I have spent a great deal of time learning about competent speaker design, and the biggest influences of preference, in coordination with room acoustics.
My project has settled on the following requirements: 95db SPL max at 4-5m, low distortion. as close to full range as possible (-3db ant 20hz) and dimensions up to 14x17x52 (WxDxH) inches. Based on Dr. Toole's research of bass producing so much tonality preference (and indeed my own testing), I am prioritizing a strong low-end to guide mid range and high range driver selection.
I am passing back and forth on whether to include subwoofer boxes inside my custom towers (I am still leaning on doing it). But only if I can get relatively full range, with a high enough sensitivity - at least 88db at 1m, with a single 10 or 12in woofer/subwoofer, so I can include a subwoofer section beneath it, independently controlled (all passive), DSP at A/V processor. If I can't, I'll have to leave the sub as separate.
I have been simulating designs and boxes with WinISD, and the crossovers and performance in VituixCAD, and achieved some excellent results on paper. But now the real world...
Onto the topic: to help achieve stated goals, I have moved away from large sealed boxes to still large, but smaller boxes, playing with passive radiator options.
However, there is no free lunch. The only parameter I cannot meet is the group delay is through the roof in WinISD. Like off the charts to get 20hz extension -3db.
I have searched several forums including DIYAudio, and AVS Forums, and cannot find enough objective data on how much passive radiators influence group delay and perceived bass quality in certain frequency ranges. Since they have become so popular in recent designs that measure well, I'd really like to understand why group delay is not impacting those designs, and real world listening results, and/or what they did to overcome the limitations.
Does anyone have handy calculations, or information specific to group delay increases relative to size of passive radiator, or the T/S parameters of the radiator?
What information do we have on room acoustics of rear-facing passive radiators? Does a speaker need more distance from the back wall?
Thank you in advance!
My project has settled on the following requirements: 95db SPL max at 4-5m, low distortion. as close to full range as possible (-3db ant 20hz) and dimensions up to 14x17x52 (WxDxH) inches. Based on Dr. Toole's research of bass producing so much tonality preference (and indeed my own testing), I am prioritizing a strong low-end to guide mid range and high range driver selection.
I am passing back and forth on whether to include subwoofer boxes inside my custom towers (I am still leaning on doing it). But only if I can get relatively full range, with a high enough sensitivity - at least 88db at 1m, with a single 10 or 12in woofer/subwoofer, so I can include a subwoofer section beneath it, independently controlled (all passive), DSP at A/V processor. If I can't, I'll have to leave the sub as separate.
I have been simulating designs and boxes with WinISD, and the crossovers and performance in VituixCAD, and achieved some excellent results on paper. But now the real world...
Onto the topic: to help achieve stated goals, I have moved away from large sealed boxes to still large, but smaller boxes, playing with passive radiator options.
However, there is no free lunch. The only parameter I cannot meet is the group delay is through the roof in WinISD. Like off the charts to get 20hz extension -3db.
I have searched several forums including DIYAudio, and AVS Forums, and cannot find enough objective data on how much passive radiators influence group delay and perceived bass quality in certain frequency ranges. Since they have become so popular in recent designs that measure well, I'd really like to understand why group delay is not impacting those designs, and real world listening results, and/or what they did to overcome the limitations.
Does anyone have handy calculations, or information specific to group delay increases relative to size of passive radiator, or the T/S parameters of the radiator?
What information do we have on room acoustics of rear-facing passive radiators? Does a speaker need more distance from the back wall?
Thank you in advance!
