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Can someone explain how this Linkwitz Transform works?
Can someone explain how this Linkwitz Transform works?
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Old 19th October 2019, 10:02 AM   #21
3rutu5 is offline 3rutu5  Australia
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is there anything passive one can do to lift that low end?

I've been looking around and some of the audio\bt boards can be customised with their EQ settings, which i didnt know was possible, but looks like the change would be applied to all channels, which isnt something i would want to do.
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Old 19th October 2019, 10:24 AM   #22
picowallspeaker is offline picowallspeaker  Italy
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Quote:
Originally Posted by 5th element View Post
That article ends with these words:
Quote:
As is quite obvious, the differences are small, and in the greater scheme of things can be ignored. The room will cause far greater errors than the circuit.
What errors?

IDK...the sound propagates from the sources at Mach1 velocity, bounces to the walls and extinguishes, arrives to the ears...the brain does some calculations
What errors?
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Old 19th October 2019, 10:25 AM   #23
picowallspeaker is offline picowallspeaker  Italy
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Quote:
Originally Posted by 3rutu5 View Post
is there anything passive one can do to lift that low end?
Just use a huge subwoofer driver that overwhelms the satellites
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Old 19th October 2019, 10:35 AM   #24
scottjoplin is offline scottjoplin  Wales
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There are passive tone controls which work by cutting rather than boosting but if you have enough gain in the amplifier amount to the same thing.

Also, this very simple circuit will give you a small apparent boost at lower frequencies Baffle Step Compensation

Rod Elliott's site is somewhere you should explore I think
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Old 19th October 2019, 10:42 AM   #25
3rutu5 is offline 3rutu5  Australia
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Cheers, I've used a.BSC a few times and it was quite good, just not sure if it will provide the little bass note in a box half the size of what I'm using currently. I will have a bit of a read through that site though
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Old 19th October 2019, 10:47 AM   #26
scottjoplin is offline scottjoplin  Wales
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Equalisers
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Old 21st October 2019, 09:06 PM   #27
5th element is offline 5th element  United Kingdom
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Quote:
Originally Posted by picowallspeaker View Post
That article ends with these words:

What errors?

IDK...the sound propagates from the sources at Mach1 velocity, bounces to the walls and extinguishes, arrives to the ears...the brain does some calculations
What errors?
He's talking about the circuits measured response Vs the simulation. Saying there's only very little error between the two and as the majority of the error is at frequencies below which we can hear it doesn't really matter.

No doubt the deviation is caused by capacitor tolerances.
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Old 22nd October 2019, 08:36 AM   #28
chris661 is offline chris661  United Kingdom
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Quote:
Originally Posted by 5th element View Post
This is completely missing the point.
No, I think you're missing my point.

My point is this:

At low frequencies, a speaker in a room will need fairly large EQ adjustments in order to produce a flat response at the listening position.

Your method seems to be be to use a Linkwitz Transform to make the speaker flat, and then apply more EQ to sort out what the room is doing.

My method is to treat the room and speaker as one, and EQ the result.

We end up with the same thing (flat response) at the listening position, but your method means you've got an stage with 6-10dB of boost when there's a fair possibility that's going to be cut down by the next EQ in the chain.


Here are the measurements:

Simulated:
Click the image to open in full size.

Measured at the listening position:
Click the image to open in full size.


I'm sure you can imagine what my EQ curve looks like - no positive gain is required to get a flat response.

So, if I did happen to apply a Linkwitz Transform to get flat to 20Hz, I'd end up having to make even larger cuts at the "room EQ" stage to get back down to flat.


In conclusion, instead of saying "oh yes, it's a sealed box, it'll need a Linkwitz Transform", I'd suggest that the speaker should be measured in-room before any EQ (Linkwitz Transform or otherwise) is applied.

Chris
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Old 22nd October 2019, 08:54 AM   #29
freddi is offline freddi  United States
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Can someone explain how this Linkwitz Transform works?
re: passive, "3rd order" closed boxes using a series capacitor can be useful as long as the amplifier driving impedance is low and their "boost" comes from a drop in impedance where its normally risen somewhat above Re.

And of course assisted 6th order vented boxes make good use of active EQ.

Click the image to open in full size.
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Old 22nd October 2019, 03:41 PM   #30
xrk971 is online now xrk971  United States
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Can someone explain how this Linkwitz Transform works?
Just buy an inexpensive 10in active sub with adjustable crossover. I got a Polk PSW10 free shipping from Amazon and it integrates easily and sounds very nice. Super low hassle if you don't want to deal with all of this. This used to be only $100, but now seems like it is $150. However, it's very well made and probably worth it. No way you are going to do it yourself an nicely finished box, panel connectors, amp, crossover, driver, port tube, rubber feet, power cord, and grill cover for anywhere close to this price. But if the goal is the learning journey - then by all means DIY.

https://www.amazon.com/Polk-Audio-PS...dp/B0002KVQBA/
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Last edited by xrk971; 22nd October 2019 at 03:44 PM.
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