think it’s going to be pretty stylish! I’ve said it before and I’ll say it again, Kaitlyn has a good eye. 

We’ve been told that the end of this is going to go pretty quickly, possibly finishing on Friday. That’s super exciting! It will let us get started on the floors earlier than we though, and might let us get into the house as early as the first week of October, including a week for floor refinishing and a week for fumigation. 

I have to admit that I’m just a little nervous at this stage in the bathroom remodel. I’ve never done this before so I don’t have a great sense of how much work has been done compared to how much is left, but we have paid the vast majority of the contract payment as of our passed inspections, so I’m really trusting their good word that they will finish the job well and on time. I’ll have to talk to some people about how best to structure the kitchen contract (a year or more down the road) to limit my anxiety on that. If these folks do well then they might get hired for that too, so I’m not super worried that they won’t deliver. 

They seem to be doing a great job. I came in, and they had some cloth down to protect the floors as they walked in and out from the bathroom, and they are leaving things clean and orderly each night. 

It’s probably standard practice, but I appreciate seeing it and knowing they’re taking steps to get things right all around. 

Bathroom update 3

It doesn’t look like much, but apparently we have passed city inspection for electrical and plumbing in the bathroom.


You’ll notice a few things in this picture; first we have two shower heads and two valves. The lower valve is the main water control, and the upper switches between the two shower heads. The pipe to the lower right is for a hand shower, and the higher one will be a big stationary head. 

It was harder than we thought to find fittings that matched and allowed the hand shower, but Kohler had a good collection that let us get it done for a fairly reasonable cost, and hopefully the long term quality and temperature regulation are good enough that we avoid buyers regret.

Some of the other options we found when we were shopping had flow rates as high as ten gallons per minute, but both of these are California-legal 2gpm. That’s important for conservation, but also so that it doesn’t tax the tankless heater that we’re planning to install to replace the old one that’s past it’s life span and is a bit leaky. 

We hear that the bathroom may actually be finished within a week! As slow as everything else is going that almost doesn’t seem real, but I guess that’s what you get when you hire professionals. 

Bonus picture of Penny. 

Bedroom update 2

This morning I had to take care of something for work, and Kaitlyn headed over to the house before me and got the baseboards coated in Citristrip. By the time I got there they were ready to go, and we spent a while scraping the paint.

This part is gross, but… I got really pruney inside my rubber gloves. Not fun!


It also became clear that we need to think more seriously about popping these off and really finishing them well outside. It just isn’t that easy to get the edge that’s close to the floor. I read an internet tutorial, and it worked out pretty well. Fist you insert a couple of flat blades in between the wall and the molding:


You have to use really thin blades to get in there, and I already found out how easy it is to bend a corner. I might have to grind that off…

Anyway, the next step is to stick a pry bar in there and carefully work your way around all of the finishing nails to pull the trim off.


To our surprise, this baseboard is actually two pieces. There’s a small decorative piece at the top that came off with just a little patience, but the bottom board is plain and attached much more firmly. I think I’m going to get them off, but I had to call it quits for today. 

Another surprise from the house is the number plate.


What’s up with that? 


Apparently this used to be illuminated! I’m not sure if it’s on a switch, or what. It wouldn’t work very well with the numbers that are on the glass right now. I’ll need to do some work to get some back-lightable numbers, in case I ever get the illumination back.


12-16 volts… that means there’s a transformer in the wall somewhere! Next time we go back I will bring a multimeter to see if it still works. 

Bedroom Update 1

One of the first places we got to work was the bedroom, the one we want to be our room. It’s the one without water damage, and it is the farthest from neighbor’s houses.  Over the last few weeks we have stripped off all of the wallpaper and have prepped the walls for plaster repair.


Rookie mistake, we forgot to put down plastic first. We plan to redo the floors before we move in, but…. it just wasn’t good.


Better… for it all cleaned up, plastic down, as now we start on the molding. We spent about 10 minutes trying to sand it, and it was a stupid gummy mess that wasn’t going anywhere. Now we’re using Citristrip.


It goes on like spreading jelly, and it doesn’t smell too bad. I don’t bother with anything but safety glasses while applying it, but I use rubber gloves and a respirator while scraping it off.


This is what it looks like after two rounds of citristrip, and some rubbing with a scrub pad soaked in mineral spirits. We think it might be worth doing it all, and staining it. 

That’s going to take a while though! My P100 respirator wasn’t doing anything for the fumes, so we took Penny out to Orchard Supply and picked up some cartridges rated for organic vapor. After getting some box fans for enhanced ventilation I might get to keep some brain cells. 

Bonus picture of Penny in her OSH gear!

Bathroom update 2

This is just a mini update, but I was too excited at seeing the tiles that Kaitlyn picked to not post something! 

The contractor is still hard at work, and we are making sure that we have received all of the bits and pieces they need. The bathroom fan is installed, the replacement sink is delivered (and not shattered like the first one!), and all of the shower fittings are accounted for. I verified that the toilet’s waste hole has been relocated to move the toilet flush against the wall, so we won’t have any heartbreak moving it again. The next milestone is plumbing inspection. 

We are still waiting for our high efficiency toilet to arrive Monday, and I think that Katitlyn is picking up light fixtures from UPS this afternoon. 

Bathroom Update 1

We’re going to have a few fast updates this month! One of the very first projects that we’re tackling before we move in is the bathroom. We are spending a major  chunk of our house prep budget on a contractor to get it done quickly (and right), but there’s only one bathroom in the house so we wanted to get it taken care of before we’re living there and before we have the floors refinished. Here’s what the bathroom looked like yesterday:

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50s/60s style vanity, and whoever lived her last really liked towel racks

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This will be part of the dramatic before/after shot

The house was built in 1927, and our best guess is that the bathroom was renovated some time in the 1950s or 1960s. The floor was tile, but all of the green ’tile’ that you see is some kind of plastic. It wasn’t in terrible shape, but there was a bit of water damage and rot in the tub area. It seems like the toilet was replaced some time more recently, based on the strange spacer behind the tank.

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The tub with water/hammer damage

One contractor told me that the wall was totally rotten and bad, and would definitely have to be removed. I didn’t know much about old houses at the time, and he stopped communicating well, so took a hammer to the wall and had a look to see what was behind the tiles. It turns out that it really wasn’t that bad, so although it was going to have to get busted up to do anything with plumbing and electricity, it probably wasn’t in imminent danger of destroying the house due to water damage. Regardless, we were committed. Redoing a bathroom is messy and tends to put it out of commission for a couple of weeks, so here we go.

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The bathroom, today

Today demolition started, and it honestly looks like they demolished most of what they needed to demolish. The upper dividing wall above the shower curtain is gone, everything is down to the studs, the tile is out and hardiebacker is down. So far so good!

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Tile debris, 2017

I was worried that the backing under the tile would be so thick that we would end up with a significant level mismatch between the tile and wood, but as thick as this is I’m hopeful that they’ll get close to a match.I don’t understand how the wire mesh worked structurally, but the floor seemed to be in decent shape after 90 years. I’m just hopeful that what we’re putting in now will last as long. My lovely wife Kaitlyn picked a really cool tile pattern to replace it, and I’m looking forward to a bold reveal post.

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A note from under the flow

Is this a time capsule? I think it may have been a piece of packaging from bathroom accessories that fell beneath the cement when they started making the bathroom. I don’t think it was worth digging out and deciphering, but it was interesting enough to get a picture.

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Here’s another piece of the house’s history. This is one of the light switches, and it appears to be not original, it appears to be grounded, and… maybe not connected to any knob and tube? One of the things on my to-do list is to get an electrician in here to check everything out and see if any of the knob and tube wiring is still live.

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knob and tube in the bathroom wall

This one *is* a piece of knob and tube wiring, and it was attached to a two prong outlet that was hidden behind the vanity. It looks like it was cut off a long time ago, and the outlet had what was probably an original 1927 unpainted brass cover plate. It’s neat to see, and I hope that it’s also good to find this kind of thing and see that people working on things in the past didn’t leave too many scary kludges in the electrical system.

That’s all for tonight’s bathroom post tonight, so here’s a shot of Penny exploring our place!

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Room equalization

This is a topic that I’m still fairly shaky on, so anybody out there reading this as a possible reference should probably take this all with a grain of salt. After building the LX521 speakers I could tell that they weren’t delivering precisely the sound that I know that they’re capable of when they’re set up correctly. As you’ve probably seen in photos, Siegfried Linkwitz’s home does not have any visible acoustic treatment, just some normal ‘stuff’ around the room. Furniture, a nice rug on the ground, nothing like walls full of acoustic foam or avant garde looking diffusers. It’s just a regular room, and most people who build his designs agree that you don’t to do anything special to get the good sound.

Before we go too much farther, I should say that there are two different things that I’ve noticed about the sound in my system that differ from what I heard when I auditioned the original. First, I hear a bit more of the room in the bass response than expected. Things boom/echo just a bit, and its’ the difference between a natural sounding reproduction of a sound that can truly fool you, and the sound of a speaker in a room. We’re not *quite* there yet, though it’s miles better than what I had before. The second part is that there’s a bit of imprecision in the imaging. In the demo I could very plainly localize sounds in space, like I could hear a xylophone player moving up and down the keys and tell the left/right position of each key. That might sound like a wild claim, but that’s what I heard and what convinced me that this thing was worth building. Having my TV between the speakers may be hurting the sound a bit, but I think there’s more that needs to change than just that.

I’m setting out to learn how to improve the sound of the speakers in my room, and I want to be able to do this well enough that when we eventually move I’ll be able to repeat the process with a reasonable certainty that I’ll be able to make the stereo sound good there too. I’m using a program called Room EQ Wizard (REW) to perform measurements. I use a Behringer ECM8000 room measurement microphone that I’ve had for years, a small powered mixer, and my computer sound card to capture the sound. Based on the reputation of the microphone and a loop-back measurement that I did with the rest of the signal chain, I think I have a fairly accurate measurement system…. if I can figure out how to use it right.

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For my first measurement I put the microphone on a tripod positioned at the spot where my head would usually be, and ran a test sweep from 20hz to 400hz. I did a few more, but for the purposes of room equalization I thought that I was interested in things below 200hz.

raw measurement

The first thing that you’ll notice is that this response looks totally ragged and nasty. It’s hard to say exactly where the average is if it was ‘flat’, and there are clearly peaks and dips of 10db. That’s partly because this is a real in-room measurement, the room isn’t treated with much of anything, and it’s like a big echoing box. Concrete floor, flat ceiling, thin rug that doesn’t cover much, and not much stuff on the walls yet. Regardless, there are some good things about it. The response doesn’t drop like a rock below 30hz, and I can tell you that the woofers really made some impressive sounds in the mid 20hz range. The system can do bass, but the room still needs help. Lets see what we can do.

After collecting this data I opened the REW equalizer window, and I selected “miniDSP” as my equalizer so that the program would know what it’s allowed to do in terms of suggesting correction. I assume that some of the other selections have more or less EQ bands available. Next I had to come up with the ‘target settings’. This is what tells the program what you want the ideal system to do. I have some trouble with this one, knowing what to set. I think maybe this is where a sweep to more like 20khz would have given me more information about where the average is supposed to be. Regardless, lets give this a shot.

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I picked 72db as a target level, set the target as flat with a 24 db/octave rolloff at 20hz. For a full range equalization I hear that you are supposed to set a gradual rolloff above 1 to 3 khz, but I’m mostly interested in taming room modes here, and those are all well below 1khz.

In Room EQ wizard I clicked on the “filter tasks” tab and then “match response to target”. It twiddles things around for a second, and then gives five parametric EQ settings that shifts the response to something closer to the target.

target response

Here you can see a brighter red line that is closer to the blue target, and a brownish line that’s the original response. The bright red line is the predicted response if I load the EQ settings. I’m able to save those to a text file and then use my MiniDSP software to read those, or I could enter them manually. Clicking “eq filters” let me see what those are; they looked like this:

filter suggested

Overall it’s a few sharp cuts at specific frequencies, and a broad boost at 40hz, giving the flatter response. I loaded these into the second configuration slot on my MiniDSP, and now I can flip back and forth between the unmodified and equalized versions. That has been very interesting.

Subjectively it sounds as though most of the room ‘boom’ is gone. However, I still somewhat prefer the unaltered version. The equalized version seems to take too much of the bass away. That may have to do with my target curve, or it may have to do with the settings when I clicked “match response to target”. The MiniDSP 4x10HD allows four configurations to be stored, so I could even try a few different versions and audition them each without leaving the couch.

I’m going to hopefully meet with some local audiophiles to discuss this more, and when I get a chance I’ll repeat the measurements with a few changes. Other than dialing in the available EQ, I think that my next step might be to hang up something cloth on one or more walls to absorb some of the sound that’s bouncing around. It’s a lot to research, but I’ll keep reporting back as I figure it out.

 

LX521 Speaker build- the Hypex multi-channel amplifier

It’s about time I had an update! This is basically skipping to the end from the last post, building cables, but I’ve been pressed for time in getting them built so I didn’t keep blogging as I went. I have a few pictures of putting the cabinets together, but it’s boring. I didn’t design that part, and I’m not a master craftsman with fancy insight into how you’re supposed to do woodwork. Hopefully the amplifier is a little more interesting.

The LX521 is a four-way speaker with an active crossover, which means that a pair of them need a total of eight amplifier channels. In order to provide uniform sound, all eight channels need to be identical. The amplifier that the designer uses is the ATI 6012, a 73 pound monster that costs about $2800. It’s an excellent piece of gear, but I was trying to keep the budget a bit more reasonable. A pair of Outlaw Audio Model 5000 could have also worked for about $1200 total, but then I’d need to put two 50 pound amps someplace. For just a little more than that I was able to put together a 25 pound amp that keeps everything in one box, and theoretically measures a little bit better. Also, I think that the more you build for yourself the more fun it is!

The amplifier I put together is based on a Hypex UCD180HG class-D module. I couldn’t really figure out precisely what their fancy voltage regulator upgrade would do for the sound, so I skipped it. If you have a dedicated listening room with soundproofing and are *really* into this stuff, then maybe you can give them a try (or go hog wild building with the Ncore modules). Now that I’ve built it I realize that this is dumb, but I used two of the 1200 watt switching power supplies, the SMPS1200A180. There is no way in hell I need that much power. Maybe I could throw a rave some day, but for now it just means that I have a bottomless pit of reserve power that I’ll never touch. By my best estimate, as loud as I’ve turned it up I don’t think I’ve used more than a few dozen watts yet. Hey dad, that means you could run these off of a solar panel pretty easily!

Anyway, on to the case and construction! I used the Modushop Mini Dissipante as the basis for the enclosure. I did some calculations of waste heat and fin area and all of that, and I must have messed up a decimal place or something, because I definitely didn’t need all of that cooling area. Oh well, I guess the parts will just last longer since they run cool.

The finished amp looks like this in my living room:

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It’s just a plain aluminum panel with an on/off switch. Minimalist, right? The next step will be to make the guts look so nice.

The amp modules have a blue aluminum T-shaped piece with two M3 holes tapped in it. I decided to put all of the holes into an interface plate, and then bolt the plate to the heat sinks. First I drilled and tapped some holes in the aluminum heat sinks, as shown here: note that I used an old T-shirt to protect the kitchen table, and the glass of beer with a lime in it was in fact a mexican style beer by the local brewery, 21st Amendment.

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Next I laid out the interface plate using some calipers and an automatic center punch to give even spacing. You can see that tool in the upper left corner of this picture. This is really useful for achieving a medium level of accuracy in an apartment with hand tools. It’s not like when I had a techshop membership and would do this stuff on a mill, but it at least keeps the hole positions accurate enough that I can generally get them to line up.

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There are two 1/4-20 pan heads at each end of the interface plate, and if this were going to have a really significant heat load then I would have used more of them (and a different head) to ensure solid contact along the full length of the heat sink base. It was reasonably convenient though, and I’m not producing that much waste heat, so i thought it was a corner worth cutting.

The power supply module comes with six M3 screws already installed, holding a compression piece against an L-shaped plate. You have to take these out in order to have access to tapped holes to get this face against the heat sink interface plate. You could mount another way, and the manufacturer even says you can just let this thing hang out in free air, but I know that if I keep things cool they’ll last longer (like to pass down to my kids some day).

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The amp module is surprisingly small for something that can do 180 watts and drive a one ohm load. I slathered on the heat sink grease before attaching them to the interface plate.

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Once they’re all mounted it’s ready to mate up with the heat sinks assembly. You might be able to see that I did some really rough and rowdy countersinks to get those M3  screws to sit flush below the surface of the interface plate. I have some slight concern that some day one of them could be pressed against a capacitor and wear through from vibration and short something out, but probably not. I’m just documenting that concern in case anybody cares, and as something to think about for next time.

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I know you wanted to see this all greased up. Look at those nasty countersinks! Eww!

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There it is! Four 180 watt modules with a 1200 watt supply, all ready for assembly.

And…. Oops. I built them the same, and that’s not going to work for wiring. I had to redo one of these.

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This is a really useful tool that I wanted to take a minute to talk about. This is a ratchet offset screwdriver, and it lets you reach into tight spaces that a regular screwdriver can’t reach. A well designed product won’t require this, but sometimes the designer just can’t be bothered to think about tool access… so that’s when you break this out. The best one I know of is what they used to work on medical linear accelerators at Siemens, and it’s the Chapman. You’ll notice that compared to mine, the ratchet area is much smaller, and the divisions between ratchets are signficantly smaller. That lets you reach into smaller spaces and tighten screws when you don’t have space for much rotation.

This is how I connected the mains power to the front panel toggle switch. It’s a DPDT switch rated for 20 amps, and I made sure that it was large because I wasn’t sure what kind of inrush current the power supplies would draw. As it turns out, they seem to have a nice polite soft-start, or else their inrush is much smaller than the spec sheet indicated because they’re just getting US voltage instead of the 230V that europeans are working with.

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This ended up being a little easier than I expected. The power supply sends a few leads over to the terminal blocks, and each amp takes a positive, negative, and ground input for power. The worst part was all of the crimping. I think I ended up doing about a hundred crimps. There’s a reason they make machines to do that.

In the lower right of this image you can see the twisted pairs of wires going to the speaker output jack, and the black cables soldered directly to the XLR jacks. I need to go back and get everything twisted and trimmed more appropriately before I’ll say I’m done, but for now it works.

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The last thing I did was put channel numbers on each of the amps so that I can keep things straight, and I checked a test signal on each to make sure it wasn’t putting out a measurable DC voltage and a full range music signal sounded right with one of my old speakers. During this step it was really promising to hear music coming out of my old speaker that (I think!) sounded better than the eight year old cheapie receiver that had been driving them.

One thing you’ll notice here is that I used blue paper painter’s tape as a temporary measure to keep anything from shorting out. The maximum voltage in here is 48 volts relative to ground, and 96 volts from the positive to negative terminals. Everything is firmly connected to screw terminals inside of insulated blocks, but a little bit of metal peeks out at the edges, and so I didn’t want to take any chances on something shorting out. The end goal is to have the terminal blocks bolted to the bottom panel of the enclosure in a neat row so that the wires can be routed in a clean and proper way.

The 120V mains line goes to the switch on the front panel using a tightly twisted pair of 14 gauge wires in some ring terminals. I used fork terminals for the rest, but for 120VAC I used insulated ring terminals so the screw would have to fall completely out before the crimped part could fall and contact something else. The rear panel has a three-prong jack, and there’s an earth ground that’s similarly connected to the chassis (you can make that out in the photo above).

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The back of the amp looks fairly neat thanks to Front Panel Express making the panel for me. The large cutouts in thin aluminum and added threads saved me a *ton* of work, and I know they made it look nicer than I could have. I’ll add more labels when I’m done, but for now I know how they’re laid out well enough that a prompt of “1” and “2” is enough that I won’t plug something in wrong. If I did do that, it would blow up my tweeters.

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Ok, so that’s all I’ve got for now. I’ll leave you with a cell phone picture of the speakers and amp in the living room. They sound pretty good. I hope you’ve enjoyed reading!

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LX521 build- speaker wires

This is is the very first post in my LX521 build, not counting a couple of background posts saying what I’m building and why I’m building it. Tonight I got started on making my speaker wires. The LX521 is a four-way speaker with an active crossover, meaning that for a stereo pair I need eight amplifier channels and I need to plug in a total of sixteen wires in the correct fashion or I risk blowing up some drivers. If I swap the tweeter channel with any other channel it will probably destroy the tweeters right away. If I switch any of the others it might not break them right away, but it will sound very wrong. If I flip the polarity of anything, it will sound wrong but I’ll probably have a hard time putting my finger on it at first.

One way to tackle this would be to get a bunch of the typical binding posts that you see on any speaker, and just label everything carefully. That’s a little tedious, it takes up some space, and it won’t look very good. Another way to do it is to get a speaker cable with eight conductors in it and use a single plug with eight terminals. I got a set of 8-pole Neutrik Speakon connectors, and once I get those set up correctly I won’t have to worry about it again.

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The connector has eight bars around the inside and outside of the barrel that are locked into place when the connector is inserted into its receptacle and rotated about a quarter turn. They’re rated for 30 amps per contact and 250 volts, so one of these plugs could pass over 25kW of musical power if it had to. These are commonly used for the kinds of speakers used at concerts. They’re overkill, but they were basically the same price as using four times as many of the regular connectors.

It was a little tricky to figure out how to assemble them at first, but it’s not so bad. They have eight screw terminals to accept the wires, which is nice because I don’t have to crimp or solder anything.

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I wasn’t able to find any eight-conductor cables sold in small quantity, so I’m just going to double up on some four conductor wire from monoprice. I don’t think that it’s terribly important for the wire pairs to be individually twisted, but I do plan on running the tweeter and sub channels through two different lengths of cable just to be safe. I’m putting the two lengths of cable through some Techflex to keep them tidy.

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I consider all of this to be a safe level of overkill, even though it’s by no means the pinnacle of what could have been done. It’s a twelve foot run of 14AWG stranded wire, so that should add about 0.06 ohms of resistance in series with each driver. The woofers will be in parallel and will present a two ohm load, so this is about 2.5% of the speaker impedance. Because this system uses an active crossover the increased resistance won’t have an effect on the crossover frequency or slope, but it will attenuate the woofers by about 0.2 dB. The mids and tweeters are 4 and 8 ohms so the impedance will affect them less. When I’m done I may measure the inductance of the cables to verify that they’re not causing any rolloff in the tweeters, but that’s it. A lot of speaker cable vendors go on about all kinds of magnetic/metallurgical voodoo, but I work with a lot of electrical engineers with PhDs who spend all day designing and building sensitive high performance analog circuits, and I have never once heard them talk about the kinds of things that audiophile speaker cable companies base their products on. As far as the EEs are concerned, a wire has resistance, capacitance, and inductance. If anybody out there wants a really honest measurement and has some expensive cables, get in touch and maybe I can bring them to someone who knows how to use the fancy equipment so that we can compare.

I think that’s probably enough posting about speaker cables, you’ll see more of them when it’s all installed. If you want to read a real EE’s opinion, go back to Linkwitz.

Just a few details on the build… It is a little hard to see the markings on the black plastic  that say circuit and polarity, so I marked up an image.

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For my build I’ll do:

1 – Tweeter (green circuit, cable 1, red positive, black negative)
2 – Upper mid (yellow circuit, cable 1, green positive, white negative)
3 – Lower mid (blue circuit, cable 2, red positive, black negative)
4 – Woofers (red circuit, cable 2, green positive, white negative)

Lets hope I don’t cross any wires!