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Multi-Way Conventional loudspeakers with crossovers

Altec 605a duplex crossover upgrade
Altec 605a duplex crossover upgrade
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Old 8th November 2017, 12:37 PM   #41
kaputt is offline kaputt  Germany
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Originally Posted by kaputt View Post
I'll post the measurements later.
Here we go. Measurements were taken with 1 meter distance microphone to baffel so there is some room interaction. All three measurements include the crossover.
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Old 8th November 2017, 02:09 PM   #42
bentoronto is offline bentoronto  Canada
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Altec 605a duplex crossover upgrade
Nicely presented charts.

Wise if kaputt also did measurements at some other points in the room, esp where he/she sits. That's my reference point because it takes the room into account.

Anybody ever ask themselves, "Why must the woofer and the tweeter have the same crossover frequency?" You might ask that question after looking at the kaputt's data.

That's a question folks with DSPs can ask. And that's because only they can answer by trying it.

Or if that concept totally horrifies you, asking "Any benefit by shifting the mutual crossover point a bit one way or the other?"

B.
PS Still waiting to see Pano's posted measurements that are critical of the Behringer DCX2496
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Old 8th November 2017, 04:05 PM   #43
kaputt is offline kaputt  Germany
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There already is some room interaction in there, as I wrote. As the topic was crossovers it would be preferable to have graphs without room reflections.
I'll do a response graph with the microphone in my listening postion (which is more of an area, as I'm quite casual about it ) as I guess there is some value to it in regards of connecting my data to subjective sound impressions I gave.
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Old 8th November 2017, 04:09 PM   #44
kaputt is offline kaputt  Germany
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Anybody ever ask themselves, "Why must the woofer and the tweeter have the same crossover frequency?" You might ask that question after looking at the kaputt's data.
They don't and picking a lowpass with a lower cutoff frequency would have dealt with that bump at 2k. But after all it's so little that I don't care. Changing the graph's smoothing to 1/6 octave fixes that nicely anyways
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Old 9th November 2017, 12:54 AM   #45
Pano is offline Pano  United States
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Altec 605a duplex crossover upgrade
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PS Still waiting to see Pano's posted measurements that are critical of the Behringer DCX2496
I never could find it in the DCX thread. I posted too many times there! But I still have them and can post them again.
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Old 9th November 2017, 12:59 AM   #46
bentoronto is offline bentoronto  Canada
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Altec 605a duplex crossover upgrade
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Originally Posted by Pano View Post
I never could find it in the DCX thread. I posted too many times there! But I still have them and can post them again.
Love to see 'em. Likely to post in the DCX thread? With a link here?

We're all looking forward to the new DIYaudio software with hopefully better search function.

If I can take a minute more promoting DSP, perhaps OP could borrow a DSP* just to experiment and later incorporate test results (crossover parameters, loudness levels, etc) in a passive crossover? No need to buy an extra amp since the other channel can be used for the other driver.

B.
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Last edited by bentoronto; 9th November 2017 at 01:02 AM.
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Old 10th November 2017, 09:29 AM   #47
kaputt is offline kaputt  Germany
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They don't and picking a lowpass with a lower cutoff frequency would have dealt with that bump at 2k.
I changed the 7uF cap in the low pass filter to 9.2uF which flattened the 2k bump.
I'm undecided if I like it better with or without the bump or if I can even tell the difference...
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Old 10th November 2017, 06:39 PM   #48
WBS is offline WBS  United States
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...Anybody ever ask themselves, "Why must the woofer and the tweeter have the same crossover frequency?"
Well, we know that varying the slope can be beneficial. At least Altec thought so. For the 604-8G they designed the crossover with a 12dB/octave slope for the LF and an 18dB slope HF. This would affect how the drivers blend, wouldn't it?
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Old 10th November 2017, 07:40 PM   #49
kaputt is offline kaputt  Germany
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Sure it would. And the other way around it's useful to look at the rolloff of a driver and what filter goes along with that rolloff to make them blend nicely. Maybe a 6dB filer is enough, maybe an 18dB filter is needed.
I general a high frequency driver, depending on the crossover frequency can use a steeper filter for protection and the LF driver a flatter filter as the natural rolloff just needs a little control.
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Old 10th November 2017, 08:29 PM   #50
bentoronto is offline bentoronto  Canada
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Well, we know that varying the slope can be beneficial. At least Altec thought so. For the 604-8G they designed the crossover with a 12dB/octave slope for the LF and an 18dB slope HF.
And maybe it had something to do with the cost of coils! For sure, you want to curb the enthusiasm of the tweeter with a sharp slope; that's more important than keeping some treble from leaking out of the woofer.* But even 18 dB leaves a lot of power going to the tweeter an octave below the crossover point.

I just love using using a 48dB slope Linkwitz-Riley DSP crossover for my 130 Hz crossover*. Inconceivable for Altec to make such a thing passively and vastly more inconceivable for any passive crossover below 400 Hz.

B.
*Opinions vary about everything to do with crossovers. But when you are pretty low in the compass, you need sharp filters to have much impact keeping lows out of the mid-range drivers, etc.
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Last edited by bentoronto; 10th November 2017 at 08:32 PM.
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