Clarity on Seas Thor Kit

[planet10]

Originally Posted by ichiban

In the 1970s, Joseph D'Appolito created an acoustical array of two mid/woofers symmetrically arranged above and below the tweeter in a vertical alignment.

Joe's AES paper was Fall 1983. So the above should be "In the 1980s,"

I built my 1st one of these in 1975. A pair of Harbeth 8" woofers & a Philips tweeter in a triangulated TL.

You can get around the issues that 6 moons brings up by using a tweeter that can XO really low. 300-500 Hz pushes the XO into an area where wavelengths are long enuff that the physical separation isn't an issue.

dave

[ichiban]

Originally Posted by planet10

You can get around the issues that 6 moons brings up by using a tweeter that can XO really low. 300-500 Hz
dave

Any suggested low distortion tweets, that can cross at 6dB/Oct. ?

[planet10]

Fostex FF85KeN, any of the 2nd generation Mark Audio Alpairs. 6 or 7 would be my choice (i'm extrrapolating on the 6 -- Mark has only made prototypes so far, the 7 is eerie good, at least as good as the FF85KeN, but more dynamic capability & higher efficiency). Also still made with promise to continue to improve).

dave

[ichiban]

Thanks, Dave.

[x2turbo]

First off I've read thru numerous thread here and at HTGuide and I want to thank everyone for all the excellent info that this newbie is trying to digest.

I'm planning on building a pair of Odin's for my office. The various recommended Thor cabinets are just too big for my space. I'll initially be driving them with an Emotiva XPA-2 borrowed from the HT, but will probably purchase a pair of UPA-1's in the near future. I'm going to have Madisound build the LR4 XO's since I live in the same town and don't have that skill. Luckily I've built quite a few built-in cabinets throughout the house and have all the tools necessary to do the woodworking.

I have a couple of questions based on what I've read.

Jimangie has stated that he has stuffed his port so that they are basically sealed. I'm planning on using the standard SEAS Odin design spec.

1) Should I fore-go the port entirely or should I keep it to allow for some flexibility?

And lastly, someone stated that they were working with Madisound on creating a XO to Jimangie's LR4 design, but Madisound wasn't able to match it perfectly based on parts availability. It also sounded like Adam is the guy to talk to.

2) Was a suitable design based on their parts availability reached by anyone to serve as a guide?

Thanks again for everyone's contributions to this thread. It was a long read and I was up 2:00am last night doing so, but it was also very informative and interesting.

Greg

[jimangie1973]

I'm running mine completely sealed in a 1.2 cu ft cabinet 10 inches wide with a 1/2 inch roundover on the sides of the baffle. The bass is pretty good but a sub definitely improves things. I think the modeled bass response has a -3dB point of 50 Hz.

1) If want to go with the port, make the cabinets as big as you can. You could then play with the port length and dampen it further with cotton or similar if bass is too fat. I would recommend the cabinets 10" wide with the 1/2 inch roundovers as mine are.

2) For the crossover, Madisound should have all the parts needed. You can use the 14 AWG Solen inductors. If you're interested, I have another LR4 crossover design which crosses at 1.5 kHz. It has a few more parts than the 2 kHz LR4 design but it theoretically has lower distortion due to the 3rd harmonic peak at 1.6 kHz further attenuated. Both LR4 designs sound good.

[x2turbo]

Thanks for the quick reply.

Unfortunately I already cut the blanks yesterday since I had some MDF lying around and some spare time. The box has a 9.5" baffle and is 1.18 cu ft without a brace so I think I'm going to go the sealed route. I'll cut some holes in the brace as well.

If I don't like it I can always build a bigger box and put a port in it. The practice won't hurt me. Ultimately I want to replace my 20 yr old Vandersteens in the HT with Clearwave Dynamic 4T's and the Odin's are practice before I build something bigger.

I'd be very interested in your 1.5Khz crossover design if you can point my towards a schematic. These first XOs I plan on having made for me, but I'd like to make my own at somepoint, but for now baby steps.

I'll be sure to post my thoughts once they are finished.

Thanks again for your help,
Greg

[jimangie1973]

You may want to do a 2" flared port in the back. You could then start with a long length and cut it back and possibly dampen it to where the bass sounds right. This would give you flexability with the bass response. If you go sealed, you have only one option.

Here's the schematic for the 1.5 kHz LR4. I'll post response plots tomorrow.

I bought parts for this at Parts Express. Not sure if Madisound can make the 0.025 mH inductor.

In my crossover, the 3.6 Ohm is a 5.6 Ohm in parallel with at 10 Ohm, the 8.7 uF is an 8.2 uF in parallel with a 0.5 uF, and the 22 uF is a 20 uF in parallel with a 2 uF.

[jimangie1973]

Response / Reverse Null

[jimangie1973]

Impedance / Transfer Functions