SR-71's Seas ER18RNX 7" woofer sold out at Madisound :( Other 2-way suggestions?

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SR-71's Seas ER18RNX 7" woofer sold out at Madisound :( Other 2-way suggestions?

My wife was buying me this for Christmas and we were waiting for it to ship:

Unfortunately, we get an email the next day from Madisound saying that the 7" woofer from the SR-71 kit is sold out. The sales person was asking my wife if she wanted a suggestion for another 2-way instead.

I'm wanting these for my HT setup (Rotel RMB-1095 amplifer, RSP-1068 preamp) and I like big sound so I don't want to go smaller than a 8" woofer for the mains really, but 7" was the largest I've seen in a 2-way. This is probably because any larger than 7" for a 2-way and there's a balancing issue I suspect. I'm planning on purchasing two more kits for my surround, center, and center back. My dad was about to purchase three of these kits for his own HT setup. I know that John (from Zaph) suggests to not use these on a shelf/bookcase, but I was going to set the front left-right pair on this: (just the bottom console part, the hutch will not be used). I figure I'd want to decouple the speaker from the furniture's surface. It's interesting that most DIY designs are made for stands, but I'm not a fan of them anymore since little kids come over and play in the living room (could knock over).. plus, it's hard to justify the extra width taken up by my 65" tv on the wall I'm using. After building the SR-71's, I wanted to then order the other two kits so I can make the other speakers. The only reason I wanted to do that was because I thought it would be best to keep all speakers matched in this setup (I'd also use it to mix 5.1 audio).

I hate to hear of a company selling out of something. I don't know if they're phasing out the SR-71 kits or something but I suspect that may be the case since the salesperson suggested a different 2-way kit instead of offering an ETA on the woofers.

Has anyone else had this issue lately? I feel crappy because I spent a couple weeks researching the best combination of parts and I finally wanted to get these. Hmm.. so what else is there since I can't get these? My budget is $400 per pair and I want to use the speakers for HT and also SACD listening.
I was hoping they would designate a pair of ER18's for each kit so that they would be available when someone placed an order. It sounds like they just pull an ER18 off the shelf to fulfill the kit, which kinda does make sense logistically. Perhaps someone that ordered some single ER18's could fill us in on the backorder status if there is one?

Should I wait for this kit to be complete or should I substitute a similar parameter woofer in its place? Bad idea? I did like the fact that it was a "kit."

OH yeah, I was wanting to ask if anyone has taken a kit like this and "added" another chamber to the speaker enclosure for a subwoofer (~10-12"). FULL range mains sound really good...
buttfacelicker said:
Should I wait for this kit to be complete or should I substitute a similar parameter woofer in its place?

My comments, for the little that they are worth.

Based on a very brief listen to my current project using these same drivers (in MTM), I'd say that the ER18 is an exceptionally good driver and I suggest you wait for them, hard though it may be.
Also, my modelling of my design shows some small 'issues' that I may want to look at in the voicing process. Though the speakers are different, similar issues have already been identified and sorted by Zaph for the SR-71; so I'm confident that by staying with the proper design you will have a well supported, well developed project that will be easy to voice to a very high standard.
Ray Collins said:
How did you arrive at that conclusion?


Like I said, it's just my humble opinion... based on two things:

1) The ER18 has a lower x-over point on a better behaved woofer. On the L18 it still shows some of the 8khz breakup... be it 30db down, but it's still there...

2) The ER18 has slightly lower harmonic distortion.

You could say I never heard either one... But like I said... on paper the ER18 looks better to me.
No, no, that is quite enough data...I understand. My wife's pet name for me is less flattering and used when I am obstinate...which is is F'''er Head. Obviously she does not know how to work in obscenities; however, I must admit her application is effective and spot on.

peter_m said:
Sorry to barge in like this, but when I first read your screen name, I assumed it had something to do with a pet dog... I'll spare you the graphical explanation... I'm glad it's not related to your family pet, LOL!


Oh, I think there's petting involved - but that's a subject for a different kind of forum.

can you type with one hand?
Glad to hear your parts were shipped! Keep us up on your progress.

I would also like to try the SR71. I would like to use the Madisound crossover and build my own boxes.

Can anyone tell me if it would be OK to port these out the front as long as the box volume stayed about the same and the port tuning was kept close?
Well, in order to do that you would have to make the baffle taller and then to keep the volume the same make the box shallower (front to back) which I think would interfere with your port length because you need a sufficient amount of space between the opening on the port and the back of the box. I don't see it working out, but you could always recalculate the box volume and port, but keep the baffle width the same. I think that as long as you don't change the baffle width you will be ok to use the same crossover.
I drew up a quick sketch to help explain what I'm thinking of.

An externally hosted image should be here but it was not working when we last tested it.

I use WinIsd for the box and vent dimensions. Zaph said the box would work well around 16L & 40hz so thats where the 18X11X9" came from. He used a straight 2" port at 6 or 7" long out the back.

I want to port out the front. I have read that a larger dia port 3" will produce less port whistle? thats why I would like to try a 3" at 18 to 18.75" long. This length would cause the port to have a 90* bend to fit in the box.

Please let me know if I'm way off base here. Maybe this is to far from the original design to work? Maybe having the opening to the port behind the woofer is a bad idea? Maybe having the woofer on bottom the tweeter in the middle and the port on top creates some odd sound qualities? I don't know?

WinIsd worked out the a 16L box tuned to 40hz at ( 18" X 11" X 9" with a 18.5" long 3" port).

Thanks for any help!!!
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