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CNC Speaker Design http://dcaudiodiy.com/phpBB3/viewtopic.php?f=4&t=942 |
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Author: | tomp [ September 2nd, 2018, 6:12 pm ] |
Post subject: | Re: CNC Speaker Design |
Cogito wrote: Quote: I have modeled several Tapped Horns, several Closed Back Horns, and several Transmission lines, but none of these designs have resulted in HORNRESP performance graphs that suggest they have any significant advantage over Infinite Baffle! If you are looking for better frequency response in horns, you will be disappointed. Typically horns are decade devices, even then too they start beaming on the higher end. In tapped horns, you will be lucky to get 2 octaves of usable bandwidth. The reason to get horns is their sonic qualities; detailed, extremely dynamic and uncompressed sound which no other type of audio device can replicate. Horns can be very dynamic, uncompressed, and with high efficiencies but there are other solutions that will give you the same or better results but with a much higher power requirement. The four 15" subs I have in sealed boxes are flat to 10 Hz with DSP EQ and have less than 4% distortion at 106 dB at an 11 ft listening postition at 10 Hz. Their sensitivity is 96dB. They have excellent transient response, low distortion and a low frequency response that cannot be matched with a horn having a mouth size anything less than a large house. However even at 96 dB, sensitivity is lower than a horn. At higher frequencies the horn can also control the radiation pattern lowering early reflections that can mess up coherence but at low bass frequencies the wavelengths are so long that they cannot exercise that control. However, that does not matter because most horn implementations cannot reach very low frequencies. Nothing against horns, but each solution has compromises and no one technology is supreme. |
Author: | Cogito [ September 2nd, 2018, 6:13 pm ] |
Post subject: | Re: CNC Speaker Design |
brombo wrote: You might consider an acoustic lens at the mouth of the horn to alleviate beaming. JBL used to do that. Those are cheap and sub-optimal tricks manufacturers resort to keep the costs low and sizes small. We DIYers do not have same limitations. |
Author: | Cogito [ September 2nd, 2018, 6:30 pm ] |
Post subject: | Re: CNC Speaker Design |
Quote: They have excellent transient response, low distortion and a low frequency response that cannot be matched with a horn having a mouth size anything less than a large house. Well, yes and no Tom. For the most sonically optical horn, you are right, mouth size is impractical for most of us. There are ways around it. Tom Danley applied for patent of Tapped Horn design. Mouth size is very small and lengths are quarter wavelength. By folding, size also becomes WAF compliant. See his white paper here: http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/01/The-Tapped-Horn.pdf Quote: Nothing against horns, but each solution has compromises and no one technology is supreme. Agreed. |
Author: | brombo [ September 2nd, 2018, 7:00 pm ] |
Post subject: | Re: CNC Speaker Design |
Also this - https://en.wikipedia.org/wiki/File:Elec ... n-1975.jpg http://www.xlrtechs.com/dbkeele.com/ |
Author: | chris1973 [ September 2nd, 2018, 8:34 pm ] |
Post subject: | Re: CNC Speaker Design |
brombo wrote: You might consider an acoustic lens at the mouth of the horn to alleviate beaming. JBL used to do that. Is that a tic tack toe kind of thing that splits the sound waves into several narrower paths? |
Author: | Cogito [ September 2nd, 2018, 9:42 pm ] |
Post subject: | Re: CNC Speaker Design |
brombo wrote: Also this - https://en.wikipedia.org/wiki/File:Elec ... n-1975.jpg http://www.xlrtechs.com/dbkeele.com/ Informative links, thanks. For home audio, the problem of both FR and beaming can be solved by using multiway horn system like Avant-garde Trio. |
Author: | brombo [ September 2nd, 2018, 11:02 pm ] | ||
Post subject: | Re: CNC Speaker Design | ||
Example of JBL horn with lens -
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Author: | Cogito [ September 3rd, 2018, 9:46 am ] |
Post subject: | Re: CNC Speaker Design |
Tom, Danley's products are geared towards pro-audio and HT markets. His primary design goals seem to be compact size for portability and very high spl around 45Hz for the thundering bass effects. He uses large high excursion and stiff woofers, IOW a typical HT sub driver. I am taking a different approach. Using two 8" high complaint and small excursion woofers (not subwoofers) in parallel push-pull configuration. My goal is to preserve the micro-dymanics in a low distortion and high efficient horn loaded sub. Hornresp modelling gives me flat 105dB from 35Hz to 100Hz. Attachment: FR curve is shown with high-pass and low-pass filters applied. Attachment: Attachment: If this is successful, I might build the 12" driver version which goes down to 25Hz flat. |
Author: | tomp [ September 3rd, 2018, 10:34 am ] |
Post subject: | Re: CNC Speaker Design |
Should be an interesting design for that frequency range. I'll be interested in hearing it. |
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