- Thread Starter
- #21
Great thanks
-
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Crossover / Bandpass for LS50 "Bass Stands" and HT/SYN
- Thread starter john61ct
- Start date
- Thread Starter
- #22
My current thinking using Wiim Amp Ultra for crossover / speaker correction maybe Roomfit
Might not end up using the Outlaw ICBM. Was thinking could get a second one and daisy chain to get bandpass for the basstands (say that ten times fast :-O
but that's set aside for now
Might not end up using the Outlaw ICBM. Was thinking could get a second one and daisy chain to get bandpass for the basstands (say that ten times fast :-O
but that's set aside for now
- Thread Starter
- #23
Picked up a NOS Alesis 3632 very cheap, just for the Limiter functionality to protect the LS50s when testing/measuring. Supposed to be a much better quality design and implementation than the ol' 3630
Looking at using Wiim Amp Ultra PEQ for all frequency filtering on the LS50s, emulating crossover since I need to keep the LPF output to the basstands in stereo.
Assuming the basstands are good SQ right up into midrange, do you think there would be any advantage to going past say, 300Hz for the LS50 HPF ?
If 120Hz were high enough, I'm guessing a true mirror crossover using the ICBM would be the better tool.
Since these will be co-located with the LS50s I'd say 300Hz or higher to keep the LS50 mids (waveguides) as stationary as possible. Assuming the chosen drivers are up for it.
Sokel
Grand Contributor
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If subs and mains are tight together I would start low, 120-140Hz and go upwards while measuring.
Thing is that going higher you have to have anechoic data.
A good idea is to simulate everything in Vituixcad for starters.
- Thread Starter
- #26
How much higher should I be considering / testing ?
I haven't selected the drivers yet, might end up doing one pair of cubes optimised for mid-bass + low-midrange, then another stereo pair to get down to 60-80Hz.
My understanding is below that should NOT be stereo, a brick wall filter should transition over to mono-only subs. I think the ICBM would work well for that...
- Thread Starter
- #27
Could you explain why, and/or link to a HowTo?
I was hoping the Wiim Ultra toolset, coupled with say REW + UMIK, would get me a good way along...
- Thread Starter
- #28
Do you mean location? The stereo basstands are literally speaker stands for the LS50s, main thread in the OP.
They are not really "subs" here, I'm using that moniker for the separate unit(s) serving mono below 80Hz, if I find out I really need that, once the basstands are tuned in
Sokel
Grand Contributor
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Two great threads:
Link1
Link2
First one is a cornerstone and will give you a great idea about the challenges.
Good news is that Vituixcad and REW are both free (and amazing) and the former can let you see what your end result will be while sitting on your chair.
But!
The result will be as good as the data you'll insert to it.
So, start reading, it's a steep learning curve but can be fun!
Link1
Link2
First one is a cornerstone and will give you a great idea about the challenges.
Good news is that Vituixcad and REW are both free (and amazing) and the former can let you see what your end result will be while sitting on your chair.
But!
The result will be as good as the data you'll insert to it.
So, start reading, it's a steep learning curve but can be fun!
Based on the distortion data I would think 150Hz 2nd order is good enough for most people, if you really plan to crank them then 200Hz would be ok. You can simply test them out without subs at these crossovers and see if they sound strained at all at your loudest listening levels, I would cross them as low as possible to retain the point source into the bass frequencies though.
- Thread Starter
- #32
That last is not fixed, the real point of the project is to enable / determine highest possible "safe" SPL of this model, including in a mobile / outdoor context.
> I would cross them as low as possible to retain the point source into the bass frequencies though.
Sorry I do not understand, could you explain or rephrase? The basstands are in the same stereo locations, if you're talking about imaging / localization, and their range will stop at 70-80Hz if true subwoofer(s) are needed in mono.
kemmler3D
Master Contributor
The limiting factor should be the lowest frequency coming from the LS50 and the maximum SPL it can produce there.
You should not cross the LS50 higher than about 200-300 as it's only omnidirectional below that range.
If you check the review, the distortion goes over 100% at 96dB even at 200hz so you can't really go beyond that regardless of what kind of bass stand you add.
The distortion situation does not improve until after it crosses to the tweeter, so that's pretty much your limit any way you slice it.
You can reduce distortion below 200hz or so for cleaner bass, but this speaker has limits even in the midrange so you won't be getting PA levels from it either way.
- Thread Starter
- #34
I am not looking to get SPL beyond a safe and clean level, just within those boundaries. Nothing to do with PA?
Is that what gives it the wide dispersion?
phoenixdogfan
Major Contributor
Actually distortion at 200 hz is at 60 db while signal is at 96 db. Thus distortion 36 db below signal which at 200 hz is 1.77%. So as long as you high pass the LS 50's with something 12 db octave or greater above 150 hz, the THD should be much improved, provided you have two low distortion subs placed in close proximity to the LS 50's.
The real issue is the IMD as seen on Erin's multitone. It's over -30 even with a high pass at 80 hz, and it's far more audible than the THD. It's really the IMD caused by the coincident driver that's both the crowning achievement and club foot of the speaker. And I agree, you still won't be able to play that 5' woofer much over 100db no matter how high it's crossed over.
- Thread Starter
- #36
Thanks much!
Above 150 hz, yes, but I'm asking at what higher point should I not bother testing?
"12 dB per octave" is about slope not xover point correct? Way too gentle compared to what I was planning
Based on a 150 Hz cutoff frequency and a 12 dB/octave slope, there will still be a lot of attenuation into 600Hz ranges.
I was thinking lots steeper would be necessary, more brick wall ish.
Above 150 hz, yes, but I'm asking at what higher point should I not bother testing?
"12 dB per octave" is about slope not xover point correct? Way too gentle compared to what I was planning
Based on a 150 Hz cutoff frequency and a 12 dB/octave slope, there will still be a lot of attenuation into 600Hz ranges.
I was thinking lots steeper would be necessary, more brick wall ish.
phoenixdogfan
Major Contributor
The filter is a high pass on the LS 50 Metas, so it will attenuate below the crossover frequency only. The Low pass on the sub will attenuate their output above the crossover point, and since there will be a great deal of natural roll off above 150 hz on any sub anyway, it won't be necessary to do more than 24 db/octave at most. Probably a L-R with 24 db octave on both legs will take care of everything as long as the subs are close (like 24 inches) from the mains.
As for distortion, people might want to read this post in Axiom Audio before they consider spending thousands to chase the lowest distortion speakers:
How Much Distortion Can We Hear With Music?
How much distortion can we hear with music? An experimental study at Axiom.
www.axiomaudio.com
Even so, I do believe the biggest issue with the Metas is not their harmonic distortion in the bass, but rather their high levels of IMD carrying all the way into the midrange (1000 hz and up) when played at higher levels. That kind of distortion is almost certainly audible, and the ear is especially sensitive to it in the midrange. See Erin's review and you'll know what I'm referring to.
- Thread Starter
- #38
Aha thanks for furthering my learning!
Just a reminder, not talking about "subs" wrt these stereo basstands, yes they are colocated with the LS60s, since they are acting as their stands
If I do decide I need (true mono) sub(s) the basstands will be high passed at the sub's starting point, likely 70-80Hz
The Outlaw ICBM I plan to use for that crossover only does Butterworth 12 dB/octave slope for the HPF, but for the LPF gives the option of going to 36 dB/octave.
Is there anything that can be done to ameliorate that, other than lowering the volume?
Just a reminder, not talking about "subs" wrt these stereo basstands, yes they are colocated with the LS60s, since they are acting as their stands
If I do decide I need (true mono) sub(s) the basstands will be high passed at the sub's starting point, likely 70-80Hz
The Outlaw ICBM I plan to use for that crossover only does Butterworth 12 dB/octave slope for the HPF, but for the LPF gives the option of going to 36 dB/octave.
Is there anything that can be done to ameliorate that, other than lowering the volume?
phoenixdogfan
Major Contributor
Get a speaker with lower IMD, or play the Metas in a smaller room at lower levels is the only thing I can think of. Since the IMD is the result of the woofer-tweeter interacting since they are mounted on the same surface, the only thing that ameliorates it is for the woofer to have have lower excursion which is somewhat achieved by crossing over at higher frequencies, but the issue is inherent in coaxial drivers.
- Thread Starter
- #40
OK thanks.
OG LS50s btw not Meta, likely irrelevant distinction here though.
And they are a given for purpose if these threads, so I guess this IMD issue is just something for me to keep in mind relative to pushing SPL
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