math help..
is not needed. You should choose a throat area at least equal in area as your driver if possible. The ratio between the throat area and mouth area is critical. Choose a single vent, by reducing the diameter if possible and maintain the throat area as close as possible to the area of the driver, (commonly referred as "Sd" in loudspeaker design formulas). The length of the horn must be some multiple of pi*D of the inside of the tube. That's it.
is not needed. You should choose a throat area at least equal in area as your driver if possible. The ratio between the throat area and mouth area is critical. Choose a single vent, by reducing the diameter if possible and maintain the throat area as close as possible to the area of the driver, (commonly referred as "Sd" in loudspeaker design formulas). The length of the horn must be some multiple of pi*D of the inside of the tube. That's it.
I all sounds so simple now, thanks!! My remaining question is at the heart of my confusion I think. Is the throat area the volume inside the tube minus whatever volume the spiral inside the tube displaces? To determine that area I use L x pi x r^2 then subtract the area of the spiral? Or is the throat area just the opening at the top of the spiral formed by the spiral{the somewhat rectangular opening} . The mouth is then the area from the throat of the horn to the end of the horn?
What it all looks like
Some pics of the finished stuff
Close-up
The cabs in their natural environment
I'm digging the "no visible vents yet can go right against a wall" thing
I've also caught extensive DIY bug, and my apartment is currently riddled with designer DIY circuits:
The lights are so low that not even IS can save it
A close look
Can you name all the circuits in there?
There's a DAC, a Heamphoe/Preamp, a power amp, and a SMPS crammed into that wodden box.
Some pics of the finished stuff
Close-up
The cabs in their natural environment
I'm digging the "no visible vents yet can go right against a wall" thing
I've also caught extensive DIY bug, and my apartment is currently riddled with designer DIY circuits:
The lights are so low that not even IS can save it
A close look
Can you name all the circuits in there?
There's a DAC, a Heamphoe/Preamp, a power amp, and a SMPS crammed into that wodden box.
Re: anymore pix, what about listening impressions?
I'm not so sure it's a port resonance anymore. I stuffed some fiberglass into the box (but not the tube) and the resonance is gone. Maybe cause by reflected high range waves?
These speakers are awsome, that's all I can say. These are among my first pairs of HiFi speakers so there's very little that I can compare them to. However I can say that they sound much better than my rommie's $4000 JVC component bookshelf system with overpowered subs!
Nanook said:
I'm not so sure it's a port resonance anymore. I stuffed some fiberglass into the box (but not the tube) and the resonance is gone. Maybe cause by reflected high range waves?
These speakers are awsome, that's all I can say. These are among my first pairs of HiFi speakers so there's very little that I can compare them to. However I can say that they sound much better than my rommie's $4000 JVC component bookshelf system with overpowered subs!
land of mapled honey?
maple sugar, ok,
golden honey...
mapled honey? Nova Scotia? maple sugar boiled down to molasses consistency..
the boxes need to be stuffed like a regular bass reflex, only the port should resonate at the correct frequency, Fs, and the horn "amplifies" the magnitude of the wave for greater output....
still, how do you like them, what can you compare them to.? Have tou listened to them as part of some sort of "reference" setup? (what do you listen to usually if not the PC?)
maple sugar, ok,
golden honey...
mapled honey? Nova Scotia? maple sugar boiled down to molasses consistency..
the boxes need to be stuffed like a regular bass reflex, only the port should resonate at the correct frequency, Fs, and the horn "amplifies" the magnitude of the wave for greater output....
still, how do you like them, what can you compare them to.? Have tou listened to them as part of some sort of "reference" setup? (what do you listen to usually if not the PC?)
That does it. I'm going to build some of these myself. I have the wood all ready for gluing the reference MLTL for the FE127 discussed in the long reference thread. Before gluing I'll make a changeable plate for the port. Then I can build the spirals and make it interchangeable with the port and see what the effects are.
If the port output of an MLTL is an improvement over normal BR and the spiral horn improves a BR, then adding the effect of spiral horn may do something extra special to the MLTL.
If the port output of an MLTL is an improvement over normal BR and the spiral horn improves a BR, then adding the effect of spiral horn may do something extra special to the MLTL.
Stocker said:
I'm going to start with the cab show in post #512 here.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=46934&perpage=10&pagenumber=52
That way we have a reference cab that some others have built.
For the spiral horn I'll construct one that has a throat the same size
as the port on the MLTL. I'll have to take another look at Takenaka's site before deciding on the other spiral dimensions.
A question I have about MLTL's is how does it behave without stuffing. I'm hoping it just become a BR. Then I can also do a direct comparison of BR to the spiral horn cab.
Well done
I'm hoping my reply will bump this thread up....I'nm sure there will be a few people looking for this thread now.
I had the chance to hear the finished speakers at the Northwest Audiofest this Saturday and was very impressed. The bass sounded relitively deep and very well controlled. I think everyone at the event was surprised by them.
Jason
I'm hoping my reply will bump this thread up....I'nm sure there will be a few people looking for this thread now.
I had the chance to hear the finished speakers at the Northwest Audiofest this Saturday and was very impressed. The bass sounded relitively deep and very well controlled. I think everyone at the event was surprised by them.
Jason
I was actually dying to get an impedence and response curve for these speakers. It's too bad I had to leave early for the RAW fest!
My ears (in my sad *** small room) lead me to beileve that the response is flat down to around 40hz, thanks to the smallish fs, but I would have to gain access to a good measuring rig and environment...
Does anyone know of a good place to measure the curves in the Vancouver area?
My ears (in my sad *** small room) lead me to beileve that the response is flat down to around 40hz, thanks to the smallish fs, but I would have to gain access to a good measuring rig and environment...
Does anyone know of a good place to measure the curves in the Vancouver area?
Hi eVITAERC,
Ported FR's will do that in a small room. My bass measurements showed a -6dB at 40Hz in my small living room. But remember the bass was pretty present in Al's smaller room. Then died completely in the big room, while yours were quite balanced still.
It's a mirage, indigenous of FR drivers in small rooms in ported enclosures methinks
eVITAERC said:
Ported FR's will do that in a small room. My bass measurements showed a -6dB at 40Hz in my small living room. But remember the bass was pretty present in Al's smaller room. Then died completely in the big room, while yours were quite balanced still.
It's a mirage, indigenous of FR drivers in small rooms in ported enclosures methinks
eVITAERC said:
I'd be very interested to see the results if you end up having an impedance curve done, just to see where the impedance dip, or "tuning frequency" is I am still trying to figure out exactly how this "spiral" works. My thoughts so far are:
-I can't see it being a horn, the mouth opening is much too small for it to be effective as a horn at low frequencies.
-I can't see it being a transmission line, the impedance curves shown on Masaaki Takenaka's site don't look like a TL's at all.
-The impedance curve I did find on Mr. Takenaka's site makes it appear as if the "spiral" is acting as a port. That said, I still can't figure out how there can be any real advantage over a standard ported box. If it wasn't for the fact that I have heard these in person you would have a tough time convincing me they work as well as they do.
Jason
A note to add to my previous post....
I emailed Martin King to ask if he had seen such an enclosure and if it could be modeled with his worksheets. Here is his reply......
"It is a very complex to build TL enclosure. My guess is that you could build a straight TL enclosure and produce close to the same quality sound. A TL will have a double humped impedance curve just like a bass reflex. As you add stuffing the first impedance peak will decrease and eventually blend into the curve reducing the impedance to a single peak. You can use any of the TL worksheets to model the enclosure if you edit the detailed input and adjust the number of sections and the geometry.
Hope that helps,
Martin"
It would be interesting to see if the same result could be obtained using a more traditional TL.
Jason
I emailed Martin King to ask if he had seen such an enclosure and if it could be modeled with his worksheets. Here is his reply......
"It is a very complex to build TL enclosure. My guess is that you could build a straight TL enclosure and produce close to the same quality sound. A TL will have a double humped impedance curve just like a bass reflex. As you add stuffing the first impedance peak will decrease and eventually blend into the curve reducing the impedance to a single peak. You can use any of the TL worksheets to model the enclosure if you edit the detailed input and adjust the number of sections and the geometry.
Hope that helps,
Martin"
It would be interesting to see if the same result could be obtained using a more traditional TL.
Jason
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