Hi,
my 2 way faital 15pr400 and hf108 measure nearly perfect after dsp equalization (camilla dsp).
Pic shows mesaured them individually and both the same time.
The response is worse, when measured both the same time (blue line). Does it make sense to equalize it to flaten the response?
What`s the reason for the blue response? The mic was placed in the middle when measured (runtime difference was zero from left vs. right).
my 2 way faital 15pr400 and hf108 measure nearly perfect after dsp equalization (camilla dsp).
Pic shows mesaured them individually and both the same time.
The response is worse, when measured both the same time (blue line). Does it make sense to equalize it to flaten the response?
What`s the reason for the blue response? The mic was placed in the middle when measured (runtime difference was zero from left vs. right).
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To get the red and green responses you appear to have already EQed at the listening position. This is not necessarily ideal, but to go any further you'd have to discover what else is happening behind it.
Not shure, if I understand what you mean.
All three measurements had been done at the listening position. All with the DSP engaged. If both speakers are measured the same time, I get the blue graph. If measured separate, I get red and green lines.
Some regions cancel each other in the blue line.
Could this be reflections from the room, that lead to phase cancelations between left and right?
All three measurements had been done at the listening position. All with the DSP engaged. If both speakers are measured the same time, I get the blue graph. If measured separate, I get red and green lines.
Some regions cancel each other in the blue line.
Could this be reflections from the room, that lead to phase cancelations between left and right?
EQing at the listening position gets you the wanted response without consideration of anything off-axis. It might seem like a place to start but as you are seeing, it's more of a side step.
With the right speakers which don't conflict with the room, you can naturally get a good response at the listening position. However, when this doesn't happen you sometimes need to break away from the flat response at the listening position to compensate for room power issues. It won't be perfect, nothing will in that case, but it will be optimum.
With the right speakers which don't conflict with the room, you can naturally get a good response at the listening position. However, when this doesn't happen you sometimes need to break away from the flat response at the listening position to compensate for room power issues. It won't be perfect, nothing will in that case, but it will be optimum.
These are the norm when measuring left and right speakers at once if the test signals are correlated. The speakers and microphone would have to be perfectly positioned for this not to happen. Your biggest deviations are in the higher frequencies where wavelengths are small enough that it's almost impossible to position things well enough to avoid issues.
In the days of pink noise/RTA testing there were uncorrelated versions for just this reason.
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Thanks for sharing…….this is precisely why beating a response into submission with EQ (phase shifting) is a bad idea. One only needs to examine the vast variety of microphones available for recording where a seasoned engineer will choose the right mic and location to eliminate the need to EQ the signal as its destructive.
Indeed and to make things more interesting our pair of ears and a brain don't hear what a microphone measures when the wavelength of the sound is short enough for the signal to be significantly different at each ear.
It looks like floor and ceiling reflection are also EQ'd away, which likely makes power response bit silly, as AllenB tipped out.
I speculate that if you move mic say 1m closer to speakers the first reflections shift in time and have bit different spectra and the response gets worse than without EQ.
Be really cautious correcting room effects to one spot, as it gets worse everywhere else, including the other rooms the sound gets to. This is why speakers are usually tuned by anechoic response, and then touched a bit in the room, mainly balancing the spectum in broad strokes, and perhaps knock down some modal peaks, relatively minor stuff, leaving the response at listening spot bit wonky looking but likely sounding quite fine throughout the house.
I speculate that if you move mic say 1m closer to speakers the first reflections shift in time and have bit different spectra and the response gets worse than without EQ.
Be really cautious correcting room effects to one spot, as it gets worse everywhere else, including the other rooms the sound gets to. This is why speakers are usually tuned by anechoic response, and then touched a bit in the room, mainly balancing the spectum in broad strokes, and perhaps knock down some modal peaks, relatively minor stuff, leaving the response at listening spot bit wonky looking but likely sounding quite fine throughout the house.
Thanks guys, understood...
I'll try a moving mic measurement next time.
All in all the speakers sound not bad. But the region arround 1k Hz is too loud; some (female) voices tend to pierce your ears...
Btw. the horns (McGee hl-1018) are very cheap and not bad, if you modify them a bit:
A layer of bitumen arround them and some putty inside of the horn throat takes care of that.
BR
Olaf
I'll try a moving mic measurement next time.
All in all the speakers sound not bad. But the region arround 1k Hz is too loud; some (female) voices tend to pierce your ears...
Btw. the horns (McGee hl-1018) are very cheap and not bad, if you modify them a bit:
A layer of bitumen arround them and some putty inside of the horn throat takes care of that.
BR
Olaf
If you draw a straight line between your 200 Hz and ~15 kHz points, then equalize to that, it might help. Your current response seems a couple dB hot through most of the midrange given the rest of the curve. In the end, your ears tell you what's right and not. A flat in-room response may not be to your liking, and that's OK.
You could have issues in the horns also. Sometimes they have narrow bands that need suppression to sound more natural. Those aren't always apparent on a single measurement. Comparing your speaker to a known good reference speaker (or headphones) while listening to pink noise can sometimes make problem areas more apparent.
That is something that I hear a lot – together with a lot of arguments that dismiss in-room XO tuning – but can’t get to agree (or maybe fully understand).
Here come a lot of "ifs": If the speakers are in a dedicated listening room, if they will be in the room virtually forever, if I am the only person to listen to it, if I have a single armchair that is "perfectly" positioned in the room and if I don't have to worry about the sound in the rest of the house, then WHY would I have to go with quasi-anechoic measurements to tune my active XO? It will be tuned to an environment that is completelly different than the one the speakers will be. Wouldn't it make way more sense to tune everything taking into account room interaction? Wouldn't be better if I tune the speakers so that they sound perfectly whem I am seated in my armchair - even if it sounds worse on the rest of the room/house?
Yes, I suppose equalizing between 200- 15k might help.I will give it a try.
And about the horn; it's shurely not optimized concerning the sound path.
I did have good results (Sound wise) with the moving mic method. That's also one thing I'm going to try.
I'm also in the "measuring at listening position" camp. I once tried nearfield with short windows and a second measurement at the listening position. So I endet up with 2 correction curves per speaker. The result soundwise was not better than a single measurement at LP.
And about the horn; it's shurely not optimized concerning the sound path.
I did have good results (Sound wise) with the moving mic method. That's also one thing I'm going to try.
I'm also in the "measuring at listening position" camp. I once tried nearfield with short windows and a second measurement at the listening position. So I endet up with 2 correction curves per speaker. The result soundwise was not better than a single measurement at LP.
In case it wasn't clear, the black bar here is the kind of target I meant in my 200 Hz to 15 kHz comment. Many listeners prefer a gradually downward sloping in-room response, and this tuning would more closely resemble that. How much tilt you like is personal preference, and a hotter presentation has become more accepted recently. If you don't like that, you just don't though. A more forward presentation can give new speakers wow factor because they sound highly detailed and dynamic, but it can also be fatiguing over time to some (or instantly on the wrong song).
Yes Mattstat, was clear to me.
I also like the downward slope. A straight line is way too bright for me.
With my Acoustats the slope is even stronger, up to 8 dB at 20 kHz.
I also like the downward slope. A straight line is way too bright for me.
With my Acoustats the slope is even stronger, up to 8 dB at 20 kHz.
I like speaker response flat 54-14000 hz. Above that I can't hear. My room with carpet, acoustic ceiling tile, urethane stuffed couches, bookshelves & record shelves 6' tall, organ speakers, 3 organs, 2 pianos, 3 tables, takes care of damping the highs. Also breaks up the standing waves 100-500 hz. With 6 db down dispersion of 90 degrees, sound is the same over 14' x 27' area.
So the point is you try to equalise to what sounds natural. If you can't seem to do it, start blaming the acoustic conditions.
Hi,
there is likely million reasons why, I bet Toole book has some of it, many threads in the forum as well. But we could just try and reason as it's fun activity 🙂
I'll make an example from practical point of view so I don't actually have to explain anything as I don't know too deep into details of differences between mic making a graph and how hearing system works. Assuming frequency response was all that matters for perception and that positioning matters:
when I acquire speakers and a room I would not know what's ideal or "perfect" positioning in a room is. To find it, I would have to always redo all measurements and tune the EQ if anything changed in the room, which are as I'm trying to find optimal positioning. It would be very tedious task and If you imagine the process you'd hear sound changing all the time, literally, as you move around moving things and measuring and adjusting EQ, would you notice the second somewhere in between when the sound was good? The frequency response is almost always flat because you always flatten it, so why not just pick the first practical position and call that "perfect"? I bet one would just leave the system on the first guessed position, but is it the best one?
So, it is very practical to tune a speaker without influence of a room, to some baseline performance, go find the perfect position, and you'd just tune it afterwards in the room if you wish. At this point, if you found the perfect spot, you could EQ to hearts content because you have a baseline to compare against. Just be careful with what you compensate with the EQ, because you can change the result by varying windowing or smoothing on your measurement, or if anything moves in the room, and the result is not flat anymore.