Don't you find raw measurements (with significant window length) difficult to work with when it comes to EQ without using either spacial (multiple measurement locations), temporal (gating) or frequencial (1/n octave smoothing) averaging?...
Another example from our living room in primary listening setup (right ch). Red=super-cardioid (KS-1804), yellow=dipole (MG-3.5/R), green=monopole on stand (8260A).
An externally hosted image should be here but it was not working when we last tested it.
Huge mid-bass dip with monopole and mid-bass hump + upper bass loss (fat, slow & unintegrated 😉) with dipole are typical in setups & rooms with same kind of geometry.
Unfortunately that dipole implementation is diversely weak, and for example Gradient Revolution or any decent diy dipole with cone drivers would give substantially better result.
There is 1/24 octs smoothing but I think my message is clear; I don't have competitive choice for super- or hyper-cardioid as pure stereo in that room & position. Turning of listening direction 90 degrees would decrease performance differences quite much, which makes possible to get satisfactory result also with very carefully located monopoles. No better than super-cardioid, but good enough to listen music if other qualities of speaker are ok.
Sorry about repeated OT and not always polite responses to unfounded dismissive sarcasm. Case closed.
I know the feeling - that green dip at 60hz and hump at 30hz mirrors my room exactly. I don't have the space to do anything about it though 🙁
I don't use gating at LFs because I want to EQ the steady state response. I usually do some spatial averaging but at frequencies < 100 Hz. there is not much spatial variation. All of my (custom) software has some averaging capability, but in a well damped room the response usually does not need much averaging. Remember we are talking only about modal frequencies here. At least that is what the OT discussion was about. Above the modal region is an entirely different problem. I would never use EQ above the modal domain.
@Kimmosto:
Of course i realise that inroom response depends very much on placement. I saw once inroom response like that red one with monopole - but i think that the guy was very lucky.
I don't know if that is luck with positioning of KS-1804 but it sure looks fine. In my room i don't have as much problems but there is dip of 8dB at 220-250Hz that i just can't get rid of.
cheers
Of course i realise that inroom response depends very much on placement. I saw once inroom response like that red one with monopole - but i think that the guy was very lucky.
I don't know if that is luck with positioning of KS-1804 but it sure looks fine. In my room i don't have as much problems but there is dip of 8dB at 220-250Hz that i just can't get rid of.
cheers
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Hi Zvu
Sounds familiar. I think the notch is caused by floor bounce.
Here's my 2-way with a ZA14+XT25 1 meter above the floor. Nice deep notch at about 150Hz. I don't get the hump lower down because my room is not entirely closed. At the other end of the room, there's an open staircase that leads to the floor below. It acts like one huge bass trap.
Regards
Mike
Case was closed but to avoid open questions... 🙂
There is also luck due to room length and rear wall acoustic properties, but the result would be quite equal within couple m2 area in that channel. Maybe you have seen this animated gif in KS-585 doc.
Speaker to front wall distance varies from 80cm to 180cm with 20cm steps, totally 6 meas. From speaker to mic is constant 260cm (smoothing is about 1/4 octs @ 20 Hz due to short time window of justMLS, 1/6 octs at midrange and above).
Some interfering reflections from side and rear walls are visible, but generally speaker works here like a train toilet due to absence of first order front wall and front corner reflections. More massive rear wall (=behind listener) causes more trouble if pattern is true cardioid (still less than with monopole). Inverted back wave of hyper-cardioid increases possibilities to partially neutralize effects of rear wall (just like with true dipole) along with higher DI.
Despite of some advantages I don't have a plan to make new speakers with cardioid bass within few years. Waiting for inspiration with 2.5-way decor speakers...
I believe in the 40's and 50's 500 was the preferred crossover point crossing over to a large mid range tweeter horn. At the time one reason sited for this was in orchestra music 1/2 the music power was below 500 hz and half was above 500 hz.
ahhhh yes, the good ole days
TRUE, very true. One of my audio buddies does that exactly, and with good results.
The John Hilliard system was comprised of 2 Altec 15" (per side) mounted in a large, almost infinte baffle (either side of a chimney) with an Altec Sectoral horn, if I recall correctly, and crossed at 500Hz.
TRUE, very true. One of my audio buddies does that exactly, and with good results.
The John Hilliard system was comprised of 2 Altec 15" (per side) mounted in a large, almost infinte baffle (either side of a chimney) with an Altec Sectoral horn, if I recall correctly, and crossed at 500Hz.
coffee time
Greetings !
To answer your questions:
1) Yes, it's the actual electronic network slope: 48/db/octave. The acoustical resulting slope is even steeper, and could be asymetrical, but is of little concern to be personaly, because it's so far down in level that the aberations are small compared to the room's signature.(Even though my room is heavily damped against reflections).
2) Yes, all drivers except the sub-bass are time aligned.
And to review, the x-overs are @ 60Hz, 250Hz, and 3500Hz. It sounds really good, but the only thing I'd like to experiment with is adding some additional subs that carry a slightly different range, as per the Geddes article I read about using multiple subs. The deep, deep bass will still (obviously) be produced by the infinite baffle, and I'd like to add some bass units that might carry up to around 150hz, where I can replace the "stub horn" with an actual horn for the lower mid range.
happy listening !
Greetings !
To answer your questions:
1) Yes, it's the actual electronic network slope: 48/db/octave. The acoustical resulting slope is even steeper, and could be asymetrical, but is of little concern to be personaly, because it's so far down in level that the aberations are small compared to the room's signature.(Even though my room is heavily damped against reflections).
2) Yes, all drivers except the sub-bass are time aligned.
And to review, the x-overs are @ 60Hz, 250Hz, and 3500Hz. It sounds really good, but the only thing I'd like to experiment with is adding some additional subs that carry a slightly different range, as per the Geddes article I read about using multiple subs. The deep, deep bass will still (obviously) be produced by the infinite baffle, and I'd like to add some bass units that might carry up to around 150hz, where I can replace the "stub horn" with an actual horn for the lower mid range.
happy listening !
Attachments
It may very well be the case.
Do you have any link to your two way building project ? Thanks.
I haven't seen it. In a few days i'll have more spare time for my loudspeaker musings.
Center of the woofer 65cm/85cm/100cm respectively.
I haven't done measurements by puting the loudspeaker on the back in the middle of the room and with mic above it because xover frequencies of the loudspeakers that i made so far were always above 1KHz.
In a few days, when exams pass, i'll start measuring my three way box like that because my bass/mid xover point will be at around 300-400Hz. I'll se what will happen to the dip.
Thanks Michael.
Have you considered some baffle step compensation ? Saddle that forms from 200Hz to 800Hz might well be because of baffle step effect, taking baffle width into consideration that is about 15cm-17cm (6-6 3/4") by my rough assessment. I'd try to put two pieces of plywood to sides of the box and measure it just to see what happens.
Distortion looks awesome btw.
I haven't done measurements by puting the loudspeaker on the back in the middle of the room and with mic above it because xover frequencies of the loudspeakers that i made so far were always above 1KHz.
In a few days, when exams pass, i'll start measuring my three way box like that because my bass/mid xover point will be at around 300-400Hz. I'll se what will happen to the dip.
Thanks Michael.
Have you considered some baffle step compensation ? Saddle that forms from 200Hz to 800Hz might well be because of baffle step effect, taking baffle width into consideration that is about 15cm-17cm (6-6 3/4") by my rough assessment. I'd try to put two pieces of plywood to sides of the box and measure it just to see what happens.
Distortion looks awesome btw.
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Scott, thanks. You have an excellent system! Someday, I hope, I will be able to afford the space for all-horn stereo setup. For now I'll go with small desktop speakers
I mulled over different choices of crossover topology for my FAST, and I think I'm going to go with the simplest one: first-order passive line level crossover somewhere at 200-300 Hz. Four tiny caps, less than 1$ in total. Even if I screw it up, it won't be a big deal. A wavelength of the 300Hz wave is pretty big so phase mismatch between drivers is not going to be a big issue even with a flat, vertical baffle. And I'm going to use FIR equalization on my PC to correct the frequency response anyway. Even if below XO point the response won't sum flat due to fullranger, FIR filters are going to correct that while preserving the clean impulse response.
Hi Michael,
It's harder to tune a speaker with baffle step compensation but sounds
way better in bass. Your tweeter filter could be better though. It's
receiving power below XO point for no reason and that means distortion.
because real question is "sensitive to what?"
in an ideal world?
to me is looks rather like two-way = three problems, three-way = six problems
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