My first 3 way speaker build

[mattsk8]

Edit: I guess technically it should be "My first 3 way speaker design", not build.

My goal here is to prove that you can take fairly expensive, well received drivers and make them sound bad :p. Kidding, hopefully this doesn't play out that way; thankfully I will again be guided through the measuring and crossover design process by the wonderful guys at Meniscus Audio .

I need to thank Craig Kinnison in a big way for helping with driver selection on this project, I've been all over the place for about a year now trying to put it together and he helped me nail it. For drivers I'll be using the following...

SB Acoustics SB29NRX-6

Scanspeak 18w4531
Scanspeak HDS Tweeter

I don't need to measure the drivers out of the cabinets because there's a wealth of info out there for these drivers, so I can get started building the cabinets and measure the speakers in the cabinets for crossover design. Still thinking on how I'll do the cabinets. Per Madisound's recommendations, I'm building the woofer's cabinet 2 cf tuned to 28hz. I think the mid/tweeter cabinet will end up somewhere in the 0.4-0.5cf region. Going to make curved cabinets for these, and right now I'm thinking cherry front and rear baffles with satin black for the sides for a classic look. I'll definitely post pics of progress. These speakers will replace my ER18s, and not because I'm unhappy with those, more-so because I have a speaker building disease :rolleyes:. I'll probably take my ER18s apart and re-purpose the Seas ER18rnx drivers in a TM monitor using the SB Acoustics stac26 tweeters (which will basically be an SR71, just uses a different tweeter).

Excited to get this build started!!

[isaeagle4031]

Re: My first 3 way speaker build

Nice selection of drivers for sure. With your woodworking skills, you will do them justice.

[mattsk8]

Re: My first 3 way speaker build

Nice selection of drivers for sure. With your woodworking skills, you will do them justice.

Thanks Chuck! Once the crossovers are roughed in, I'll voice these with "what would Chuck do" in the back of my mind; I've always loved the sound of your designs.

[isaeagle4031]

Re: My first 3 way speaker build

Well thanks Matt. Be ready for some decent sized parts on the woofer there. I would suspect you will be in 300 hz range on it.

[ani_101]

Re: My first 3 way speaker build

Nice. Well, hope you have a nice journey.

I too am starting on a similar quest... just a bit behind... Have a stockpile of drivers and odds and ends.... need to jump the learning curve and get moving.

Regards
Ani

[Navy Guy]

Re: My first 3 way speaker build

I'm sure it'd be hard to make a bad sounding speaker with those drivers.

[gabel87]

Re: My first 3 way speaker build

This should be a pretty sweet build.

[Tessera]

Re: My first 3 way speaker build

Nice!
I'm curious about how you plan to measure the woofer for x-over design work? Measuring the bottom of 3-ways far field is difficult for me because I must measure indoor and can't get them far enough away from boundaries.

[mattsk8]

Re: My first 3 way speaker build

Nice!
I'm curious about how you plan to measure the woofer for x-over design work? Measuring the bottom of 3-ways far field is difficult for me because I must measure indoor and can't get them far enough away from boundaries.

I'm actually going to rely on Meniscus to help me with that because I've never measured a woofer like this for a passive crossover. For now I'm thinking that will largely depend more on the mid driver's measurements, like Chuck said I'm guessing it'll be crossed to the mid somewhere in the 200-300hz region from the measurements I've seen (I'd like to pull as much out of the Scanspeak as I can so I'd like to go fairly low).

Craig also had another good idea, and that was to put the woofer's crossover as well as the bottom of the midrange's crossover in the woofer's cabinet and have 4 binding posts, 2 in and 2 out. Then design the mid and tweeter as a sealed TM monitor that sat on top of the woofer cabinet, and I would essentially have 2 different designs. I could play the Revelator full range if I wanted to (but still crossed to the HDS tweeter), or set it on the woofers for a passive 3 way (just to have some fun with it). Not sure if I'll do this just yet, I may still just make one cabinet. Either way, my end goal is to have a similar shape to the Sony SS-AR, or maybe Sonus Fabers. I'm building these for my music system.

[isaeagle4031]

Re: My first 3 way speaker build

Hmm I wonder where he got that idea? I've done that a couple of times. The last was my Nathan+ design. I could run them as a 3way crossed at 300ish (simple cap to mid/tweets) or let the upper section play alone where they ran all the way down to about 55hz ported.

[mattsk8]

Re: My first 3 way speaker build

Hmm I wonder where he got that idea? I've done that a couple of times. The last was my Nathan+ design. I could run them as a 3way crossed at 300ish (simple cap to mid/tweets) or let the upper section play alone where they ran all the way down to about 55hz ported.

Did you have any issues related to having the 2 ports (mid cabinet and woofer ports)? I can't think of why you would since they'd be crossed way above anything near the ports frequency, but just thought I'd double check and ask. If no issue, I could build a 0.7cf cabinet port tuned to 45hz for TM cabinet.

[Jay1]

Re: My first 3 way speaker build

Nice!
I'm curious about how you plan to measure the woofer for x-over design work? Measuring the bottom of 3-ways far field is difficult for me because I must measure indoor and can't get them far enough away from boundaries.

I'm actually going to rely on Meniscus to help me with that because I've never measured a woofer like this for a passive crossover. For now I'm thinking that will largely depend more on the mid driver's measurements, like Chuck said I'm guessing it'll be crossed to the mid somewhere in the 200-300hz region from the measurements I've seen (I'd like to pull as much out of the Scanspeak as I can so I'd like to go fairly low).

Measure the woofer at the same distance and drive level on axis as you do for the T/M (something like 24" is plenty of distance). Set the gate like you normally would to filter out all of the low end room related junk and save that curve. Now measure the woofer nearfield and adjust the level so the curve overlaps at the frequency your gate from the previous measurement starts. Save both curves. Use print screen and MS paint to remove the garbage and run the combined curve through SPL Copy. If there's a low frequency noise floor in your measurements like many people have you can also run the results through response modeler to add a filter that removes the junk.

You will need to do this for your mid as well. That noise floor in the mid/tweet measurements will throw off the phase in your x over sim.

[dcibel]

Re: My first 3 way speaker build

Nice selection of drivers. I'v been enjoying that tweeter for several years now, it is really excellent. Low moving mass, low compression.

[mattsk8]

Re: My first 3 way speaker build

Nice selection of drivers. I'v been enjoying that tweeter for several years now, it is really excellent. Low moving mass, low compression.

Good to hear! Those were Craigs recommendation. I've never heard them, but Craig has a pretty good idea of what I like and don't like from the different times we've hung out, so I'm excited to hear those.

I've had my eye on that SB woofer for a while now and wanted to try it, I've heard it's very "musical" and everything about it looks good on paper.

[Mike220]

Re: My first 3 way speaker build

Good luck Matt the drivers all go together pretty nicely. Wish i could say more intelligent things but my brain is mush from veneering all day.