Need help with cone excursion!
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Hello all! Long time Toid follower and huge fan. Long story short, digging in to building my first set of speakers from scratch and am constantly running into an issue with all of my build where the cone excursion is way beyond x-max at rated RMS power in WinISD. Trying to avoid active DSP here. What are my options? Obviously the problem is resolved by adding a high pass filter cut off at whatever frequency is causing the most issues. Typically looking to cut off around 30-50hz to avoid issues on the smaller drivers. This particular build is using a single Dayton PS220-8 point source driver in an approx. 2.5ft3 box, tuned to 50hz. Curve looks great, but just can’t defeat that damned excursion! Still have more to learn, especially on crossovers, but am I correct that I can build a simple high-pass filter on the crossover to eliminate whatever freq’s needed? I like the idea of an in-line filter similar to what GR Research does buy I am just running a simple Chi-Fi tube amp that will not allow anything in-line prior to the unit (I think?). So my next option is to put some form of a high-pass filter on the crossover correct? Can someone help me understand if, and how tat looks like and what he positives/negatives are? 2 watts puts me over x-max running the driver full range, and I need to find a way to filter out those lowest frequencies. Any and all help is greatly appreciated!
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What are you using to model the speaker, WinISD? Can you post a screenshot of your results?
2.5 cuft seems just a tad big for that driver. Is that the default that the program gave you?
2 watts. Hmm. That seems a bit ridiculous to be reaching the limit, but it is a very efficient speaker. And if you have overexcursion that low, I’d have to look at the driver info to make sure it was input properly.
Really, the recommended level to use is about 80% of rated (rms). Taming of overexcursion tends to use a Linkwitz-Riley 4th order below port tuning gets it under control.
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Hey TVOR-Ceasar, thanks for the reply. Yep, I am using WinISD. I just re-entered all of the speaker data and restarted the build. Same result. 2 watts takes me over x-max. WinISD spit out a box volume of 2.426 tuned to 48hz. Parts Express website recommends 2.25ft3. This seems to be a re-occurring theme with the first handful of builds I have modeled in WinISD. Possibly something I am doing, but not sure what that is lol. Thanks for the input!
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That’s below the tuning frequency and happens naturally with ported designs. You’ll need to put a highpass filter on it – a Linkwitz-Riley, 4th order around 40Hz. That’ll tame it. Even at that, you can really only go about 25 watts and keep it in control. Granted, that puts you up at about 110 dB, which is very loud.
And yes, I ran the box by hand and came up with very similar size, so it’s what it needs.
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