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Low Earth Orbit
DIY Audio
60 Degree DIY Mid Hi - AKA PM60
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<blockquote data-quote="Peter Morris" data-source="post: 140624" data-attributes="member: 652"><p>Re: 60 Degree DIY Mid Hi</p><p></p><p></p><p></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">Looking really good .... +/- 2 dB 80Hz - 20KHz </span></span><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"> except for that bit around 500Hz that we will fix.<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" />~<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" />~:smile:</span></span></p><p></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">I suspect after a bit of tweaking you will get +/- 1.5 dB 100Hz to 20KHz, exactly as my original specification in my first post.</span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"></span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">I think the delay between the 12s and horn is not quite correct - you need to add some more delay to the HF and the same amount to the VHF. There should be no dip in the SPL or phase trace. </span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"></span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">There are two things that determine the delay you need -</span></span></p><p></p><p><span style="color: #3e3e3e"><span style="font-family: 'Symbol'">· </span></span><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">the different path lengths between the HF driver and the 12” horn</span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Symbol'">· </span></span><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">and the different phase response of the LF and HF horns </span></span></p><p></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">I have not done any IIR settings for the 60 degree horn, but I suspect it will have quite a different phase response to the 90 degree HF950. I'm painting my boxes at the moment and as soon as I have a chance I will do some IIR settings for the 60 degree version.</span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"></span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">One trick is to lower the crossover frequency to say 300Hz and look at the HF section only. If there are any peaks even below the normal crossover frequency (700Hz) you need to EQ them out. Then put the crossover back to 700Hz.</span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">You can also do the same with the 12 by increasing the crossover to around 2KHz and EQ the peaks out and go back to 700Hz.</span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"></span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">Then you just need to get the time alignment correct so the phase traces of the LF section and the HF section overlay each other. You should use the exact same mic position and time offset in Smaart.</span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"></span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">What you will find with this box because it behaves so well, any small changes will make avery noticeable difference. </span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"></span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">Also looking at the plot you may need a little more gain on the 12"drivers or boost in the low end ... 80Hz. It’s tricky to get the gain of the 12” and horn correct when you are measuring close to the box. I tend to look at what Smaart / Systune is telling me as well as having a good listen and adjust to taste.</span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'"></span></span></p><p><span style="color: #3e3e3e"><span style="font-family: 'Tahoma'">Yes the pattern of the 60 degree box is very tight. I think it will be excellent where you need a tight defined pattern or you want to use a pair of boxes each side for 100 to 120 degrees of coverage. In comparison the RCF HF950 has a very wide pattern.</span></span></p></blockquote><p></p>
[QUOTE="Peter Morris, post: 140624, member: 652"] Re: 60 Degree DIY Mid Hi [COLOR=#3e3e3e][FONT=Tahoma]Looking really good .... +/- 2 dB 80Hz - 20KHz [/FONT][/COLOR][COLOR=#3e3e3e][FONT=Tahoma] except for that bit around 500Hz that we will fix.:)~:-)~:smile:[/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Tahoma]I suspect after a bit of tweaking you will get +/- 1.5 dB 100Hz to 20KHz, exactly as my original specification in my first post. I think the delay between the 12s and horn is not quite correct - you need to add some more delay to the HF and the same amount to the VHF. There should be no dip in the SPL or phase trace. [/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Tahoma] There are two things that determine the delay you need -[/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Symbol]· [/FONT][/COLOR][COLOR=#3e3e3e][FONT=Tahoma]the different path lengths between the HF driver and the 12” horn[/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Symbol]· [/FONT][/COLOR][COLOR=#3e3e3e][FONT=Tahoma]and the different phase response of the LF and HF horns [/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Tahoma]I have not done any IIR settings for the 60 degree horn, but I suspect it will have quite a different phase response to the 90 degree HF950. I'm painting my boxes at the moment and as soon as I have a chance I will do some IIR settings for the 60 degree version. [/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Tahoma]One trick is to lower the crossover frequency to say 300Hz and look at the HF section only. If there are any peaks even below the normal crossover frequency (700Hz) you need to EQ them out. Then put the crossover back to 700Hz.[/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Tahoma]You can also do the same with the 12 by increasing the crossover to around 2KHz and EQ the peaks out and go back to 700Hz. [/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Tahoma]Then you just need to get the time alignment correct so the phase traces of the LF section and the HF section overlay each other. You should use the exact same mic position and time offset in Smaart.[/FONT][/COLOR] [COLOR=#3e3e3e][FONT=Tahoma] What you will find with this box because it behaves so well, any small changes will make avery noticeable difference. Also looking at the plot you may need a little more gain on the 12"drivers or boost in the low end ... 80Hz. It’s tricky to get the gain of the 12” and horn correct when you are measuring close to the box. I tend to look at what Smaart / Systune is telling me as well as having a good listen and adjust to taste. Yes the pattern of the 60 degree box is very tight. I think it will be excellent where you need a tight defined pattern or you want to use a pair of boxes each side for 100 to 120 degrees of coverage. In comparison the RCF HF950 has a very wide pattern.[/FONT][/COLOR] [/QUOTE]
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60 Degree DIY Mid Hi - AKA PM60
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