My humble 3 Amp system :
2 x Bookshelf : Woofer 6" 80W (50Hz to 5000Hz) + Tweeter 20W (1500Hz to 30K)
2 x Sub 8" 120W (25Hz to 1200Hz)
Linkwitz-Riley 3-Way 4th Order filter (24dB/Oct)
BASS: 20Hz~250Hz MID: 120Hz~4500Hz TREBLE: 2500Hz~30K
And that's my question : Is it Ok those overlapping frequencies ? (assuming I could equalize the high SPL at those frequencies)
Thanks.
2 x Bookshelf : Woofer 6" 80W (50Hz to 5000Hz) + Tweeter 20W (1500Hz to 30K)
2 x Sub 8" 120W (25Hz to 1200Hz)
Linkwitz-Riley 3-Way 4th Order filter (24dB/Oct)
BASS: 20Hz~250Hz MID: 120Hz~4500Hz TREBLE: 2500Hz~30K
And that's my question : Is it Ok those overlapping frequencies ? (assuming I could equalize the high SPL at those frequencies)
Thanks.
1) Smooth transitions (you see, a 24dB/Oct filter is very steep)
2) Weakness compesation : All the drivers have already overlapping freq response....I'm just taking advantage of that.
They can help each other to overcome deficiencies. For example, even though the woofers can reach 5kHz with good gain, the sound lack of "shininess" above 3kHz, the tweeters can help on that.
But the tweeters cannot sustain that freq range alone (only 20Watts)...but they can contribute in brightness. Of course above 5K they take all the load alone.
It's not an expensive set of drivers...so let's make more with what we got.
You are right that a 6" woofer will not be its best at 5kHz. It is not the usual way to overlap like this but it is good you are trying these things. Maybe you need a tweeter that is better at handling down to 2kHz?
No, it's not.
Especially with high order XO.
You will not get the smooth transition that you want.
These are huge overlaps, nearly 1 octave at every step.
There will be significant peaks where the overlap occurs and also most importantly huge dips in the impedance of the speaker.
The phase will also be all over the place but to me the impedance is the major factor.
Why LR4? With good drivers most often 2nd order or even better 1st order will do just fine.
Model your XO in XSim / Basta and see what happens.
Thank all you guys !
I'm not an Audio expert (just an ordinary electrical engineer)...but :
Doesn't Linkwitz-Riley 4th order filter keep 360º shift throughout range ?
So...I would just need all-pass delays to re-match two ways (like mid and treble)...right ?
About peaks and dips...well, you can call me stupid but...isn't just a matter of equalization ?
PS.: here I'm focusing on mid-treble transition...since I'm not a bass-head and I coudn't care less for under 250Hz frequencies (they just need to be there).
Thanks.
I'm not an Audio expert (just an ordinary electrical engineer)...but :
Doesn't Linkwitz-Riley 4th order filter keep 360º shift throughout range ?
So...I would just need all-pass delays to re-match two ways (like mid and treble)...right ?
About peaks and dips...well, you can call me stupid but...isn't just a matter of equalization ?
PS.: here I'm focusing on mid-treble transition...since I'm not a bass-head and I coudn't care less for under 250Hz frequencies (they just need to be there).
Thanks.
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Simulation is your friend:
Use 'ideal' driver model, baffle dimension and just apply your filters under Virtuix cad ( or another software).
It'll gives you trends, then you'll have to take into account the 'real' behavior of your driver to have an idea of what to expect.
I would not expect an eq to be able to solve issues related to physical issues though ( iow: if there is destructive interference for one or more drivers because of their location on baffle an eq won't solve the issue).
Use 'ideal' driver model, baffle dimension and just apply your filters under Virtuix cad ( or another software).
It'll gives you trends, then you'll have to take into account the 'real' behavior of your driver to have an idea of what to expect.
I would not expect an eq to be able to solve issues related to physical issues though ( iow: if there is destructive interference for one or more drivers because of their location on baffle an eq won't solve the issue).
More details about your system would be nice.
You say its a 3 Amp, so its active 3-way XO, yes?
Which drivers you have?
Whats the position and distance of bookshelf and sub cabinets?
In general, overlapping XO frequencies like this is not usual practice and it can hardly make your drivers any better, if thats your goal.
Overlapping can give uneven frequency response. Also, distance between drivers must be less than half of the wavelenght of overlapping frequencies, othervise there will be problems with directivity and comb filtering.
If you want smoother transition, use 6dB/oct between bass and mid, but without overlapping.
For other, 12/18 dB slope combination is often used for bookshelfs with good results. So, try 12db/ for mid and 18dB/oct for HF (usually with with reversed HF polarity), also without overlapping and with XO between 2,5 and 3,5kHz for 6in midbass size.
You say its a 3 Amp, so its active 3-way XO, yes?
Which drivers you have?
Whats the position and distance of bookshelf and sub cabinets?
In general, overlapping XO frequencies like this is not usual practice and it can hardly make your drivers any better, if thats your goal.
Overlapping can give uneven frequency response. Also, distance between drivers must be less than half of the wavelenght of overlapping frequencies, othervise there will be problems with directivity and comb filtering.
If you want smoother transition, use 6dB/oct between bass and mid, but without overlapping.
For other, 12/18 dB slope combination is often used for bookshelfs with good results. So, try 12db/ for mid and 18dB/oct for HF (usually with with reversed HF polarity), also without overlapping and with XO between 2,5 and 3,5kHz for 6in midbass size.
So?
No.
Peaks - yes, kind of...
Dips - no! NO!
Before any further thoughts on crossovers, you have too have a dip, dip dive in some crossover simulation software (VituixCad, XSim, ..)
Is the 4th order LR you are referring to the electric filter response, or the acoustic response? If electrical, it wouldn't be uncommon to have quite asymmetric Fc since that might be what is required when combined with the driver's response to get some final acoustic response that is one of the named types (LR, BW, etc.).
The final acoustic response being a named filter type is what you are aiming for, so I wouldn't get too hung up what it takes for electrical filtering to get there. Usually though, you don't need to use an LR24 electrical filter to get an LR24 acoustic response, since the driver already has a natural rolloff that is its own additional "order".
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Very elucidative discussion...thank you people !
More details (as requested) :
Drivers :
Woofers
Tweeters
Subs (link is for reference...I didn't buy there).
Bass and Mid Amps ( Already have one board...ready to purchase the second one)
Treble Amp (not purchased)
LR4 filter (will be customized)
Power supply (not purchased)
Similar boxes (for reference only...it's not that model...but close enough)
All the boxes (subs and bookshelves) are playing right now using an old 5.1 Philips player + small DAC (BTA30pro). A temporary solution, not bad...but there is A LOT of room for improvements...so I'm building a 3-way stereo Amp.
---------------------------
Since the Crossover is under discussion...I will take a time to do more research.
.
More details (as requested) :
Drivers :
Woofers
Tweeters
Subs (link is for reference...I didn't buy there).
Bass and Mid Amps ( Already have one board...ready to purchase the second one)
Treble Amp (not purchased)
LR4 filter (will be customized)
Power supply (not purchased)
Similar boxes (for reference only...it's not that model...but close enough)
All the boxes (subs and bookshelves) are playing right now using an old 5.1 Philips player + small DAC (BTA30pro). A temporary solution, not bad...but there is A LOT of room for improvements...so I'm building a 3-way stereo Amp.
---------------------------
Since the Crossover is under discussion...I will take a time to do more research.
.
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