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Old 6th November 2008, 04:40 AM   #31
FlipC is offline FlipC  United States
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Join Date: Aug 2008
I have played with the "Input Power"
and Xmax setting but dont understand the Xmax one. Does this disregard the Input Power? Cause it still says 100 watts 15 mm Xmax... (on a my particular driver)
Shouldn't it be so you set max Xmax and it figures amount of power it would take to reach that and the given SPL graph to boot...

And what do you mean clipping?
Not like I see a clip indicator ?Something else I am missing...?

I assume HR
can not model multiple TH speakers like it can other horns?
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Old 6th November 2008, 01:48 PM   #32
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Location: Fort Collins Colorado
Quote:
Originally posted by FlipC
I have played with the "Input Power"
and Xmax setting but dont understand the Xmax one. Does this disregard the Input Power? Cause it still says 100 watts 15 mm Xmax... (on a my particular driver)
Shouldn't it be so you set max Xmax and it figures amount of power it would take to reach that and the given SPL graph to boot...

And what do you mean clipping?
Not like I see a clip indicator ?Something else I am missing...?

I assume HR
can not model multiple TH speakers like it can other horns?
Xmax is the xmax rating of the speaker not the maximum excursion before damage rating. The 3015 xmax is 9.0 and If I remember correctly the maximum excursion before damage is 15.
The speaker runs out of gas at 9, it disentegrates at 15....I'e.
physically damaged beyond repair in less than the time it takes for one kick drum beat. You can hit xmax of 9 with a 3015lf at 40 hz with only 45 watts. Even less at 30hz!!!!!

Clipping.
Look at the top of the waveforms (peaks) as you raise the level.
You will see probably the lowest frequency one start to flatten out or become distorted and deformed. That's clipping.
You can not eliminate it completly but you can balance it.
Horn resp has been damn good. While the levels may be different depending on your test procedure, the cabinets built tend to respond as expected. Using the max spl otpion along with displacement, the cabs I build have all behaved as predicted.
Don't go by the manufacturers max power rating only. The compression factor of the speaker blasting away will throw off your horn adjustments. I only use that rating to see if my maximum pushed to hell level is fairly balanced.
The last box peaked at 128db at 45hz and I think 80hz at the same time in hornresp. The actual box peaked at 126db at 45 and 80 as expected at about the same time.

Look at your displacement as well, you may be running out of xmax at lower frequencies and will not be able to get any more out of it down there. So you work with the next higher freq peak.
The box will roll off as it gets louder and the driver runs out of gas.
Hope that helps
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Old 6th November 2008, 06:13 PM   #33
FlipC is offline FlipC  United States
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So I take it that setting Xmax ignores Power Input ?
IE when it says 100 watts an X amount of Xmax . It is not considering the 100 watts just the XmaxI set?


Ok so you are using the spikes as clips.
Gotcha.
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Old 6th November 2008, 06:52 PM   #34
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Location: Rotterdam, NL
Quote:
A couple of cm makes a BIG difference in a PA type cabinet
Where and in what way?

Regards Johan
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Old 6th November 2008, 09:54 PM   #35
FlipC is offline FlipC  United States
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Use the TH Wizard.
Do small adjustments here and there and you will see. Some sections make bigger differences than others.
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Old 6th November 2008, 10:38 PM   #36
GM is offline GM  United States
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Quote:
Originally posted by FlipC

How can one model more than a single TH cabinet in HR?
Input the summed specs of however many drivers is required, design TH, then divide all the areas by however many drivers there are to find the areas for a single driver TH.

GM
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Old 6th November 2008, 11:11 PM   #37
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Location: Fort Collins Colorado
Quote:
Originally posted by FlipC
So I take it that setting Xmax ignores Power Input ?
IE when it says 100 watts an X amount of Xmax . It is not considering the 100 watts just the XmaxI set?


Ok so you are using the spikes as clips.
Gotcha.
Yes Xmax ignores power input but it tells the program where the woofer will reach xmax based on the other driver parameters.
You can put 2 hundred watts into a driver at 120hz and barely reach xmax, but the same driver may hit xmax at 40 with only 65 watts. One example is the jbl2225. It's so stiff that 40 hz wont really hurt it too easily. It won't make much 40hz, but you'll have a harder time blowing it than a 3015lf or a very loose home woofer. The point where the JBL will clip at 40hz will be at a higher input level than the 3015 but with a lower output level.
Once again...it's all a balancing act, give a little here get a little there till you reach the best compromise for what you have.


Spikes as clips
Not the spikes themselves, the point where the tips of the spikes flatten out is clipping. When a nice curve turns into a flat line at its peak or upper limit, that's clipping.
A picture is worth a thousand words but I cant get to my server from here.

GM thanks for the tip.
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Old 6th November 2008, 11:21 PM   #38
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Join Date: Jun 2005
Location: Fort Collins Colorado
Quote:
Originally posted by Rademakers
Where and in what way?

Regards Johan

Quote:
Originally posted by FlipC
Use the TH Wizard.
Do small adjustments here and there and you will see. Some sections make bigger differences than others.
You may find that adjusting something doesn't seem to make much difference..... after you tweak a few things that do, suddenly the first adjustment you were making seems to actually
do something. That's because somewhere down the line something else is effecting what you were adjusting such that
any changes would seem to have no effect.

The easiest way to explain it (I think sometimes.....)
It's like water in a pipe, you can turn the knob all you want but only so much will come out of the faucet. You can install a bigger pipe but you may still only get the same amount of water because the main valve isn't open all the way..... or you are still using the same faucet which will only allow a certain amount of water to flow regardless of how big a pipe feeds it. The same theory applies here. Luckilly we don't have to deal with gravity too much as well
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Old 7th November 2008, 07:01 PM   #39
FlipC is offline FlipC  United States
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So I have built 3 TH's so far.
The first was a test box for proof of concept.Even being built out of OSB it still sounded good. So I built 2 more to spec out of MDF.
They run 50-200 Hz with a 24db crossover. I lap over the upper bass with 15" mids at 150 Hz to even out some dips. I also bump 50 Hz just a tad to get it flatter. I have used these 2 subs at an event and ran them full bore for almost 5 hours. I checked them before break down and the drivers were luke warm to touch. Yet another reason why I like the TH design. Long as no drunk throws a beer into it!

Anyway. I have been wanting to build some "sub sonic" tapped horns to fill the lower end.
These really only have to fill below 60 Hz. I have been playing around and have come up with some possibilities but was having issues with excursion in the upper low end.
So I just fiddled with using 4 cabinets
(as long as I understood GM correctly and just multiplied ALL my speakers' specs by 4) and it looks promising. Also using MAX spl which is what I am going for so used 80volts for 400 watts at 4 ohm. (ish) Just over 580 Lt per cab. Not small but doable. Specially rectangular shape for center fill with mouths together. (alla DTS style)

So lets see:
Click the image to open in full size.

So how far am I off things?
(I know it would take some EQing to get it this flat at this level but I can do that.)

Also - how does stuffing effect
TH's? Will it effectively make a segment length "longer" to the wave ? Is there a way to model this in HR?
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Old 8th November 2008, 05:27 AM   #40
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Location: Fort Collins Colorado
O.K. I'm done. Out of time, money and my lady's patience..

I'll have two offerings to post in a few days as soon as I have time to remeasure and draw them out, and post them on the server. I'm hoping someone more masterfull with compression and path smothing can tweak them before I actually build the real 6.

They are the PATH15 and the HTH15. Perfect, NO, usable, YES, practical, DEFINITELY, Portable, most certainly. Loud?......... every musician in the neighborhood wants to hire me after rattling thier houses with only one and then finding out I'm building 6.

The scripts I posted earlier are basically correct.
Both boxes have a 39x31 side profile. Wheels on the back bottom ramp, and the top back ramp will house built in handles.
The Path15 needed some tweaking on s1-s2 and a ramp added to get the box geometry to work. The box is 24" internal width.

The HTH15 is actually the more interesting of the two as the woofer cone fires down into the mouth. That puts the woofer in a protective and voicable chamber. The articulation is really sweet. It's a 21 inch internal width. To make it wider you would have to make it shorter and deeper which would allow a little more horn for better gut wrenching bass. The secret to it is in the woofer's chamber. I discovered that you need to make it as small as possible to get the cabinet tight. Difficult to do without molding a custom filler out of expanding high density foam.
This box should be played with!! If we can chamber it right and get the chambers port compression optimized for the horn it may become the best diy utility pa box. The absence of a 80-100 dollar grille ordered from LA to protect the driver makes it VERY attractive. The prototype also seems to behave pretty well to driver swaps. My Jbls sounded pretty nice in it too.
The HTH can be crossed over much higher than the PATH and will work well with weaker tops. Try 20400 as the chamber volume to start instead of the 30400? You'll see what I mean.
Smaller the chamber the better it gets. A squatter version doesn't bother me as I'd be stacking them sideways anyway.

I ran my "finals" with tops. The Path is a SUB and it will make you sick. The mid bass articulation is not good enough to meet weak tops. Probably because of the inverted cone and the physical frame of the woofer in the direct path.
The HTH in 21" sounds pretty damn good but lacks the "Brown Note" cabable 40hz or so low end. At least for now. Once again very articulate and clear. It runs about the same level as the PATH. I think they each have a specific use.
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