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Post by keith1962 on Mar 22, 2016 22:51:51 GMT
So the plan is 3 way OB with Najda DSP crossover and room correction below 300Hz. and I have a few questions?  . i have Beyma tpl150H and intend to get a pair of Beyma 12p80 nd bass mid drivers to play beneath them. Both will be played dipole and below them will be a 15" or 18" in a U frame. At present I am favouring the Fane colossus 18XB mainly because I heard it in a U frame at Scalford and it worked extremely well even though the Qts figures would suggest that it shouldn't. Does a low Qts in open baffle just mean that the response might not go as low as you would expect? i need an amp for the 18" and have an option on a Sony ta f670 Es which is 100W and 100 damping factor. The power is not necessary as the 18" is 98% or more but control is important. Would a pro chip amp such as Inuke or one of the cheaper Crown amps be better or would that not be too good up to 300 to 400 Hz which is where I propose to cross to the 12"? What is the best material for the baffles, 18mm birch ply or mdf? The pro scene use ply as it is so much more robust but does it also sound better? Apologies for all the questions in a first post Keith. |
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Post by John on Mar 23, 2016 5:25:29 GMT
I like your thought process around this open baffle
The fane I heard a few times and works well and like what the Beyma tpi150h does. I do not know the other Beyma driver but should work well
If using the fane around 300 to 400 I stay from the Inuke needs to be a bit lower to get the best from it But the Crown will work well and that would be my preferred amp for this
I am looking forward to reading your journey
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Post by keith1962 on Mar 23, 2016 9:30:51 GMT
I like your thought process around this open baffle The fane I heard a few times and works well and like what the Beyma tpi150h does. I do not know the other Beyma driver but should work well If using the fane around 300 to 400 I stay from the Inuke needs to be a bit lower to get the best from it But the Crown will work well and that would be my preferred amp for this I am looking forward to reading your journey Thanks for the response John. Good to hear you think the Fane 18" works well. The 12" from Beyma gets very good reports on diyaudio especially crossing to the tpl150 which beyma seem to have had in mind when designing it. Which Crown amp (or any other brand?) would suit? Not too bothered about power as I said earlier due to the efficiency of the Fane but would like good sq up to 300 to 400 Hz at the best price so no bells and whistles required. Is there a difference in the sound between Baltic birch ply and mdf and in what way? I will try to get pictures and post them as I go but they will only be phone pics. I will be using a Leben CS300SX on the tpl150 and an Hiraga Le Monstre on the 12". Keith. |
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Post by John on Mar 23, 2016 15:49:28 GMT
With regards ro baffle I would say good isolation is very important in getting the right sound. I have used 3/4 birch ply and 40mm MDF I preferred the 40mm MDF but I also paid more attention to isolating the driver from the baffle by using a 10mm mounting plate
The Crown XLi 1500 might be a great match
Once you get that crossover dialed in you going to have a pretty special system Keith
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Post by keith1962 on Mar 23, 2016 17:53:58 GMT
Thanks John,
Will have to see what materials I can get locally and go from there. What material did you use to make the isolating gasket?
Keith.
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Post by Greg on Mar 23, 2016 20:04:17 GMT
I have used 3/4 birch ply and 40mm MDF I preferred the 40mm MDF but I also paid more attention to isolating the driver from the baffle by using a 10mm mounting plate Keith I know a couple of people who have had remarkably good results using thick Perspex. I can't remember the actual thickness but probably between 10 and 20mm. One build was known as 'Quasars' designed and built by James Doddington. I might have a picture hidden away so I'll have a search and publish if I can find one. pre65 might be able to add more detail on these. The other is Mark Jeffs also known elsewhere as Island Pink. Perspex is well worth considering albeit more expensive. |
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Post by John on Mar 23, 2016 20:26:30 GMT
I remember Ali mentioning that too I not heard this for myself yet
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Post by Greg on Mar 23, 2016 21:28:39 GMT
Here you go. This was from Eggfest 4, 2009. Eggfest was the preceding DIY events to the now more commonly known Owston. Sorry about the poor picture quality.  By the way, the next Owston is 18/19th June if anyone is interested. |
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Post by pre65 on Mar 23, 2016 22:06:19 GMT
The inner pair in that picture are Nick Gorham's, and were the inspiration for my OB speakers.
I remember that day at Eggborough. 
*
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Post by Greg on Mar 23, 2016 22:06:39 GMT
Here is IslandPink's effort under construction. To keep the price down, he just used the Perspex for the baffle, using other materials for the rest of the construction.  |
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Post by Greg on Mar 23, 2016 22:15:34 GMT
The inner pair in that picture are Nick Gorham's, and were the inspiration for my OB speakers.
I remember that day at Eggborough.
Yes, and the outer pair are Paul's lash up and to be sure they were a lash up, but he was just experimenting to see if they would work for him. Considering the standard of construction, they sounded surprisingly good.  |
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Post by pre65 on Mar 23, 2016 22:24:42 GMT
Having heard many and various OB speakers it seems difficult to make a pair sound bad. 
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Post by keith1962 on Mar 23, 2016 22:55:51 GMT
Having heard many and various OB speakers it seems difficult to make a pair sound bad. This is really good to hear, although rest assured I will be giving it my best shot |
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Post by keith1962 on Mar 23, 2016 22:57:04 GMT
Thanks to everyone for all of the valuable info. Keep it coming.
Keith.
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Post by Greg on Mar 24, 2016 0:02:58 GMT
Here's another pic of Island Pink's baffles under development. I have checked and can confirm he used 20mm thick Perspex although I think James' Quasars were made with something thinner. You're probably in the realm of £250 for 20mm Perspex but I think it's worth it.  |
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Post by John on Mar 24, 2016 5:19:45 GMT
What does it do to the sound Greg
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Post by keith1962 on Mar 24, 2016 17:35:04 GMT
Those Perspex ones do look very nice! High WAF imho. Is there any benefit to be had sound wise from front mounting the drivers, front mounting with the driver in a rebate or rear mounting?
Keith.
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Post by Sovereign on Mar 24, 2016 17:42:09 GMT
Great thread Keith, I've had OBs for years now. And I plan to go active very soon, all the best with your build..
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Post by John on Mar 24, 2016 18:30:10 GMT
Having heard many and various OB speakers it seems difficult to make a pair sound bad. This is really good to hear, although rest assured I will be giving it my best shot Unfortunately I heard a few in the past |
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Post by keith1962 on Mar 24, 2016 20:22:41 GMT
Yes, well, I think I have the ingredients correct now, it's a case of not under-cooking or, alternatively, burning the bu--er now!!!
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