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Multi-Way Conventional loudspeakers with crossovers

Scanspeak 23w4557 crossover point
Scanspeak 23w4557 crossover point
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Old 8th January 2020, 09:23 AM   #1
Ugg10 is online now Ugg10  United Kingdom
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Default Scanspeak 23w4557 crossover point

Looking at the Scanspeak 23w4457T02.

https://www.scan-speak.dk/datasheet/pdf/23w-4557t02.pdf

Quick calculation seems to suggest that in a 1cuft (28l) sealed box it can provide an F3 of 32hz and an f10 of just below 20hz and QTC of 0.76 which is very appealing for the bass driver on a 3 way. Ok, it is not cheap but - you can't take it with you !

So, looking at the FR plot it seems quite well behaved up to 1khz when it start to break up.

I understand this driver is not very sensitive (understatement) but will be using an active crossover and separate power amps for each driver so this should not be much of a problem.

Looking at using this with a 5" or possibly 6" mid cone driver in a separate sealed enclosure (favourites are SB MR13P-8 or if budget allows the Scanspeak 12MU).

So the questions is - has anyone used this and can comment on performance and secondly what is the highest you would cross over to the mid, currently looking at around 300-400hz LR2 ideally, would that be OK ?

For completeness, my alternative is the 22w8857 in a 42l BR tuned to 28hz which seems to have a similar break up pattern and has been used upto 750hz with a 2" mid dome (Paul K Cantilena). This gives a similar F3 performance but sharper low roll off compared to the 23W but in a much bigger and ported box (I would prefer the sealed box if it can work).

https://www.scan-speak.dk/datasheet/pdf/22w-8857t00.pdf

Thanks in advance for replies, much appreciated.
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Old 8th January 2020, 09:54 AM   #2
coolnose is online now coolnose  Europe
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A friend of mine uses them together with a small 15W/R29 2-way in a full active system, I could ask him about the X-over later today if you wish. I am not mistaken using ICEPower ASP1000 amps for each 23W. Pretty impressive I must say....
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Old 8th January 2020, 10:05 AM   #3
Ugg10 is online now Ugg10  United Kingdom
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Many thanks, much appreciated if you could. Any links to the build would also be great if there are any.
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Old 8th January 2020, 10:24 AM   #4
coolnose is online now coolnose  Europe
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Totally a "offline" build.... but will revert with X-over data for the 23W
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Old 8th January 2020, 10:53 AM   #5
waxx is offline waxx  Belgium
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It also depends on the crossover slope, a 4th order could be arround 700hz, while a first order would have to stay under 400 i think. But best is to sim it, even with only the curve from the spec sheet you can find this out using the graphic capture function of programs like VirtualCad. it will not be precise, but gives you an ID what is the best region to start.
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Old 8th January 2020, 11:49 AM   #6
coolnose is online now coolnose  Europe
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Quick update;

"Mating a 23W that is designed to go wayyy down with a smallish 12cm is not recommended (I gave you the "very polite version"), 23W good for up to 300 Hz if EQing the cone break-up at 1.2kHz . IF you insist my friend suggests to go with a 300 Hz, LR 4th order, 24dB/oct as a starting point that should "work" +/- ...

Other than that you are on your own.... And I can't help (not that I don't want to, it' just over my head and not my domain....) I told you what he mated them with though.
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Old 8th January 2020, 01:36 PM   #7
Ugg10 is online now Ugg10  United Kingdom
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Many thanks both for the replies, much appreciated. Please pass on my thanks also to your friend @coolnose and point taken on the smaller mids, will look into 6-6.5" ones, do you know which version of the 15W he used and with what tweeter.


I have done a couple of sims using Boxsim 2.0 with crossovers at around 350hz both LR2 and LR4 with the MR13P and will try and post results late this evening.
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Old 8th January 2020, 10:21 PM   #8
Ugg10 is online now Ugg10  United Kingdom
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So here's a few sims, thoughts please.

1) WINISD comparison of 23W Closed in 28l Qtc = .76 9 (Blue) vs 22W BR in 42l tuned to 28hz (Green) - 23W Closed looks very good and needs no low roll of at 60W (power of my amp, too small but Ok for a start), 22W needs a 2nd order highpass at 25hz to keep it under xmax plus a 3inch port to keep velocity below 20m/s.

2) Boxsim 2.0 active sims for 23W closed LR2 and LR4 for comparison with SB MR13P-8 and SB 26ADC.

Baffle 95x30cm - 23W @ 53cm, 13P @ 73cm, 26ADC @ 86cm all on centreline i.e. small floor stander that may have a divider half way up to produce 28L bass cavity.

23W - 28L moderate stuffing, simmed with 2xFs upwards (hence smooth bass roll off), xover at 300hz

13P - 3lL moderate stuffing, xover set using optimiser - LR2 = 425/1900, LR4 = 330/2440hz

26ADC - 2700hz crossover
(All data from datasheets using Vituix cad trace)
Only other controls are delays set on 13P and 26ADC with optimiser, no smoothing using parametric filters i.e. 13P surround 1500hz wiggle is still there.

Graphs show individual frequency response/crossover, off axis spread 0-30 degs, phase.

All comments/observations welcome.
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Old 10th January 2020, 09:36 AM   #9
Ugg10 is online now Ugg10  United Kingdom
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Edit - just noticed that in the WinISD plot I have incorrectly labeled (22W4557) the 23W4457, just to confirm the Blue line is the 23W4557 in a 28L sealed box, the green line 22W BR is the 22W8857 in a 42l Vented box.
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