seas thor crossover redesign help

[HiFi Si]

A bit of a late question - I hope that this thread is not dead!

I was a bit of an early adopter of the Odin and built the early design with the W17-E002 drivers and Millenium Tweeter. I went with a xo design that was faxed to me by Seas USA, upon an advisory from Madisound about concerns with the original design. I also upgraded to Alphacore Inductors and Sonicraft caps..

I am keen to try Jim's design, but of course I have the question about compatibility with the W17 drivers, which have slightly different T/S parameters...

Does anyone have any advice on this?

cheers

Simon

[serioushifi]

Copying Jim's latest crossover here for continuity.

Sorry which speaker is this for? The ODIN or the THOR?

This one is totally different? Is this for the ODIN?

[serioushifi]

Anyone? Would like to order the bits for the correct 'improved crossover'

[tktran]

As you are probably aware, both original SEAS Odin Mk3 and Thor have the same crossover, just different cabinets.

The first crossover pictured in the above post (with 1.2mH series woofer inductor) is a LR4 1.9KHz crossover that user "jimangie1973" designed for a commercial speaker which utilised SEAS W18E001 (with rubber boots) and T25CF002 drivers in a cabinet with the same baffle layout as the Odin, but slightly wider width (10" vs 9.5") and sealed with 1.2 cu ft (Odin mk3 is vented). Jim developed this crossover sometimed in 2007/8.

A few comments (all IMO) if I may. There may be some variations of the first picture floating about, because you can basically tweak the tweeter level to your own taste by adjusting the series tweeter resistor (4.235ohm). A fraction of an ohm can make a difference to a tweeter that calls out "hey everybody listen to me" and one that's never calls any attention to itself, but the treble is still all there.

The parallel woofer inductor (0.05mH) is responsible for notching out the magnesium cone resonance of the W18E001, and may need some fine tuning. This is because the resonance have wandered over the years, according to some reports (and publicly available measurements). In my own W18E001 (copper plated motors, no rubber magnet, earlier production year), I found that I had to unwind my inductor to 0.045mH to knock the magnesium cone resonance right on the head. Of course YMMV.

I'm not sure what that 2nd picture posted above (2mH series woofer inductor) but if I recall correctly, it was a drawn version of one of Jim's ealier crossover iterations, because Jim's original crossover is a text document and difficult to for some interpret.

Now a couple of years later Jim developed another LR4 crossover, crossing over at 1.5KHz. Jim reports this as sounding slightly better. This is the recommended crossover, if you were to build one today. It's posted here:

http://www.diyaudio.com/forums/multi-way/64799-clarity-seas-thor-kit-100.html#post2240904

I have yet to try the 1.5KHz crossover, due to lack of time, but also due to satisfaction with the 1.9KHz version. The midrange and treble is more natural and far more realistic than the original Thor crossver. Also, my cabinets have been redesigned to be vented, and tuned at 32Hz. It gives incredible in room bass response to 30Hz. The original Thor is thin in comparison.

To the other poster- FAQ #9543: No, you cannot use a W17E002, as it is a completely different woofer.

regards,
Thanh.

[serioushifi]

Thanks thanh,

Much appreciated. I am wanting to build the odin cabinet and keep the flat baffle surface area the same, but have a rounded 24.5mm surround. The baffle will protrude the front of the cabinet and will be 25mm thick. Will this disrupt the BSC much? The actual flat surface and driver mounting position will be the same as the original design.

[johngalt47]

I don't know if any of you followed the different types of Thor builds on diyaudio but it may be worth a look if you have not.

[JCC]

Hi All,

This may take a couple of posts. I wanted to tweak my crossovers so I decided to simulate them so I could see what changes had what effect. The problrm is that my sims don't look anything like Jim's and I can't figure out why.

I took Jim's FRD and ZMA files for the Seas drivers from page 1 of this thread (posts 28 and 29). I used those in Jeff Bagby's PCD software to simulate the crossover shown in post 227 above with the 5.7 cap in the tweeter circuit. I don't get nearly the same results as some of those above. In particular the crossover frequency is higher and the phase response is not good compared to what is shown in post 45 or 128 above. (I think post 34 is a different crossover.) I must be doing something wrong, but I don't know what. Can someone comment. I will do another post with a different crossover version.

[JCC]

Continued:
Next I simmed another vesion of the crossover with the 8.7 cap in the tweeter circuit. What I got is attached. The crossover point is lower but phase response still is not good.

Finally, I tried modifyng this version of the crossover to get better phase response and came up with the second set of attachments.

Could someone "check my work" and see if they come up with similar results or tell me what I am doing wrong.

[JCC]

One more with the last part of the circuit since I can only do 5 attachments

[JCC]

One last thing: If it helps, you might look here for Jim's response charts with the 8.7 version of the crossover. The basic frequency response looks similar to mine, but not phase.

http://www.diyaudio.com/forums/multi-way/64799-clarity-seas-thor-kit-100.html

[jimangie1973]

Try these FRD and ZMA files. I created these about 1 month ago to adjust the crossovers for the 2 cu. ft ported enclosures I transferred the drivers to.

[jimangie1973]

Here's an off axis measurement.

I'm not sure how those initial measurements were taken as far as relative phase between drivers. These new measurements are definitely correct with regard to phase.

I've verified my sim is correct by doing the measurement with the crossover in place. Both the measured phase and magnitude match my sim result very closely.

Jim

[JCC]

Thanks Jim, I really appreciate it.

Two questions: Are these measurements taken in a baffle like the Thor cabinets so I don't have to do anything to them before using them for a simulation?

What is the latest version of your crossover; the one with the 5.7 cap in the tweeter circuit or the 8.7 cap? What is the difference in how they sound?

Thanks again.

[haugeman]

modification for different tweeter.

Hey guys.

I asked this question ower in the thor thread on DIY audio also, but throws it in here to in hope for a quick answer.

In the shop i work in we sell hifi and home cinema equipment amongst other and one of the brands we sell uses the W18E001 drivers (XTZ speakers), so i can get some good prices on these, and i have some of their speakers in my HT and like the sound of them. and on another totally useless point i am from Norway and live only an hour away from the factory making these drivers :B . This made me look at the Thor DIY kit for my first speaker build.

I got an bargain on a pair of new in box T29MF001 magnum tweeters ( 150$ instead of 770$ :T ) that i just couldn't resist taking. From what i have read here i have decided to build a pair of FAT THOR but i need some help remodeling the xo for the different tweeters.

According to seas, i mailed them and asked, they say i have to adjust the xo for the higher sensitivity of the magnum tweeters.
Is there anyone that can take the specs of the diferent tweeter and adjust the XO to fit theese?

Exept for some car subsencloshures this will be my first DIY speaker, and im total novice in XO construction so all help is apreciated

T29MF001 Spec PDF

The original T25CF002 "Millenium" Tweeter specs


The replacement T29MF001 "Magnum" tweeter specs

[avddreamr]

modification for different tweeter.

Hey guys.

I asked this question ower in the thor thread on DIY audio also, but throws it in here to in hope for a quick answer.

In the shop i work in we sell hifi and home cinema equipment amongst other and one of the brands we sell uses the W18E001 drivers (XTZ speakers), so i can get some good prices on these, and i have some of their speakers in my HT and like the sound of them. and on another totally useless point i am from Norway and live only an hour away from the factory making these drivers :B . This made me look at the Thor DIY kit for my first speaker build.

I got an bargain on a pair of new in box T29MF001 magnum tweeters ( 150$ instead of 770$ :T ) that i just couldn't resist taking. From what i have read here i have decided to build a pair of FAT THOR but i need some help remodeling the xo for the different tweeters.

According to seas, i mailed them and asked, they say i have to adjust the xo for the higher sensitivity of the magnum tweeters.
Is there anyone that can take the specs of the diferent tweeter and adjust the XO to fit theese?

Exept for some car subsencloshures this will be my first DIY speaker, and im total novice in XO construction so all help is apreciated

T29MF001 Spec PDF

The original T25CF002 "Millenium" Tweeter specs


The replacement T29MF001 "Magnum" tweeter specs

I think the only way you may get something like that done is if you sent a pair of magnums over to someone who has sufficient experience with this design (jimmangie), and he felt it was worthwhile to do so. As someone who has spent way to much time tunning a system or two in car audio, the idea of spending a few hundred hours to get everything to work isn't really appealing, and I'm sure he's far for more proficient than I can ever dream of being.

Not to mention the driver doesn't really have current availability stateside, so it makes it an unlikely candidate for a redesign. If you're dead set on building the thors, then buy a pair of the tweets that the design calls for. Chances are you will be far happier that way.

I think that if a driver should be chosen to replace the original, it would probably should be a driver that would have merits in the design... a Scan-Speak 6600 or maybe even on a budget Seas 27TBCDGB-DXT, or switching to the nextel series which have a better midrange and won't require the tweeter to crossover at around 1500hz or below, but either way changing the tweeter would probably require a complete redesign of everything but the box, and at that point why stick with the original driver compliment.

[jimangie1973]

Actually the magnum tweeter is on sale at Madisound. I could probably help you out with it but I would not make any guarantees as far as results. It has a very large xmax so it would probably play low pretty well although I don't see any distortion profile. From the response plot, it looks like it would need an LCR notch parallel with the driver to flatten out that response peak. It would also need to be attenuated an additional couple dB when compared with the millenium.

[haugeman]

Actually the magnum tweeter is on sale at Madisound. I could probably help you out with it but I would not make any guarantees as far as results. It has a very large xmax so it would probably play low pretty well although I don't see any distortion profile. From the response plot, it looks like it would need an LCR notch parallel with the driver to flatten out that response peak. It would also need to be attenuated an additional couple dB when compared with the millenium.

All help i can get is appreciated since i have no previous knowledge of XO construction. if u could bother to do a modification to the improved filter design u already made so it could fit the fat thor design i would be grateful ;x( , or at least an educated guess for witch components to switch or add to the filter.

With the price i got on these im determined to try to get them to work in this design one way or the other :g>

[grakz]

A littel off topic, but have anyone here built a bookshelf TM using Seas W18 and TC25CF002? Thinking about such a project for my cabin stereo. I have the Odins with the updated xover frim Jimangie.

[johngalt47]

Not exactly. I did build one with that woofer but with Dayton's RS28A tweeter. They sound really nice
but require a sub since they are sealed.

[Jonasz]

Hi John,
do you have a buildthread or any more info about your w18/rs28 build?

I bet they sound nice the rs28a is such a sweet sounding tweeter.

[johngalt47]

Yes, it is over at Parts-Express Tech Talk. Wolf named them "Hardanger Gems". If you don't find it, pm your email and I will send the write up.

[Laflamablanca]

Hi, im hoping to bring this thread to life!!
I've just finnished a pair of thor cabinetts, unfourtunely i did it before i came across this forum. i have built the larger cabinetts from seas website. And seas crossover. But now that i have read a bit in this thread, i dont want it no more!!! is there anyone who tried Jim's crossover whit the larger cabinetts?

[grakz]

Anyone still using their Seas Odin/Thor speakers? Have had mine collecting dust in the basement for a year, thinking of refreshing the crossovers and make them sing again.

[wallacefl]

I wonder if just increasing the primary inductor value and thereby lower the crossover point ..to maybe 1800 hz would be a good start?

[agrippa]

Troels in Denmark has some designs using these drivers. He is well respected, check his website out.

[hhildebr]

Hi guys,

silly question: I think I've stumbled across a thread either ehere or over at diyaudio with someone doing a completely new XO for the Thor, but for the life of me I can't find it. Maybe my old brain got too mushy, but maybe somebody knows what I'm thinking of?

Thanks,
Hauke

[Jonasz]

The thread you're writing in?

https://www.htguide.com/forum/showthread.php?26754-seas-thor-crossover-redesign-help/page2

Or did you think of another one?

[hhildebr]

Yeah, something else. I know about the variants of Jim's cross-over, I think there was something else. But maybe my brain's just trying to trick me into bying new parts ;-)

[hhildebr]

Hmm, maybe this was the post I'm thinking of, but I think I'll go with the latest jimangie design. Speaking of which: The latest version I'm aware of is this one http://www.diyaudio.com/forums/multi...st2838726.html. But in his "Curved Thor" thread lanetim referenced a newer version http://www.diyaudio.com/forums/multi...st4225607.html - is that the most recent? Is there a forum post or thread around this, or was that a version communicated by PM?

[leandro girard]

Well almost 2 years sincn regardinge last post! hi to everyone! Im really diging into building a couple o seas odin, but everything ive see XO is for correcting thor XO. Im aware that are the same XO but anybody have build odins with the redrawns of the XO? thanks verymuch!