Is that possible to find out with hornresp?

Yep.

To be honest it would suprise me at all if the Kappa Pro 15LF wouldn't reach Xmax at just 600 Wrms in the Tempesthorn (now that I think about it, that goes for 300 Wrms aswell).

A speaker reaching Xmech can be heard if you're pretty close to the box. Hearing how it exceeds Xmax would probably need superhuman hearing (talking about folded basshorns off course).

Could it be thought that there is some kinda front chamber? Where does the first segment begin?

There is pretty much always a front chamber since the air in the cone can be listed as frontchamber.

It's sometimes pretty tricky to find were the horn starts and the frontchamber ends. In this case I would say that the horn starts in the centre in front of the driver (at the baffle not conus) and the frontchamber the space before that. But perhaps someone else thinks/knows different?

In first case you could just simulate as an exponential horn, with S1 being the area at the throat and S2 the mouth area. Dividing the horn in conical parts would give a less nice result in SPL-response tho and perhaps also in Xmax, but it would give an good idea anyway.

You could always mail Adire/Dan to ask for the specs as he used it. Come to think of it, do that before you start calculating. Previous experiences from myself would be that you can get easily a 10% marge in specs if you calculated roughly yourself.

but it's impossible to simulate the cabs with tempest parameters since adire publishes mainly Fs Vas Q, etc

Than how the heck did I end up with the Tempest as one of the drivers in Hornresp  ?

Ok tell you why:

If you doubleclick on the field were you put in the required T/S-parameters, you'll find that you can calculate RMS. CMS, BL and Mmd from other T/S-parameters, which you do have. Btw. You'll have to calculate in a specific order as you'll find out yourself anyhow.

For lenght draw a middle line in the horn. Actual path would probably be slightly longer since bending increases hornlenght. Remember mail Dan first (say you use Hornresp), don't know if someone replies but it will save lots of time if so.

VTC is Volume Throat Chamber (it's in cubic cm, so 1000 for 1 ltr), ATC is the Area at the beginning of the Throat Chamber, make it Sd in this case (my quick guess).

Leave FR and TAL blank (won't matter too much). Make sure to fill in LRC (make it 20) or you'll simulated something entirely different.

1 cab at 1,0 pi would be the same as 2 cabs in 2,0 pi (just for response not power) 1,0 pi is also 1 cab on the floor and against a wall. Ussually it gets 2 Hz to 5 Hz of lower f3.

Btw. Found all this out in about a month, without help from outside, just simulating, trying and reading Help-function at least 25 times

If I can do it why can't you ...... OK OK I pretty much s*ck at electronics.

For now...

Good luck

Supposedly my simulations were wrong, but i didn't reach Xmech with 100Vrms (about 1250W@8Ohms). Poorest/highest result was 14mm diaphragm displacement, which would be still less than Xmech (28mm total from 34mm Xmech)

You're talking about Xmech, I'm talking about Xmax.

Normally you use a speaker within it's Xmax, sound is best that way and you have plenty headroom as safety. Beyond the Xmax less of the voicecoil is in less of the magnetic gap, so the further the speaker goes beyond Xmax the more it will loose control.

Hornresp simulates as if the speaker has full control over the cone in those 14 mm. Instead beyond Xmax (so 5,5 mm orso), the speaker will have less than 100% control, perhaps only 30% at 10 mm, who know's. Well we don't, so we simulate only with the facts we do know: Xmax.

Most horns I simulated reach Xmax at just 200-300 Wrm. Theoretically that is.

In practice music isn't the sinewave Hornresp is using for the simulation. Depending on the kind of music and lowcut, the actual powerhandling will be about 1 - 2 times as high.

The higher the lowcut is placed the higher the powerhandling. Some sinebass songs (d&B) will have close to zero tolerance on the simulated powerhandling. Normal popmusic will give a powerhandling that's about 2 times as high as the theoretical powerhandling. For tekno/techno/gabba I use about 1.4 -1.6

Cheers

I was after Xmech since i wanted to see how easily i can accidentally break them if i wanted to try them with more power..

As I tried to explain it's useless to simulated with Xmech. If the Xmax would be 7.5 mm for instance and Xmech would be 15 mm (one-way). If the speaker would still behave linear beyond Xmax it would take about 4 times more power to reach Xmech, but since the speaker looses control above Xmax it could well be that Xmech is reached with only the double power (or 6 times for that matter).

You just don't have enough facts to base any serious thoughts on that simulation.

I would say Xmech is a marketing-related invention. Excellent material for a manufacturer to put in big letters in an advertisement, but only something you can keep in the back of your mind while designing, not actually work with it.

(Taken the fact into account that true excursion won't be even THAT much due to VC going away from magnetic gap and power compression)

Perhaps I'm misreading this, but in my vision it looks like it would be exactly the other way around. If the VC moves out of the gap it will need less power for excursion.

Powercompression wouldn't save you from overexcursion (it did totally the opposite in my experiences).

@40Hz it was about 11-12mm. If i hi pass them somewhere around 40Hz I should be completely safe with amps having such power/cab

I hope that by now you will take the frequency where the Xmax is reached as your new lowcut frequency. Play it save at first, if you're unhappy with the results you can always look up to the limits. Instead of taking risks by trusting on a best case scenario straight away.

and the result was even better!

If you would try it again at a later time, chances are that you would even make more progress. Don't go over one night simulating. Let it rest for a few days and look again, changing every hornparameter and compare with the previous result with the comparisation-function.

Response isn't the smoothest available, but since i use them below 100Hz (currently -3dB at 90Hz and 24dB/oct slope), it's totally usable.

Alright!

Cheers

Xmech can indeed very usefull, eg. the Ciare 12 you use has an Xmech very close to its Xmax.

Cheers

Too bad I'm not a guru, so my motivation in this case is rather based on thoughts as well. Perhaps someone else could help us out?

See i've always thought that when the voice coil goes farther from magnetic gap the magnetic flux would be smaller thus requiring more current in coil to keep the force equal

Agree.

Thus the cone excursion would be smaller and smaller flattening the obtained pressure maximum until the Xmech is reached where the driver bottoms mechanically

Not sure that I understand this correctly (at a certain point my lack of English blurs my mind and keeps it from understanding even when read 4 times over ).

But did you conclude that the VC is already moving with certain force/speed (gets kinda launched) and at the point where it normally would be forced to turn back the motor has not enough grip on the VC anymore to effectivly do so

Still biggest problem would be that if the flux lowers (and so does the BL and No) the speaker parameters change, while Hornresp asumes that it will stay the same (as would be the case in Xmax). We even don't know how fast or slow BL decreases.

So there really would be no use in using the Xmech into any of your simulations/calculations.

It's still a bit fuzzy what should be interpreted as the front chamber volume and where the horn really starts.

Personally I use the smallest area as the border between chamber and horn.

I had comma in wrong place on mechanical suspension loss value

I had the same problem the first 2 days I used Hornresp

Cheers

Xmech is probably extremely difficult to achieve anyway

Well, I've some practical experiences telling otherwise, so from there my concern. Most where with tops, but it was supprisingly easy to achieve (than again DJ's have special powers when it comes to that)

I actually know someone who sets up his w-bin system like that: Applying more power till he hears ticking and then back-off a bit.

@Hiphei: Can you post a screenshot?

I know that 18Sound's 18LW1400 has problems long-term with the surround

What kind of problems? I happen to be an owner and I'm designing a horn for it, so any info would be welcome.

Cheers

Double what?

Why do you simulated in 1,0 pi? Unless you will always put it against a wall (or use 2 in a stack) it will give a false indication. One cab in halfspace would be 2,0 pi.

In practice I would apply a lowcut at 50 Hz (or higher) if you tend to put 600 W on each (in theory it always looks wurse). And if I was gonna use a 50 Hz lowcut anyway, I would optimize the design to get a little bit more flat and higher output in the 50 Hz+ area at the price of gain at <50 Hz.

This would mean you could make em shorter and thus smaller. It would also get a higher powerhandling and a flatter reponse. But off course that's also personal favour/taste

Btw. L45 should also be conical, not exponential.

Hi mobiele eenheid: I meant the double 18" horn that was being mentioned on J&H a while back

No, not that one. I would like to make a horn that can be used by every beginning and mediumsized drive-in's for up to (a serious) 200 people indoors. For most drive-in's a f6 of 40 Hz would be sufficient (it's also ment for just one a side). I'm working on a corresponding top as well.

It will use 2 modules like Walt's M-horn (tho slightly improved me thinks ).

Do you also respond on the forum or do you only read it?

edit: I did put up a thread in psw sub forum just in case someone over there was familiar with tempesthorn..

I noticed  I'm around..

You should try diyaudio.com instead. A lot of Adire fans hanging around there (Dan Wiggins and Tom Danley as well )

Which version of Hornresp are you using? I'm also getting differents results with 7.2 compared to 8.

Remember Hornresp (and most other simulating prog's as well) simulate with a 3 dB-sine. Normal bass in music is more like 6 dB (dynamics). So 300 W simulated can get around 600 W in real-life.

Personally I wouldn't mind about that anyway, since mnost horns get you 3 dB more output with half the power (compared to BR), so it isn't really limiting your SPL.

Any idea what has been changed/improved  on Hornresp 8 ?

With a bit of luck, my design results improve because Hornresp improves.

Timber_bg: Jou Nederlands is baie goed. Nie veel fout nie. (enkel schrijven) Beter dan mijn Afrikaans.

Sorry guys: just to say that Afrikaans is quite close to Dutch.

Simplest way to decrease a volume is to place a board on the correct place (see 1850/186 horn).

Cheers

How easy it is depends on the opening/location of the backdoor, can you fit it in in one piece?

Otherwise you can use multiple pieces (to form one piece) to do the job. It would even strenghten the construction in that way.

The tip of the 'A' went through my rib and i got stuck on the ladders since my feet didn't reach the floor

Sounds painfull

At least now i have time to play with hornresp..

There should be a smiley there instead

Good luck!