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Multi-Way Conventional loudspeakers with crossovers

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Old 15th January 2013, 04:14 AM   #771
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I wondered the same thing.

Apparently the individual cells become 'sources' themselves and thus the number of cells aids dispersion of the sound over the near and far field in a way the whole shell would not.

My issue with papier mache will be soggyness if I dont use card as the initial inside layer. Will start today on a rough pair - one with card liner and one of paper only.

pix to follow
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Old 15th January 2013, 05:02 AM   #772
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I've done this and no, it won't perform the same in the HF plus there's a difference between whether you clone the shell of a tar or non tar filled version as to whether it will perform the same down low. In concept, the WE/Altec 329A horn is ~ the shell of a 1005B, so gives some idea of what to expect, i.e. a traditional rising on axis response like the 511, 811 horns.

I chose the wave guide [conical] shape of the tar filled and once I got it figured out somewhat, it convinced me that this was the way to get high SQ out of a compression horn, though at the cost of it needing to be a lot bigger for the same LF corner, i.e. a ~1803 size to get a solid 500 Hz using an 802D.

This hurt the HF output too much due to the strong mouth reflections back to the throat, so wound up with an ugly foam horn extension initially and ultimately a very large round-over extension that made the LF/HF horn c-t-c spacing audibly unacceptable at my ~16 ft listening distance.

To get the 'full' mids of the big horns and the HF of the 'small' horns, I finally 'settled' for dual stacked 511s with one rolled off. Once damped, I found I liked this better in my app than an EQ’d multi-cell, though not as much as the huge WG. ‘BIB’ rules!

All things considered then, following the profile of a non tar fill 1505 and limiting it to 4-5 kHz seems worth trying and with today’s digital delay, placing a small super tweeter horn inside to cover the top two octaves could make for an impressive combo.

Better yet, an 1803 tar filled shell with super tweeter horn.

GM
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Old 15th January 2013, 05:24 AM   #773
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Morning GM. So do you not believe the papier mache/card endeavour will work? Or are you just saying you prefer sectoral to multicell?
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Old 15th January 2013, 05:45 AM   #774
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A late night here.

I see no reason why not assuming you plan to make a multi-cell and not just a shell as I did, otherwise you'll have the same set of trade-offs to deal with.

WRT multi-cell Vs sectoral, it mostly comes down to how wide a 'sweet spot' and HF response is desired, so is very dependent on the room, system and of course, personal preference.

Personally, the sectoral is at the bottom of my list for high SQ as there's no way to get around its inherent 'horniness' without using a high enough XO point to turn it into basically a HF WG.

GM
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Old 15th January 2013, 11:57 AM   #775
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REALLY stupid question.

Vol pot goes inline with the incoming line signal then lpads on the outgoing speaker level signal? Combined stereo pot/lpad ok for both applications?
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Old 15th January 2013, 02:03 PM   #776
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scrap the last bit about stereo lpads.......as per Pano's words above.

Question. When looking for pot for ACA ZM said "btw - if you're feeding just one way with ACA , L-pads are redundant (and bad for sound) , having pot in front of ACA" and "if you have pot in front of ACA , you don't need attenuation right in front of driver. Any sort of L-padding ( variable or fixed ) will kill the grunt. Try , listen and then decide"

I was confused about having vol pot AND Lpad and now more so
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Old 15th January 2013, 03:21 PM   #777
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Assuming you have two identical amps feeding horn and woofer, you of course need some way of adjusting levels to get the two to match. This can be done before or after amp, or both. You could level it after amp and all is good, if you have identical gain structure feeding both high and low. If you have mismatched amps and, as a result, mismatched gain, then you need to be able to adjust the amps accordingly. This would be done with pot on front. I think either will work fine, but I do get the idea of having it adjusted before the amps get involved.
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Old 15th January 2013, 03:27 PM   #778
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I'm with you on that buzz.

Quote:
Originally Posted by Pano View Post
...Horns are very efficient. That means all the hiss, hum, buzz, rizz, etc. that you don't notice on normal speakers will be plenty obvious on the horns. Dropping the horn's level 6-12dB will get the amp's output up out of the dirt. Yes, you'll need more power, but that's rarely a problem in domestic settings.
I think I get Pano's statement above. reducing the ACA speaker level output via Lpad's allows more volume to be used getting the amp into the clean fresh air of up to 5W.

As its a Nelson Pass SE will it be dirty low down? (not not like that )
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Old 15th January 2013, 03:49 PM   #779
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Don't forget that all important FW. With horns, I doubt you will see much more than that on any regular basis, but I do understand his thinking.
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Old 15th January 2013, 05:46 PM   #780
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Yeah and that all important FW is fro ma table on a vineyard in California.

I hate that FW.....

I got this pot: 500K Tocos Cosmos RV24 Stereo Potentiometer Hifi Collective over the Alps blue beauty and lesser than the Nobles & TKD's

I'm gonna cut card sides x 4 tomorrow. 1 will let me cut paper to shape and then will join the others to form the basis of a horn. Papier Mache will fill the voide from front to rear lip left by the curve - thats the plan anyhoo

The paper will be a build up of similar shapes getting smaller so fill the void leaving the ends a couple of thicknesses but more in the deeper middle - again, thats the plan anyhoo
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