I am using stereo subwoofers with full range active 3-ways for the first time. The system is for music only, no movie effects. The subwoofer low pass is 70 Hz and is carefully phase aligned with the 3-ways woofer at this frequency. Should I install a woofer high pass at 70 Hz also? I realise this will save the woofer from exertion at low frequencies so it can possibly play cleaner in its pass band, but is there any downside? Is it preferable to avoid additional phase shifts caused by the extra crossover?
If this were not a subwoofer cross then I would expect you to follow with the needed phase and that means if the mains roll off already, it represents their already being crossed. In a sense you are limited there.
However as a sub cross, phase may be taken differently with the room getting involved. Consider the benefit of multiple sub placements being helped by the mains lower frequency response. Otherwise you're just making these subs part of the mains and you'll want other subs as well.
However as a sub cross, phase may be taken differently with the room getting involved. Consider the benefit of multiple sub placements being helped by the mains lower frequency response. Otherwise you're just making these subs part of the mains and you'll want other subs as well.
The mains are well out into the room for best imaging (1.8 m or 6 ft from the nearest boundary). The stereo subwoofers are behind the speakers close to the front wall. At the subwoofer 70 Hz crossover the mains are starting to drop, since there is little boundary reinforcement with their positioning, so I suppose the mains response is well down in the sub range anyway. There seems to be be a consensus that carefully positioned multiple subs can produce a mode even bass in the room, which is why I am enquiring about leaving the mains not high pass filtered to contribute to the sub-bass, albeit at a reduced level.
Hi,
It makes plenty of sense to use subs. If you're rolling off at 70hz to the subs, this implies your mains are far from full range. Maybe it's just terminology, but I expect a full range speaker to play to 30hz in a room, and not just as its F6. F3 could be acceptable, but I would want F3 under 30hz to call it a full range. If that were the case, you'd probably not be considering subwoofers?
Your best friend in this is a calibrated microphone and REW so you can look at the response in room and carefully tweak the subs time and phase as needed so its a seamless integration. Integration is the hardest most delicate part of the subs with your stereo system.
Yes you'd want highpass & lowpass on the sub if you play content back that actually will reach down to the teens and potentially ask your driver to do something it cannot. I wouldn't stress it on your mains though, if they're full range. Their roll off will be steep, so you wouldn't notice. And distortion due to xmax exceeding in bass frequencies is not going to be noticeable by ear usually.
Very best,
It makes plenty of sense to use subs. If you're rolling off at 70hz to the subs, this implies your mains are far from full range. Maybe it's just terminology, but I expect a full range speaker to play to 30hz in a room, and not just as its F6. F3 could be acceptable, but I would want F3 under 30hz to call it a full range. If that were the case, you'd probably not be considering subwoofers?
Your best friend in this is a calibrated microphone and REW so you can look at the response in room and carefully tweak the subs time and phase as needed so its a seamless integration. Integration is the hardest most delicate part of the subs with your stereo system.
Yes you'd want highpass & lowpass on the sub if you play content back that actually will reach down to the teens and potentially ask your driver to do something it cannot. I wouldn't stress it on your mains though, if they're full range. Their roll off will be steep, so you wouldn't notice. And distortion due to xmax exceeding in bass frequencies is not going to be noticeable by ear usually.
Very best,
For music.
Crossing over at 70 Hz means the main speakers are playing all the music and the sub are just low bass effects. At 70, the main speakers are being asked to play lots of stuff at 35 Hz (quite low organ notes) although the subs at 140 Hz, don't interact with the stereo image on music when using sharp slopes and clean speakers.
The cone motions at low freq are quite large and really wise to not send low notes to the mains if you value clean sound. Maybe 90 or 100 Hz better.
B.
Crossing over at 70 Hz means the main speakers are playing all the music and the sub are just low bass effects. At 70, the main speakers are being asked to play lots of stuff at 35 Hz (quite low organ notes) although the subs at 140 Hz, don't interact with the stereo image on music when using sharp slopes and clean speakers.
The cone motions at low freq are quite large and really wise to not send low notes to the mains if you value clean sound. Maybe 90 or 100 Hz better.
B.
Yes, 70 Hz roll-off to the subs is not really full-range. The mains woofers are over a pass band 70-150 Hz. The mids are wide band.
I am confident the subs can reach to the teens. I have tested 17 Hz at high levels though I don't have much music with such low frequency content. I have a sub high pass at 15 Hz for safety.
The 70 Hz low pass for the subs is because many claim the ear can positionally locate frequencies above about 80 Hz.
100-200 Hz for subs would seem to fly in the face of this claim. Is it a myth? I don't know either way from first hand.
This is the aim, hoping for a more coherent image.
The sub low pass at 70 Hz is LR 48 dB/octave.
Again, would not 90-100 Hz identify the sub location?
I am able to closely time alignment the sub and woofer at the 70 Hz crossover and I am assuming the woofer drops off sufficiently quickly below 70 Hz (without a high pass crossover) to avoid destructive interference. I have attached 2 RTA two channel pink noise plots at the listening position without sub and with sub added. With no sub the main speaker has a slight bass hump in the 63-126 Hz region. Just adding the sub with no woofer high pass produces a more even response down to 20 Hz. I have an impression that on some music, without the sub sounds punchier, but with the the sub, music such as string bass sounds more lifelike. I need to try the woofer high pass to see if anything changes.
This is my first experience of integrating a sub into a music system. I have used full range loudspeakers (2x10" woofers) for the past 20 years and just want to find out if I can get equal or superior results from a more compact 3-way plus stereo subs.
Attachments
Sub newbie here, I've always been a fan of big speakers but lately been enjoying cheap 3" full range that go as high as my ears and as low as about 150Hz. Such imaging! But obviously a couple of octaves missing.
So it looks feasible to use these with a sub up to 150 or 200?
Apologies if this isn't the right thread.
So it looks feasible to use these with a sub up to 150 or 200?
Apologies if this isn't the right thread.
That's something I'd considered, putting subs into the same box. So it'd be like a "traditional" 2 way but with the crossover out of the way, like 200Hz instead of 2k. I think the absence of a crossover in the middle of the ear's most sensitive area is why the FRs sound so good. A pair of B139s would be nice if they weren't unobtanium/$$$.
I actually lusted after a set of B-139s and finally found an affordable pair and bought them
After using them for a while I resold them; they are nothing special when compared to modern drivers
After using them for a while I resold them; they are nothing special when compared to modern drivers
That sounds about right, I think nostalgia is a thing in my case...a friend had an enormous pair of transmission line speakers with B139, B110 and T27 and he used them to introduce me to the Agrovators
To me that proves that you are experiencing destructive interference with the sub added, if everything was in phase and summing contructively that midbass hump would get higher not lower.
Well spotted. I was scratching my head until I remembered my sub amps are based on ICE modules which have reversed phase outputs. I swapped the sub phase, eliminated the bass peak and now the sub adds without changing bass levels above the x-over at 70 Hz. I also learned the futility of phase matching with single tones at bass frequencies. The room acoustics messes with the phase to make comparisons unreliable. Better to use a wide-band signal (pink noise or pseudo-random noise).