Collaborative Tapped horn project

GM: Thanks for the links. I'll burn them to a CD and them out.

I've also got the lord of the rings films, but I haven't watched them yet at home... So now I have an excuse. :)

I forgot to ask before, what crossover settings are you guys using? Here's what hornresp predicts for the TH I've built:
An externally hosted image should be here but it was not working when we last tested it.


So I'm using a LR48 HPF set at 30Hz along with a LR48 LPF set at 100Hz, and it sounds good. I really need hook my laptop up to my DCX and experiment with different slops and XO points when I get time...
 
just a guy said:
Be very careful the volume when watching those movies or something will get broken. Most of those movies have very significant output more than 2 octaves below the tuning of the box.
Right now I've got a high pass filter at 30Hz, set to 48DB/oct (LR) which should lower the risk of anything breaking...

I did hear some rattling today when watching Finding Nemo, it could either be a door in my house or one of the braces in the box... It did sound like it was coming from the box tho. :(

I'll have to try it outside at some point to be sure.
 
so i take it im good to go, basicly the same as mikehunts, just as i may as well make it the hight of my room it get a tiny bit more at the low end,

2 questions will 6.2mm xmax bottom out at 20hz?

and any idea's about my idea of adding some damping, i have seen this done in transmission lines to slow the sound waves making the line appear longer, this in turn makes it tuned lower

and is my design, (same as mikehunts but 40cm longer) correct?

then i can get this thing underway, i have a amp that can do 180w bridged mono, im guessing this will suffice

and last question, is this thread ever going to die? its huge :D
 
Questions Post #1664

Naudio: To Post #1664,
question 1 - there has been no consensus as to xmax as it relates to the tapped horn, it may be wise to consider going with the Hornresp values even though some suggest to at least double that value;
question 2 - damping in the sense of the transmission line is most likely neither necessary nor desirable for a tapped horn, lining of the horn walls - as in the Danley DTS20 - will probably improve the high frequency performance;
question 3 - looking at Hornresp models, there is a lot of leeway in the L23 dimension, when you go longer you loose some output and gain some low frequency extension;
question 4 - I hope not, I'm still waiting for iand to discover (and hopefully share) the answer to your first question.

MikeHunt79: Thanks for the pictures and the performance description.:)
 
xxls vs 4012

Sabbelbacke said:
maybe the xxls has a lower impedance? try adjusting the inpult voltage so it matches 1W in both cases (double click on the input field, enter the Re value). You get a better comparison this way.
If you want to know how much is acheivable in maximum, use the "max SPL" feature in the SPL chart.
Sabbelbacke is right, the peerless has 4 ohm impedance while Eminance has 8 ohm impedance from what I remember...

Both drivers are a similar cost in the UK it seems (around £150), I used the Magnum 12HO as I already have them sitting around as I got a good deal on them and I was originally going for the front loaded horn option.

If your amp works better with an 8 ohm load, then I'd plump for the Eminence driver.

The Peerless has higher xmax, while the Eminence has better power handling, so it also depends on your usage. I'm sure the Eminence would be better at high power for a long time (especially if you plan to use this outdoors) as it's designed for PA use.

That's not to say the Peerless will be not do high SPL, in fact if you are indoors, I'm sure it will still provide more than enough SPL, in fact it will probably provide more SPL than the Eminence due to the higher xmax so there's not much to choose between them IMO.

Which ever option you go for, as long as you do a good job on the enclosure, you will have more than enough SPL! :devilr:
 
the eminence i am about to buy has a 6.2mm xmax

according to horn response the cone moves 0.8mm with what im assuming is 1w this is 107db/25hz (in corner 0.5 x pi)

now how much power would i need before the driver reaches its xmax and what is the theoretical output

for example does the xmax double when u turn up the amp by +3db?

how do i calculate this?
 
Any hope for this design. I have a vintage university C-15w DVC woofer sitting around. I believe it was originally used in the University Classic bass horn section.

Simulating using hornresp, using T/S parameters I measured a while ago, there might be definite hope for the higher Qts / voice coil alignment (first sim). Let me know if I've goofed up converting the input T/S parameters or the sim. Not sure about the xmax , this has am old-style pleated surround.

If this sim looks decent, I'll build it later this summer. Seems relatively small.

An externally hosted image should be here but it was not working when we last tested it.

Code:
VC parallel

Thiele-Small parameters:

Fs  = 75.28 Hz
Re  = 2.20 ohms[dc]
Le  = 1385.95 uH
L2  = 614.39 uH
R2  = 13.51 ohms
Qt  = 0.42
Qes = 0.47
Qms = 4.13
Mms = 45.27 grams
Rms = 5.190255 kg/s
Cms = 0.000099 m/N
Vas = 101.43 liters
Sd= 855.30 cm^2
Bl  = 10.064444 Tm
ETA = 8.94 %
Lp(2.83V/1m) = 107.23 dB

Added Mass Method:
Added mass = 10.00 grams
Diameter= 33.00 cm

VC series

Thiele-Small parameters:

Fs  = 74.20 Hz
Re  = 6.00 ohms[dc]
Le  = 5625.62 uH
L2  = 2860.99 uH
R2  = 54.56 ohms
Qt  = 0.29
Qes = 0.31
Qms = 4.03        
Mms = 63.16 grams
Rms = 7.313565 kg/s
Cms = 0.000073 m/N
Vas = 74.83 liters
Sd= 855.30 cm^2
Bl  = 23.997259 Tm
ETA = 9.58 %
Lp(2.83V/1m) = 103.17 dB

Added Mass Method:
Added mass = 10.00 grams
Diameter= 33.00 cm
 
i have ordered the eminence, it just looks like the best option in my opinion so don't say anything to upset me, lol

i have also designed a end expansion of 50cm that can optionally attached for flat to 22hz, can add this after if it is needed

thanks for all the help in the design phase, will post up pictures of construction in a few days
 
Naudio said:
how do i calculate this?
Hornresp can calculate this for you...
When on the "SPL Response" screen, go to Tools, then "Maximum SPL"

Then simply put in the xmax and wattage. Bear in mind hornresp seems to predict more cone travel than is experienced in reality...

Try 10mm and 15mm xmax for the 4012, to get a ballpark figure. Also, there isn't much point in feeding the Eminence more than 400W rms due to power compression... I'm sure at 400W tho half your street will be able to hear the bass. :devilr:
 
zobsky said:
Any hope for this design. I have a vintage university C-15w DVC woofer sitting around. I believe it was originally used in the University Classic bass horn section.

Yes it was.

Hard to say since the specs are seriously suspect. I mean VCs in parallel Vs in series will be half or 2x what the open coil measures and Qes, Qms, Qts, Vas should measure the same within a tiny tolerance, so something's amiss.

GM
 
Naudio said:
the eminence i am about to buy has a 6.2mm xmax

according to horn response the cone moves 0.8mm with what im assuming is 1w this is 107db/25hz (in corner 0.5 x pi)

now how much power would i need before the driver reaches its xmax and what is the theoretical output

for example does the xmax double when u turn up the amp by +3db?

how do i calculate this?
double the travel for double the voltage input, if the speaker is still in it's linear range.
Double the voltage is 4times the power (+6dB).
0.8mm, 1W
1.6mm, 4W, +6dB
3.2mm, 16W, +12dB
6.4mm, 64W, +18dB

Change the voltage in the input field and you'll see the Xmax and dB effect.