Thanks, this helps in rationalising that adding sources doesn't necessarily result in a net excess.but below that it is very position dependent.
Does this make sense? If a speaker is designed to be put into a corner, it could be measured in that corner. A suitable measurement scheme would have to be developed to take in the space properly. Outside this space could be zeroed in the process of establishing DI.
It makes sense to me 🙂 The speaker in the corner has its DI changed from it not being in a corner, but this has to be specified in the calculations. In the modal region, of course, this is not true, but the equations don't work there anyways..
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DI is normally referenced to full space, isn't it? I think it should be in this case for a fair global comparison. Or were you talking about something else?The speaker in the corner has its DI changed from it not being in a corner,
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By switching phases you mean changing it from 0 to 180?It took me about 4 hours once I had the measurement system setup (that takes a lot of time.) I measure each sub and the mains and use EQ to smooth each independently. I was doing this in real time looking at the traces. Then I sum them up. I try flipping phases to get to the smoothest response without a lot of deep holes. Then I try to correct the sum with overall EQ (all sources.) If this doesn't get me where I want I might go back and tweak each individual sub.
Since I can't EQ all sources at once I'll have to set the same EQ settings at all subs and if that won't do I can tweak each sub individually.
Here is my ugly stereo response. A starting point. I'm not positive but you guys gave me some good guidance.
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By switching phases you mean changing it from 0 to 180?
Yes, I should have said "polarity": not "phase".
DI is normally referenced to full space, isn't it? I think it should be in this case for a fair global comparison. Or were you talking about something else?
Yes, it is reference to full space, but that doesn't require the source to actually be in full space. If it is in a corner then it has only 1/8 the space to radiate into so for an omnisource it has an 8 times larger DI (linearly not dB.) As the DI of the source goes up this multiplicative factor will go to zero.
True. 😉Yes, I should have said "polarity": not "phase".
What do you think of the response I shown? Solvable with three or more subs?
True. 😉
What do you think of the response I shown? Solvable with three or more subs?
Solvable by using more smoothing in your plot?
B.
Found this easy to understand:
Room acoustics - Wikipedia
Any experience with placing the subwoofer-woofer crossover frequency at exactly the Schroeder frequency?
Room acoustics - Wikipedia
The way that sound behaves in a room can be broken up into roughly four different frequency zones:
The first zone is below the frequency that has a wavelength of twice the longest length of the room. In this zone, sound behaves very much like changes in static air pressure.
Above that zone, until wavelengths are comparable to the dimensions of the room,[a] room resonances dominate. This transition frequency is popularly known as the Schroeder frequency, or the cross-over frequency and it differentiates the low frequencies which creates standing waves within small rooms from the mid and high frequencies.[2]
The third region which extends approximately 2 octaves is a transition to the fourth zone.
In the fourth zone, sounds behave like rays of light bouncing around the room.
Any experience with placing the subwoofer-woofer crossover frequency at exactly the Schroeder frequency?
Yes it is.Is that at listening position?
Not sure I understand. It's 1/48 smoothing which is basically no smoothing.Solvable by using more smoothing in your plot?
Ben, do you do childrens parties?
Beige, can it be done? It looks that way to me (no more than 3).
Beige, can it be done? It looks that way to me (no more than 3).
True. 😉
What do you think of the response I shown? Solvable with three or more subs?
It's typical.
"Solvable" - not sure what that means here. I can guarantee that with more subs - more degrees of freedom - the situation can be improved.
Any experience with placing the subwoofer-woofer crossover frequency at exactly the Schroeder frequency?
The Schroeder frequency Fs is defined as a single frequency, but the fact is that it is a broad range of transition approximated by the calculated Fs and it is impossible to actually define a single frequency. I don't use a subwoofer-woofer crossover, but the main transition is certainly within the Fs range in my room.
Well you use a assymetric subwoofer x-over it seems. I.e a LP on the subs but no HP on the mains. No?
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None of the filters in my system are symmetric.
I don't know how many times I need to say this, but a HP filter on mains is only required if the mains are power limited. I do not use one in my current system, but have in the past used a first order HP at a low frequency just to limit the cone excursion. The LP on the subs is at a different frequency and all three subs used a different frequency and sometimes slopes. The bottom line is whatever works. This idea of "coherency" of the LFs is nonsense. We hear the sum total of all LF sources at LFs - basically steady state - not individual separate arrivals.
I don't know how many times I need to say this, but a HP filter on mains is only required if the mains are power limited. I do not use one in my current system, but have in the past used a first order HP at a low frequency just to limit the cone excursion. The LP on the subs is at a different frequency and all three subs used a different frequency and sometimes slopes. The bottom line is whatever works. This idea of "coherency" of the LFs is nonsense. We hear the sum total of all LF sources at LFs - basically steady state - not individual separate arrivals.
In my system I use an active LR crossover (100Hz, 24db/oct.) with a single active (corner) sub and two small active main speakers. IME this sounds better than full-range main speakers and 'overlapping' subs. There's no distortion from pushing drivers outside their comfort zone and there are no audible phase problems.
My listening space is about 5m x 8m x 2.5m (16ft x 26ft x 8ft). LF room modes are not a problem. There's a variable amount of bass (and mids and highs) in different locations, like close to a wall versus the geometrical center of the room, but overall sound quality is good everywhere (even outside the room).
I think full-range main speakers (at least the ones I tried) interfere with a sub as a result of different phase behavior at low frequencies. Having this sorted is essential IMO and a proper crossover (analogue or digital) will do the job.
Also note that audible bass problems may be caused by distortion from jitter and/or bad power supplies and/or equipment grounding issues etc..
My listening space is about 5m x 8m x 2.5m (16ft x 26ft x 8ft). LF room modes are not a problem. There's a variable amount of bass (and mids and highs) in different locations, like close to a wall versus the geometrical center of the room, but overall sound quality is good everywhere (even outside the room).
I think full-range main speakers (at least the ones I tried) interfere with a sub as a result of different phase behavior at low frequencies. Having this sorted is essential IMO and a proper crossover (analogue or digital) will do the job.
Also note that audible bass problems may be caused by distortion from jitter and/or bad power supplies and/or equipment grounding issues etc..
Abtr
Sorry, but I will have to disagree. And I am not speaking for one, but hordes of people who have also tried this. I think that your position would be far into the minority.
Sorry, but I will have to disagree. And I am not speaking for one, but hordes of people who have also tried this. I think that your position would be far into the minority.
Since I don't use a crossover to the subs from the mains in much of the band I have five subs
This is what made med ask. Are you happy with the phrasing?
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Since I don't use a crossover to the subs from the mains, in much of the band I have five subs
Is that better?
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