Hornresp question
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Category: General
Forum Name: Advanced Discussion
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=6158
Printed Date: 27 March 2026 at 2:16am
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Topic: Hornresp question
Posted By: julienb34
Subject: Hornresp question
Date Posted: 22 August 2006 at 9:30am
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Why Hornresp seems to cut the highs in the SPL response? The same design in AJhorn demo (exponential) doesn't cut the high as Hornresp. Is there something to do in hornresp? Thank. |
Replies:
Posted By: Mircea Bartic
Date Posted: 22 August 2006 at 9:57am
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I believe that hornresp does not take into acount tha response of the driver in direct radiator mode. The plot represents the bandpass response (theoretical) Hornresp was initially designed for basshorns ------------- general manager & head designer at nexus-acoustics research http://www.facebook.com/nexus.acoustics.research" rel="nofollow - http://www.facebook.com/nexus.acoustics.research Ex Nexus_3 |
Posted By: tb_mike
Date Posted: 23 August 2006 at 7:47pm
| I Guess you could sum the driver frequency response as measured in 2pi from the manufacturer. Note that strong drivers with low Qes have a nice rising response for a higher frequency F3 |
Posted By: ceharden
Date Posted: 24 August 2006 at 4:23am
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Might this also be to do with Hornresp plotting the power response ie
averaged across all radiation angles. Try looking at the on-axis
response? (Tools -> Directivity -> 0deg) I might be completely wrong.... |
Posted By: Centauri
Date Posted: 29 August 2006 at 11:38am
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I believe Hornresp's maths includes the mass-rolloff equations, which some now doubt as being correct. The directivity tool seems to exaggerate the top end, most likely because it models round horns with curved sides, which will have poor dispersion characteristics. If you are building square straight-sided horns, then build-and-measure is the order of the day. Cheers Graeme |
Posted By: james folkes
Date Posted: 30 August 2006 at 3:42am
ok, tried that... right, now this confused me significantly. what i really wasn't expecting was the 12dB incease over the previous plots, 12 frickin' dB man! i'm fiddling up some 12", 8" + 1" top boxes to accompany the project firewood bass bins and to try two ideas that might be relevant to the mid top project, what's good is that brought the output level of the 8" back in line with the 12" at full power (much higher actually), which is what i was expecting, other than that i'm just confused. question for both you and greame, fast initial expansion to assist in top end response of horn... i've seen the phrase written down a few times, but i'm having difficulty equating it to my hornresp furtlings. could you please talk about this slightly more? james. ------------- mardy hippy. |
ceharden wrote:Posted By: tb_mike
Date Posted: 30 August 2006 at 11:29pm
| James - You can use the autocalc thingie,and hornresp calculates the cutoff for each segment. Have you got MSN? |
Posted By: james folkes
Date Posted: 31 August 2006 at 4:44am
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i thought that was the lower cut-off...
anyway, jamesatinddotst "at" hotmail.com is my msn thingumy, looking forward to having a natter! james. ------------- mardy hippy. |
Posted By: Centauri
Date Posted: 02 September 2006 at 8:51am
This is a trick Bill Fitzmaurice uses to get a wider bandwidth from his horns. If you have an exponential horn with a lower cutoff of say 200Hz, you will get a lot of gain at the lower frequencies but not much at the top end. If you break the horn into 2 sections with the first exponential section with a cutoff of around 500Hz or more, then follow it with the second exponential section at 200Hz, you can get a bit more out of the top end. The trick is juggling the frequencies and lengths of the two sections to get a reasonably smooth response. Due to Hornresp's top end innacuracies, and the fact it does not take into account the measured response of the driver used, a lot of experimenting can be expected to get good results. When looking at the directivity results from Hornresp, the high gains will only appear on axis, and the top end will fall off rapidly at off-axis angles. If you are using a straight-sided horn for controlled directivity, these results will not mean anything. Cheers Graeme |
Posted By: tb_mike
Date Posted: 14 September 2006 at 3:54am
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