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How do you design your own scoops?

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nejten View Drop Down
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    Posted: 31 July 2020 at 1:54pm
Hi everybody

I have been very interested in designing my own speaker cabs/ plans (especially scoops) for quite some time. And I was wondering, how do people come up with designs? What programs/guides are important to learn? I am a complete noob to all of these aspects, so I am very curious for anybodys advice!Smile

Thanks in advance
From small acorns oak trees grow.
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nejten View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nejten Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 2:08pm
This is some info I found on this forum but is does not feel like enough to get me started.:

1.Scoop Chamber Size's

Small chamber     : 185mm - 205mm, upto 44L 
Medium chamber : 205mm - 254 mm, upto 66L
Large chamber     : 254mm ++, 66L and above

Small chamber
Most efficient, huge amount of pressure and throw, needs plenty eq to go really deep, unless 4+ cabs, Should have very good driver control, great for outside or large venues

Medium chamber
Good throw + SPL with efficient drivers, very little EQ to go deep, 2x cabs can go real low, OK driver control with good drivers, great for small/medium/large indoor venues

Large Chamber
Least efficient, Will go very deep with little or no eq, will be loud and deep close up, not as much throw, as above 2x, reduced driver control at high power, best for smaller venues

All depends on driver used, if cab designed properly, length of rear baffle,chamber, expansion rate of cab.

Scoops with larger mouth don't compress air so much, has less throw but smoother sound. 


2.You need to get the chamber size right first, then the throat.

If chamber is too small, all upper bass, no sub.
If chamber is too large, not much SPL, and drivers will blow excursion at low power, especially low BL drivers.

Next, if throat is too tight, larger Vas/qts drivers wont like it.
If throat is too large, or not enough compression at start of horn, you wont get much sub, or the SPL/energy will stay in the box, and not be projected.

If horn is too long, pressure on cone will blow weaker drivers, and lower Xmax drivers also wont like it.

If Horn Mouth isn't large enough, will also cost sub depth.

60-65L chamber (inc driver) , with 700-800cm2 throat, with 200cm Horn, and >=4000cm2 horn mouth will probably sound nice, with every half decent driver on the planet.

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levyte357- View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote levyte357- Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 2:57pm
Originally posted by nejten nejten wrote:

This is some info I found on this forum but is does not feel like enough to get me started.:

1.Scoop Chamber Size's

Small chamber     : 185mm - 205mm, upto 44L 
Medium chamber : 205mm - 254 mm, upto 66L
Large chamber     : 254mm ++, 66L and above

Small chamber
Most efficient, huge amount of pressure and throw, needs plenty eq to go really deep, unless 4+ cabs, Should have very good driver control, great for outside or large venues

Medium chamber
Good throw + SPL with efficient drivers, very little EQ to go deep, 2x cabs can go real low, OK driver control with good drivers, great for small/medium/large indoor venues

Large Chamber
Least efficient, Will go very deep with little or no eq, will be loud and deep close up, not as much throw, as above 2x, reduced driver control at high power, best for smaller venues

All depends on driver used, if cab designed properly, length of rear baffle,chamber, expansion rate of cab.

Scoops with larger mouth don't compress air so much, has less throw but smoother sound. 


2.You need to get the chamber size right first, then the throat.

If chamber is too small, all upper bass, no sub.
If chamber is too large, not much SPL, and drivers will blow excursion at low power, especially low BL drivers.

Next, if throat is too tight, larger Vas/qts drivers wont like it.
If throat is too large, or not enough compression at start of horn, you wont get much sub, or the SPL/energy will stay in the box, and not be projected.

If horn is too long, pressure on cone will blow weaker drivers, and lower Xmax drivers also wont like it.

If Horn Mouth isn't large enough, will also cost sub depth.

60-65L chamber (inc driver) , with 700-800cm2 throat, with 200cm Horn, and >=4000cm2 horn mouth will probably sound nice, with every half decent driver on the planet.



That all looks very familiar, and even looks like my Handwriting.. LOL

Will be monumental task, designing Scoop from scratch, if you don't know how Scoops work.

Suggest you start off by choosing a driver, proven to excel in Scoops.

Then select design, easily modifiable to match your driver. Here is one from Mykey..

https://forum.speakerplans.com/fane-scaled-up_topic74640.html

Originally posted by mykey- mykey- wrote:

Hi Chaps

I had 16 of these around 1989. I had great pleasure with them. They were loaded with the Fane 400 Colossus. Pretty scary when all 16 were running....ask Tre4u2nv LOL

Anyways, I have drawn up 2 versions. One as standard and the other with a double baffle and segmented scoop.

Second version is also slightly deeper, as well as a deeper chamber to receive deeper drivers

Width should be 61cm (24'')... do the cab wider to gain a larger chamber

chamber is 57 litres without the driver

Handle placements and cut off rear for castors is up to you to do

I'm 100% sure that with the Royals and the new monster Fanes these will sing







  EnjoyTongue

When you have learnt what to change in a plan, to tune a Scoop to a driver, or change the Scoop characteristics, then you can talk about drawing up plan from scratch.

You will find Hornresponse does not always sim Rear loaded horns accurately, unless operator can provide HR with all the complex inputs, it needs.


"Gentlemen, you can't fight in here, this is the war room!!".
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Jo bg View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 3:28pm
Hi... if you want to design a scoop  you need to know a little bit about speakers parameters and acoustics.
You now what vas qts xmax refer to in your qupte? If not study T/S parameters and their meaning to understand drivers and how they interact with boxes.
A scoop is a horn, a backloaded one, so you need to read a bit about horn theory...
When you have some theory foundation you could take some proven plan and try to recreate it in hornresp software, to check if you understand how the software relates to physycal plans.
Then you should be ready try your own design... better account for some prototiping too.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nejten Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 3:42pm
Hi Levyte, thanks for your response, it gives a very good idea of every step to design a scoop. Whats your advice on finding a driver suitable for scoops? Can you find one via specific t/s parameters? Also, how do you suggest learning how to change a plan according to your driver, tuning it,...? This seems like a very big challenge for a person like me with little knowledge so please let me know if its too early to start designing cabs etc Tongue  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nejten Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 3:45pm
Hi Jo bg, thanks for the response. I think i am not familiar enough with t/s parameters for starters, so I will do more research on them as well as on horns. Do you have any suggestions for guides or websites that give good information on these topics?
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Post Options Post Options   Thanks (1) Thanks(1)   Quote smitske96 Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 4:46pm
Speakerplans FAQ has info on TS-parameters. What you do with that knowledge takes some more time. 
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Post Options Post Options   Thanks (1) Thanks(1)   Quote levyte357- Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 5:22pm
Originally posted by nejten nejten wrote:

Hi Levyte, thanks for your response, it gives a very good idea of every step to design a scoop. Whats your advice on finding a driver suitable for scoops? Can you find one via specific t/s parameters? Also, how do you suggest learning how to change a plan according to your driver, tuning it,...? This seems like a very big challenge for a person like me with little knowledge so please let me know if its too early to start designing cabs etc Tongue  


You won't be truly designing Scoops, for a few years yet.. LOL

Read Scoop forum, and digest which drivers people love the sound of in Scoops.

You also have to learn, A driver performing awesome in one Scoop, could be very mediocre in another, the reason, the Scoop throat or chamber, is not matched to the driver.

Good starting parameters for Scoop drivers, not set in concrete, just gives an idea.

EBP  : (Fs/Qes) : 100+
Qes  : 0.25 - 0.34
Qts   : 0.21 - 0.30

BL    : 25-27, For smooth, flattish musical sound,
BL    : 30+ For aggressive 40hz peaks, Can withstand higher power, smooths with quantity of cabs,
Vas   : 200L+

For the Mykey plan mentioned, with 190mm depth chamber, below Older drivers (in order of preference), "should", be very good. There maybe newer drivers, with similar T/S.

PD1850 MK1/2 (Don't know about the /2 series)
Void V18-1000
B&C 18TBX100
PD1852
PD186 MK1      (NOT /2 series)
FANE 18XB 800W

Many 18sounds drivers may not fit, due to depth of Scoop.

Compare T/S of above, to identify similarities.

With exception of PD1852, these are older drivers, Newer drivers may prefer larger chamber different throat.



Edited by levyte357- - 31 July 2020 at 5:26pm
"Gentlemen, you can't fight in here, this is the war room!!".
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nejten Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 5:29pm
Thank you! I understand that I will not be designing scoops in the near future, but now I have an idea of what goes into making one. Too bad a lot of 18 sound drivers wont fit scoops since ive seen some pretty impressive specifications on them!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote levyte357- Quote  Post ReplyReply Direct Link To This Post Posted: 31 July 2020 at 5:33pm
Originally posted by nejten nejten wrote:

Thank you! I understand that I will not be designing scoops in the near future, but now I have an idea of what goes into making one. Too bad a lot of 18 sound drivers wont fit scoops since ive seen some pretty impressive specifications on them!


Check it for your self, the Neos may not fit.

Look at driver mounting measurements, and estimate if it will fit, think the mykey plan has 1x chamber deeper  than the other.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2020 at 7:59am
https://www.google.com/url?sa=t&source=web&rct=j&url=http://audioheritage.net/files/Loudspeaker%2520Design%2520Cookbook%2520by%2520Vance%2520Dickason.pdf&ved=2ahUKEwjYwZbg7PfqAhXPsKQKHS8lCAAQFjACegQIARAB&usg=AOvVaw2A1ilhS2Laaoagsk79y8-i
Classic . Does not cover horns , just closed and ported boxes, but detailed explanation of speakers mechanical and electrical behaviour with lots of comparative measured graphs.

Other good introductory readings, not so much about designing speakers, but about how sound and sound systems work... can't design a part if you don't know a bit about the whole thing right?

Jbl sound system design guide

Mc Carthy's "Sound System design and optimization" is a very good read!

Reading the first parts of these texts you should get acquainted with the basic laws involved, wavelenghts and space realationship etc.

In hornresp you can play with speaker parameters in the loudspeakers wizard to get a feeling of the impact they have.
Learn to look at impedance, displacement and the whole graphs of hornresp, not just frequency response.





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Post Options Post Options   Thanks (0) Thanks(0)   Quote nejten Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2020 at 9:41am
exactly the stuff i was looking for, awesome!
From small acorns oak trees grow.
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