How much better can i make this TH

[FlipC]

I still want someone to chime in about
the possible cancellation from the phase differences due to the distance differences.
In all of the Danley dual setups
the 2 drivers are at an angle to each other and then the quad and 8x setups are push pull.
Anyone?

On a side note.
There are 2 phenomenon's I have scene is TH's. A contradiction if you will.
One is that you can get decently high SPL from a small enclosure with less power. Or you can get allot more power handling before Xmax.
I have 2 designs that can take well over 300v (4ohm) and still not be at Xmax. To bad the driver cant handle the 23K watts. (anyone got a 21" driver that can?)

So retest your subs
outside and turn them up unto you here them clap a bit. Turn them down a bit from there. Retest SPL. If you can measure voltage (how are you measuring?) it will give you a better understanding of how well the layout/design does.

Cause when are you ever going to listen to them with just a single watt?

[BP1Fanatic]

Originally Posted by FlipC

I have 2 designs that can take well over 300v (4ohm) and still not be at Xmax. To bad the driver cant handle the 23K watts. (anyone got a 21" driver that can?)

Are you saying that just because you design a horn where the speaker can handle X number of times it's rated power, you can't feed the speaker the wattage the enclosure can handle? Example: the MCM 55-2421 is rated at 120w RMS. If I designed a horn where the MCM can stay under 8mm Xmax @ 1,200w RMS, I can't actually give the 55-2421 that amount of power?

[badman]

Originally Posted by BP1Fanatic

Are you saying that just because you design a horn where the speaker can handle X number of times it's rated power, you can't feed the speaker the wattage the enclosure can handle? Example: the MCM 55-2421 is rated at 120w RMS. If I designed a horn where the MCM can stay under 8mm Xmax @ 1,200w RMS, I can't actually give the 55-2421 that amount of power?

That's right. There are 2 types of output limits in a driver- thermal and excursion. Most of that 1200W is converted to heat in the voice coil, so, imagine the heating element of a hair dryer as a loudspeaker voice coil.

Doesn't result in such a good ending, does it?

[FlipC]

NO!

Just that a TH acts like band pass sometimes.
Though with a TH design as such you can probably run the driver over the rated max input level. Having the magnet and coil assembly facing out at the mouth means you have great heat dissipation. I have ran mine at full throttle for over 5 hours straight and they weren't hot. Warm yes but not like a driver in a FLH.

I was just stating there seems to be 2 avenues you can go
with a TH design.

[littlemike]

Originally Posted by BP1Fanatic

Are you saying that just because you design a horn where the speaker can handle X number of times it's rated power, you can't feed the speaker the wattage the enclosure can handle? Example: the MCM 55-2421 is rated at 120w RMS. If I designed a horn where the MCM can stay under 8mm Xmax @ 1,200w RMS, I can't actually give the 55-2421 that amount of power?

No, you can't. The magic smoke comes out. I learned this the hard way, and I have the pictures of the aftermath somewhere.

The voice coil can not dissipate the heat generated by pushing high currents and voltages through it. The heat melts the coil former, which distorts and causes the cone to stop moving. Once the motion of the cone stops pumping air through the gap, things really warm up and the glue and varnish smokes. If you cut power at this point, you'll still have continuity through the coil, but it is more of a copper slinky. I stopped here, as it was pretty obvious that something broke (the big noise stopped). Had I kept going, I could have killed my amp or lit something on fire.

[FlipC]

Sorry but I am laughing.
Cause I like to take burnt drivers and feed them direct current and watch what happens.

I have never caught a speaker on fire inside
a cabinet. Though I have burnt out drivers. Only due to either a DC surge. (damn generator) or the access panel coming loose. (happened more than once)

Hmm,
My mind starts thinking about the years I spent overclocking CPU's. Anyone know if there has ever been a super cooled speaker? IE other than air?

You get rid of the heat
you can push more power. Normally though you are talking about a sealed enclosure. So it is just getting hotter and hotter. hence the cooling plates on Lab Subs and some other FLHs. A reflex box has some cooling but the TH has a big advantage here. To a point it comes down the cone and its parts not being able to withstand the pressure.
Which I have also done in testing band passes.

[bko69]

I made a second box. I added an extra fold in the design. The throat area is a constant 1" up to the next fold. I messed up and cut the driver board to short. you can see in the first photo how i patched it up to make it work.




Here is the cut list

9.5" x 19.5" - 5 degree angle on one end
9.5" x 3.5"
9.5" x 19.75"
9.5" x 16"
9.5" x 13.25"
9.5" x 10"
9.5" x 13.75" - 5 degree angle on one end
9.5" x 24"
9.5" x 24"
9.5" x 23"
24" x 24"
24" x 24"

I live in oregon and it has been raining here, so i can't go out side to do measurements. These were done inside at 2.83v / 1 meter:

30hz 28
35hz 44
40hz 63
45hz 71
50hz 77
55hz 79
60hz 72
65hz 78
70hz 82
75hz 80
80hz 81
85hz 82
90hz 82


To me the second box sounds better. By the numbers there is a little more low end and the upper end has evened out. I have not tried corner loading but guess that the numbers will be higher.

I'm an armature here and really have no idea what i'm doing. Is it over kill to have 2 drivers in this box? Is this design looking good or bad? I'm really looking for something that is small and easy to lug around. This design is small but if it is not going to preform well then i need to look at another design.


bob

[davygrvy]

You might consider 1/2" ply with some internal bracing to shave some weight regarding the lugging factor. What performance are you looking for? DJ use or a PA for a rock&roll band? And how many of these cabs do you intend to place on your pile?

[davygrvy]

Just 'cause the magnet structure isn't hot, means nothing about the coil temp itself and how well (or not well) it can dissipate that quickly to the surrounding steel.

I was testing some tweeters about a year ago at my job and you wouldn't believe how fast coil temp can spike on peaks. Same concept applies larger coils of woofers, but there is more mass so things don't go poof as quick.

[BP1Fanatic]

Originally Posted by FlipC

NO!

Just that a TH acts like band pass sometimes.
Though with a TH design as such you can probably run the driver over the rated max input level. Having the magnet and coil assembly facing out at the mouth means you have great heat dissipation. I have ran mine at full throttle for over 5 hours straight and they weren't hot. Warm yes but not like a driver in a FLH.

I was just stating there seems to be 2 avenues you can go
with a TH design.

What if the magnet & coil assembly is mounted in the throat of a FLH? Shouldn't the same heat dissipation apply?