Tapped horn for PD 186 ?

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   I am busy reworking the 30Hz design at the moment. But 150W does seem very low.
Got to remember that x-max figure accounts for no compression effects and so probably would be at least double that in reality - Might be a bit too much for the PD186 
When I designed the TH18 I was gunning for a 1KW Cab - With some of the more capable modern 18" drivers some users are putting over 2KW into the TH18 tapped horn design.
Tony Wilkes reworked the TH18 as the TH18 EX and made it bigger - Again this resulted in lower SPL.
I estimated about 350- 700W in the Jbell Box - So maybe a smaller sized cab would be in order if you want to try a tapped horn design.

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Xoc1 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 397	Post Options Post Reply Quote Xoc1 Report Post Thanks(0) Quote Reply Posted: 23 April 2015 at 10:36pm
	I am busy reworking the 30Hz design at the moment. But 150W does seem very low. Got to remember that x-max figure accounts for no compression effects and so probably would be at least double that in reality - Might be a bit too much for the PD186 When I designed the TH18 I was gunning for a 1KW Cab - With some of the more capable modern 18" drivers some users are putting over 2KW into the TH18 tapped horn design. Tony Wilkes reworked the TH18 as the TH18 EX and made it bigger - Again this resulted in lower SPL. I estimated about 350- 700W in the Jbell Box - So maybe a smaller sized cab would be in order if you want to try a tapped horn design.

Xoc1 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 397	Post Options Post Reply Quote Xoc1 Report Post Thanks(0) Quote Reply Posted: 24 April 2015 at 11:14pm
	OK I had some time to run some sims. Half a G sub is about 167 litres and tuned to about 39hz from quick calculation on the dimensions. The PD 186 runs out to x-max at about 63.5V - 500w @ 8 ohms Peak SPL is 124.6db at about 57hz All good stuff. 4th order filter needed was 31hz Then I run a sim for the Xoc1 TH18 Response is not very smooth - this cabinet likes drivers with a bit higher BL Running to x-max takes slightly less 60V - 450w @ 8 ohms Peak SPL is 129db at 51Hz but here is a dip in the passband to 125.3 @ 72hz 4th order filter needed was 27hz First Pic is TH18 with PD186 at xmax & hi pass 2nd pic is 1/2 g sub with PD186 at xmax & hi pass 3rd pic is unfiltered comparison at x-max. Hope this helps.

Xoc1 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 397	Post Options Post Reply Quote Xoc1 Report Post Thanks(0) Quote Reply Posted: 24 April 2015 at 11:43pm
	Just for reference here is the PD1852 in the Xoc1TH18 driven to x-max 87.2V 950W@8 ohms - Far smoother!

_djk_ Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 23 November 2004 Location: United States Status: Offline Points: 6002	Post Options Post Reply Quote _djk_ Report Post Thanks(0) Quote Reply Posted: 25 April 2015 at 7:27am
	http://i56.photobucket.com/albums/g196/dkleitsch/PatsPA_zps297453f4.jpg Smaller (24" x 24" x 32"), lower (-3dB at 35hz), and louder (over 130dB with 1KW input). In the USA these woofers are less than $100 each. PPSL is much simpler to build, no angles! Hits x-max with 1200W/4Ω input, flat to 35hz.
	djk