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Custom Reflex for P.D.18" |
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RkH 
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Joined: 06 September 2016 Status: Offline Points: 21 |
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 Topic: Custom Reflex for P.D.18"Posted: 02 December 2019 at 3:01pm |
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I asked them and they're using 18 for the cone wood and 15 for the rest of th box. I was going to use all 18mm entirely, but the price they offer the product seems good.
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DMorison
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Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649 |
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Posted: 27 November 2019 at 4:51pm |
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I don't, no sorry. You might contact Blue Aran about either buying the rights to the design off them for a small fee, or getting them to do a run of cabinets for you in your preferred wood if its much of an issue for you.
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RkH
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Posted: 26 November 2019 at 8:28pm |
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Hi thanks. The design looks good but the wood looks to be lower quality that i currently use. The pictures are not in very good quality (the ones i use do have 13 layers phenolic birch), so i think im gonna pass, but i the design is good. Maybe i can replicate it. Do you have the design? |
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DMorison
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Posted: 26 October 2019 at 10:25am |
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By the way, if you're still not confident about the design process and want a simpler option, the JAM S118 kit sold by Blue Aran appears to be just about perfect for this driver: http://www.bluearan.co.uk/index.php?id=JMSKIT118&browsemode=category
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DMorison
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Posted: 24 October 2019 at 2:55pm |
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Right, so now change the display to Cone Excursion and the input section to Signal and increase the Driver input voltage till you get the excursion up to Xmax.
Then change the display to Rear port Air Velocity and the input section to Vents and start adjusting the vent dimensions to match what you plan to build. For example, if you want a cab that's 550mm wide externally, built with 18mm timber, with a shelf port having brace down the centre you would model 2 ports each 24.8cm wide by however tall it takes to get the airspeed reasonably low. Once you have that done, open the spreadsheet, input the vent width, vent height, number of vents, Vb and Fb in the appropriate column and it'll calculate the new vent length for you. Cheers, David
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RkH
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Posted: 24 October 2019 at 1:10am |
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https://i.imgur.com/PH2oTsg.png
Here is the result after adding the information about the loudspeaker and tuning freq/box liters. I think im blank. How should I procedure now? |
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RkH
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Posted: 09 October 2019 at 8:27am |
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Not yet, I will do soon. I will keep you updated. Thank you |
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DMorison
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Posted: 04 October 2019 at 1:15pm |
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That's what the spreadsheet is for ;) If you have any problems with it after trying things out, post back what you're struggling with and I'll see if I can help.
IMO, no, that's too high - you'll get an ugly sounding peak around 70-80Hz, possibly compromise the time response (ie how "fast" it sounds) and loose a lot of low end, so you'll be disappointed when you use it on it's own before getting the scoop sorted.
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JonB67
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Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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Posted: 03 October 2019 at 11:19pm |
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Have you simmed it in winisd?
You're at the point where you're going to start answering your own questions when you see the graphs.
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RkH
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Posted: 03 October 2019 at 9:40pm |
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Thank you for these clarifications.
How much shorter should it be? How can I know it? Would it viable to tune it to 60hz? I don't matter to port it to lower frequencies because I will add a Scoop later for that band. |
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DMorison
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Posted: 03 October 2019 at 12:59pm |
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Yes, that is correct. When the vent is built in a corner or along the bottom of the cabinet like you want, you can make it shorter than predicted by WinISD and still get the correct tuning frequency.
I think for that use you will be OK with the smallest and highest tuned of the options I suggested, 150litres tuned to 40Hz. You can always use an analyser like in Audacity to check your music to be sure. Good luck, David.
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RkH
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Posted: 02 October 2019 at 6:44pm |
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Thank you for the extensive message, i'm not so lost as i was thinking, but i have to read again the 'port' explanations you give. We are suppossing that WinISD calculates the port lenght centered on the box. Something like this
https://www.supravox.fr/wp-content/uploads/2018/02/Supravox-produit-1050x1400-KIT-135LB-01-1.jpg But i want that the cab looks like this: http://www.lean-business.co.uk/SPEAKER_PLANS/CIARE%2015.00%20SW%20BASS%20REFLEX.gif When converting it, is it supposed that the vent changes its dimensions when changing the position on the box? Talking about other think, I said a freq. like 20hz, but no for port tunning, just that is going to play 20 to 150 at the beggining. Later i will add a scoop bin so I can separate for lower-end frequencies without distortion. That's why i think i don't whant to tune it so low, because in the future is gonna run higher frequecies like 90 to 250 or something like that. Music is gonna be black music from 60s to 90s. There are a lot of songs with upper bass and also lot of them have subharmonics on the bassline, above all in 80s and 90s songs. So I suppose that my project needs a smaller box, but the prototype its true, it has to be usable for smaller and mid rooms like restaurants and cafes. |
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RkH wrote: