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Old 29th September 2013, 03:02 PM   #11
AllenB is offline AllenB  Australia
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1dB may not seem to do much on some systems but when a system is good, it can make a fair difference. The octave below 500Hz is quite important for feeling the weight of certain sources such as voices.

It looks as if this region may be crossing the 'baffle step' though and this can complicate matters as you'd need to go through it in the time domain and at various angles to make sure what you see is what you hear.

As you get it balanced above and below 500Hz the speakers may sound a little more dull, but press on and get it right and you'll probably want to keep it that way.


By the way, have you thought about a first order shunt highpass filter?
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Old 29th September 2013, 06:49 PM   #12
tinitus is offline tinitus  Europe
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since you know how to handle a DSP ...
why not ad another woofer, and try real 3way
with the sub crossed lower

or do real 3way, and use EQ to get the woofer down
it might not be so good for loud SPL, and strugle with the EQ
but that's just a choice
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Old 29th September 2013, 06:56 PM   #13
tinitus is offline tinitus  Europe
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btw, why can't the DSP take care of the 'missing midbass'

ahh, sorry, you only have DSP on low woofer
and use tube amps for the top
tricky stuff

adding another 5", having two in series

and btw, tube amps can do weird things when presented to impedance variations from a passive crossover
maybe that is your real problem

or you could have phase problems around the missing frequency ... or both
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Old 29th September 2013, 07:03 PM   #14
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Passive radiators work at low frequencies. As a speaker engineer, to be honest I cannot directly say why it wouldn't work, but a lot of intuition alarm bells ring in my mind. I have only ever seen Electro-Voice implement a vented mid-range...a passive radiator would be a whole other layer of difficulties. Plus your rolloff will be so much faster, and excursion at low frequencies uncontrolled...you'd have to totally rework your crossover. My educated guess is you will do a lot of work and suffer for not great results.

I might suggest instead a small passive shelf filter for the upper section? Like a 1-2 dB step just with a couple of resistors and a capacitor.
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Old 29th September 2013, 08:02 PM   #15
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Thanks guys.

Looks like a shelf for the 500 Hz + region is going to work. First few listens aren't bad.

Bill
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Old 29th September 2013, 08:47 PM   #16
sreten is offline sreten  United Kingdom
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Hi,

PR's don't do midrange. Baffle step can be addressed by
a passive filter pre power amp and is a lot more than 1dB.

In a 3 way the slope of the bass can be manipulated to
provide the BSC for the mid unit. Seems to me there
is a fair amount of waffle and no hard details here.

rgds, sreten.
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Old 29th September 2013, 08:58 PM   #17
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by sreten View Post
Hi,

PR's don't do midrange.
no, it won't

but if the problem is too early rolloff in closed box, 'porting' might help
could be like rolling off closer to 100hz, instead of 200hz
just random number, ofcourse

but I have always suggested to be very cautious porting a 2way when using subs
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Old 29th September 2013, 09:12 PM   #18
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by tinitus View Post
no, it won't

but if the problem is too early rolloff in closed box, 'porting' might help
could be like rolling off closer to 100hz, instead of 200hz
just random number, ofcourse

but I have always suggested to be very cautious porting a 2way when using subs
Hi,

I don't disagree, but I can't see the relevance to good 3 way design.

Here we've got general details and no specifics, like why a notch
filter is really better than a high pass, giving an elliptic function.

Its used much more often on low pass than high pass due
to inevitable distortion issues for the high pass variant.

rgds, sreten.
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Last edited by sreten; 29th September 2013 at 09:16 PM.
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Old 29th September 2013, 09:24 PM   #19
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by Cousin Billy View Post

The natural roll-off of the midrange (9 liter volume)...
with closed 9liter calculation does in fact show a very nice smooth rolloff at 100hz

around 5liter seem to gives 1db more output around 150hz

not something I would consider for a final design
but you could still try in the one you have playing
stuffing with closed cell foam might do it

I still suspect your worst problem right now might come from a phase problem
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Old 6th October 2013, 10:34 AM   #20
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Tinitus

Please help. Where would my phase problem come from?.

I am using a first order crossover, with a notch to help the low end roll-off.
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