I currently have a pair of rs100-4 full range drivers that I'm building into a FAST system with a pair of 12 inch infinity subs. I'm planning on having the crossover somewhere between 120-200 hz which I haven't determined where I'm going to set the crossover frequency yet until I build it, but most likely around 150hz 12db/octave.
My question is I had originally thought you don't want subs crossed above around 60-80 hz where your ears can start picking up positioning but my question is if I put the subs in a separate cabinet right behind the speakers along the wall crossed at 150hz would I run into any problems? There may be some obstacles in the direct path from where the subs are to the listening position which is why I wasn't sure if this would have any effect up to 150hz.
Also if it doesn't really make sense what I mean I can upload pictures as well
My question is I had originally thought you don't want subs crossed above around 60-80 hz where your ears can start picking up positioning but my question is if I put the subs in a separate cabinet right behind the speakers along the wall crossed at 150hz would I run into any problems? There may be some obstacles in the direct path from where the subs are to the listening position which is why I wasn't sure if this would have any effect up to 150hz.
Also if it doesn't really make sense what I mean I can upload pictures as well
You probably know these few things. Keep the sub as close to the upper range as possible. Place the subs and the upper range where they perform best in their range in the room. Crossover lower means higher flexibility in placement. Juggle it around for the least in compromises. A steeper crossover will probably help.
Going with the 1/4 wavelength rule if you cross at 200Hz the sub should be no more than 42cm (1.37ft) from the wide-range driver (c-t-c) and at 120Hz no more than 70cm (2.3ft).
You should verify if your subs can sustain a 200 Hz crossover with acceptable distortion, as many are designed to operate under 100 Hz only (you are looking at a woofer and not at a sub truly).
Ralf
Ralf
4" drivers usually have terrible distortion below 3-400Hz. Try to get xo around 2-300Hz, that should be easy even with built-in amps. It is more difficult to control xo slopes to get good phase match. Subwoofer's distortion at 200Hz will not be a problem. A dsp control will help, minidsp 2x4 or similar makes life easier. if you can route the main speakers through it too.
I do have a minidsp and so I was going to play around with crossover points, just my estimate was that I would land somewhere around 120-200hz cause when I've run the full range drivers at 150hz I could get up to 40 watts or so before hitting xmax and that's way louder than I would listen and I thought having high excursion is the main source of added distortion, but are smaller drivers just worse at lower frequencies?
Zaph tested the Dayton driver: Zaph|Audio
You can have a look at the graphs and draw your own conclusion, but I wouldn't cross it below 150-200 Hz.
Ralf
You can have a look at the graphs and draw your own conclusion, but I wouldn't cross it below 150-200 Hz.
Ralf
I prefer dual crossover points, meaning that you have a high-pass filter on the speakers set to something like 80 Hz, and then set the subwoofer's low-pass filter to 100 Hz. This overlap does create a "hump" in frequency response, but bearing in mind that human ears do not have perfectly linear frequency sensitivity there is nothing wrong with this. The blending of low frequencies between the speakers and sub also makes it very difficult to pinpoint the location of the subwoofer. I find that this configuration really gives music like rock a type of punch that you usually only experience at a live performance.
Funny, I try and avoid overlap as much as possible and almost wander into 'gap' territory if I am using passive XO's. The reason for this is that no two drivers attempting to reproduce the same frequency, sound the same, and that difference, I find clouds the whole presentation.
Maybe why I like active XO's with steep slopes. 🙂
Maybe why I like active XO's with steep slopes. 🙂
Cal, the gap or spread in the crossover often gives flattest response. It can also help the crossover phase, which helps response.
C-to-c spacing between drivers: One rule of thumb (ie not gospel) is the crossover frequency WL/4 rule (eg 1/4 * Speed of Sound/crossover frequency). Think you have greater flexibility the further afield your seating position is from the speakers (ie drivers need to sum properly).
Stereo subs/flanking woofers vs mono subs: Flanking subs (I believe a term coined by Wayne Parham) can be run higher than mono subs (generally upto 200Hz) if kept close to mains. However, your application sounds more like a two-way though where you're using the sub just to provide the midbass/bass. If it was me, I'd follow Juhazi's suggestion and try to run the subs a little higher for starters. I'm running some TBW3 3" fullrangers with 8" woofers OB nearfield (different but similar application) and prefer to have the woofers handling the lower mids (eg approx 600Hz acoustic crossover).
Acoustic crossover: Aiming for -6dB acoustic crossover point to get a flat response currently works for me. Maybe give that a go too. If using MiniDSP's advanced 2 way stereo plug-in, you can see the expected acoustic crossover when you position the cursor over the intersecting slopes on the crossover graph.
Hope this helps.
Stereo subs/flanking woofers vs mono subs: Flanking subs (I believe a term coined by Wayne Parham) can be run higher than mono subs (generally upto 200Hz) if kept close to mains. However, your application sounds more like a two-way though where you're using the sub just to provide the midbass/bass. If it was me, I'd follow Juhazi's suggestion and try to run the subs a little higher for starters. I'm running some TBW3 3" fullrangers with 8" woofers OB nearfield (different but similar application) and prefer to have the woofers handling the lower mids (eg approx 600Hz acoustic crossover).
Acoustic crossover: Aiming for -6dB acoustic crossover point to get a flat response currently works for me. Maybe give that a go too. If using MiniDSP's advanced 2 way stereo plug-in, you can see the expected acoustic crossover when you position the cursor over the intersecting slopes on the crossover graph.
Hope this helps.
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