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vikingshill 5th May 2011 11:36 PM

Problem with Small Thor build
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Hi there all.

My first tread here, and i hope you have understanding in my poor english.

I have built a pair off Small Thor, i plugg it in with my Belles Soloist 3 and 5 combo. 2 x 65 w in 8Ohms
I dont know what to say now, i here they want to sound pure, and i here the low bass, sound like a 12" woofer, i here the treble,, butt i want more and more detail, and i want a lot more upper bass and mor crisp in the mids. barely here the thump in drums, its not there , it feels like the speakers i asleap under a bigg thick blanket. no attack what so ever..
the stereo picture are nice, and i here the dry clean sound. butt something is wrong here ! , i also conected my old Yamaha 430 reciever to see if the amp was the problem, but that did not do any good.
The xover are Jims LR4, the inductors i gott had litle more resistance, butt could that do that much ? mH are spot on and so is everything else.

Any idea ?

Best regard everyone and thanks Jim and all other for very nice reeding about the Thor.

Jay 6th May 2011 05:30 AM

Hmmm... I often hear these issues with transmission lines. Subtle but can be serious for somebody. Stuffing is tedious, but still cannot solve the issues. I solved the issues with my TL (not Thor) with changing the crossover. The midrange response is made a few dB higher.

vikingshill 6th May 2011 07:05 AM

Hi, Yes i thought of playing with the stuffing to, i have them placed in a corner that you can see, will try to stuff it a bit more, and maby damping the port a bit. or start with damping the port.

Jay 6th May 2011 10:02 AM

Your problem is imo should be address with reducing the fill not adding more. But it is difficult once you have permanently sealed the enclosure.

vikingshill 6th May 2011 11:06 AM

the stuffing you see in the pic are 169g/0,37lbs sheep wool , very light stuffed, took some time to make upp the volume off it.
overall electric resistance off speaker are 3.8 Ohms

vikingshill 7th May 2011 09:49 PM

Jay, how did you change your xover ? and do you know what diff it make to play with the stuffing ? or damping the port some, this is a MS-TL , by "scotmoose" if im corect ?

raypalmer 7th May 2011 10:28 PM

Try them in a different room.. just to see.

Jay's right about the crossover. I fiddle and fiddle with every speaker I build, but in the end I change crossover values/architecture and voila! C'est finit!

Jay 8th May 2011 05:15 AM


Originally Posted by vikingshill (
Jay, how did you change your xover ?

I have never had the Thor. But since the beginning I have found something "wrong" with TL sound. I have heard quite a few TLs and they share the same issues. In the beginning I thought it was probably because of enclosure design mistake. But look at everyone with their TLs, they fiddle with the stuffing a lot to get it "right". Even with TLs designed by D'Appolito and Lynn Olson.

I found that TL is suitable with crossover where the midrange is exposed (I only simulate, not measure). This crossover is not suitable for bookshelf because then you will hear only the midrange and this energy can get "wild". TL seems to have a property to tame this. It's massive build, and probably the physical geometry itself.

Crossover design usually is "independent" of whether the enclosure is TL or not. Leakage, baffle diffraction and of course the low end roll-off slope is treated equally similar. But why the sound is different? I don't know, it seems the detail is lost in the tube. The only logical explanation I can think of is (not necessarily correct theoretically) the low end roll-off.

If TL is considered a very big sealed enclosure (infinite baffle) then the roll-off will start earlier at the midband, with a shallow slope gently roll off to a very low frequency. The energy required to reproduce this kind of "massive" low frequencies makes the driver lost its ability to reproduce low level dynamics. E=mc^2 (First law of thermodynamics)? (Hint: look at the cone movement)


Originally Posted by vikingshill (
do you know what diff it make to play with the stuffing ? or damping the port some,

Theoretically stuffing will change the imaginary box size. More stuffing means bigger size. It is more critical to accurate design when there is a port/opening in the enclosure. Stuffing is like tweaking the enclosure design small mistake. Damping the port, if you mean is partly "seal" the port, will make the stuffing less critical because it starts to behave more like a sealed enclosure. But it is still a big sealed enclosure with issue mentioned previously.

speakerman19422 20th May 2011 05:37 AM

Just looking at the damping material without knowing the plans it's to dense in the back of the cabinet. I would remove half of the wool and place it below the drivers in the bottom front of the enclosure and test.

Hsmeets 20th May 2011 02:42 PM

original post deleted, my stupidity as I thought you referred to the regular Thor design......

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