Collaborative Tapped horn project

[mightym]

Try this one

[HornsKeith]

Originally posted by Josh Ricci
I figured as much. I'd be happy If I could get a relative useful range up to 60-80hz. I don't know if it's possible when getting extension down in the 20hz range or lower. I'm basically looking for the tremendous low end you mentioned.

Hi Josh. I tried a few combinations with HornResp yesterday, and mine look somewhat similar to what others have posted. I kept the compression ratio at 3:1 or less to hopefully make it safer. Not super smooth, but within a few dB for not having to crank down the areas any more.

1W response:



Params:



Here's that "tremendous response" we were discussing. Assuming nothing falls apart (the cone, the box, your house) of course.

Standard half space:



In a corner (eighth space)- a theoretical 135+ dB from 15 Hz up:




You should build it so we can follow and see if it actually does that, heh. Maybe check with TC Sounds first and see if they know how strong the cone is and what kind of compression ratio they think it could take at full excursion.

I'm still kicking myself over the GTG and things I should've done. Why I didn't get a close mic in the horn mouth of the TH50 and THspud I just can't reconcile. It would've taken all of 1min and I just plain old didn't think of it until the next day. The responses that were posted/ taken were 3 foot away with the mic on the floor so there is quite a bit of room influence. What I do have is numerous close mics of the sealed LMS and XXX drivers and their responses measured the same way in the same room as the TH's, so I can do a bit of extrapolation there.

Yep, that's hindsight for ya. In looking through your GTG REW graphs, I assumed the peaks that were common to all the subs were probably room induced (such as the 70 Hz peak). The 80+ Hz peaks and dips to the TH50 were unique and also quite similar to some of the HornResp predictions for slightly larger MTX horns (20 Hz TH). Example:



Regards,
Keith

[tb46]

When entering the parameters for the LMS 5400 18 into Hornresp it calculated values are similar to, but slightly different from the values in Post #3311.

For Josh_Ricci: Are your LMS 5400 18 parameters measured?

For HornsKeith: Your parameters differ a bit from the ones Josh Ricci posted in Post #3311/#3316. Are these parameters measured?

Regards,

[HornsKeith]

Originally posted by tb46
For HornsKeith: Your parameters differ a bit from the ones Josh Ricci posted in Post #3311/#3316. Are these parameters measured?

Regards,

Oops, no. That was me fat-fingering one of the driver parameters. I'll go back and fix my graphs/charts above.

Keith

[tb46]

Hi Josh Ricci, here is an example for the CSS SDX 15 in a four section Hornresp model:

Regards,

[Josh Ricci]

Originally posted by HornsKeith


Hi Josh. I tried a few combinations with HornResp yesterday, and mine look somewhat similar to what others have posted. I kept the compression ratio at 3:1 or less to hopefully make it safer. Not super smooth, but within a few dB for not having to crank down the areas any more.

1W response:



Params:



Here's that "tremendous response" we were discussing. Assuming nothing falls apart (the cone, the box, your house) of course.

Standard half space:



In a corner (eighth space)- a theoretical 135+ dB from 15 Hz up:




You should build it so we can follow and see if it actually does that, heh. Maybe check with TC Sounds first and see if they know how strong the cone is and what kind of compression ratio they think it could take at full excursion.




Yep, that's hindsight for ya. In looking through your GTG REW graphs, I assumed the peaks that were common to all the subs were probably room induced (such as the 70 Hz peak). The 80+ Hz peaks and dips to the TH50 were unique and also quite similar to some of the HornResp predictions for slightly larger MTX horns (20 Hz TH). Example:



Regards,
Keith

Thanks. Yep the GTG measurements all have a big 70hz and 45hz peak from the room plus a few other issues. The TH's seemed to exaggerate this a bit more and had some peaks higher in the pass band. I will try to give some TH design a try this summer. Possibly with the LMS 18 or the SDX.The models that have been posted look decent. I won't have time to play with them until later, but the output potential looks nice. I noticed that the graph posted for the MTX9500 looks really good especially the sensitivity. Is that for 1/2 space?

Originally posted by tb46
When entering the parameters for the LMS 5400 18 into Hornresp it calculated values are similar to, but slightly different from the values in Post #3311.

For Josh_Ricci: Are your LMS 5400 18 parameters measured?

For HornsKeith: Your parameters differ a bit from the ones Josh Ricci posted in Post #3311/#3316. Are these parameters measured?

Regards,

They are Praxis measurements, not of my particular driver, but TC is usually very close. I also have a WT3. The BL, MMS, RE, SD, LE is all spot on. The xmax and xmech are real figures.

[fb]

P.Audio FL-12LF SPECS

Originally posted by fb



P.Audio offered to sell me some direct from Thailand if the Aus distributor didn't have any... but I'm a fair way off from purchasing so didn't enquire as to price.


I'm also concerned as to accuracy of T/S specs.....



Alternatively, the B&C 12TBX100 performs similarly in same cab, though is pushing the displacement/xmax issue a little harder.

I emailed P.Audio to ask them the Xmech of the FL-12LF - their response:

X mechanical = 10.5 mm
X max = 8 mm
Hvc = 26 mm
Hag = 10 mm

Surely that's way too close for comfort? My sim pushes it to around 9mm



I'm still waiting for B&C to reply re. 12TBX100's Xmech - Faital Pro 12HP1020 is 16mm.

[HornsKeith]

Originally posted by Josh Ricci
I noticed that the graph posted for the MTX9500 looks really good especially the sensitivity. Is that for 1/2 space?

Yes, half space / 2.83V. The TH params are just a variant of what Bill Cowan posted in #699. The only unknown for me was the driver Le, which I couldn't find listed anywhere. I just dummied in 3 mH for modeling. Hopefully it's not too much higher than that, which would make the response much less smooth.

Regards,
Keith

[Josh Ricci]

How do these look? One is 600L and the other is 900L. I think the 600L looks decent if it's do able, but I'm a bit concerned with the first major spike that always seems to be present in the pass band. How bad is that in actuality? I can go to a 60-80hz steep xover but I don't think that will be enough. I guess I could notch filter it out.

[Don Snyder]

As far as I know, the longest tapped horn built to date is Chris's Lab12.
Chris built 2, I built 1, and Tone P just needs to put on
the last panel to complete his. The acoustic length is just short of 19 feet.

Josh: are you seriously thinking about building this 24 foot
monster? If driven hard, it could cause structural failure of your house.

If you take your horn outside to test (2Pi), that peak at 68 Hz will not exist.
Put a little polyester in the throat, and peaks will not be a problem.

OTOH, room effects are going to cause major problems