I want to make BassReflex floorstander with 6" Seas Prestige. My first priority is extended bass response, no matter what size box will be. I'm in mix between Seas CA18RLY and CA18RNX.
Using Hoge's formula I got:
CA18RLY - f3 = 31Hz, Vb = 55L
CA18RNX - f3 = 47Hz, Vb = 17L
Obviously CA18RLY seems like better choice, but Troels Gravensen mention several times that RNX is better for bass, and now i'm confused 🙂
"The CA18RNX is a long-throw, large voice coil variant of the Prestige paper cone drivers handling bass better than the CA18RLY, which holds the classic 1" voice coil."
what do you guys think?
Using Hoge's formula I got:
CA18RLY - f3 = 31Hz, Vb = 55L
CA18RNX - f3 = 47Hz, Vb = 17L
Obviously CA18RLY seems like better choice, but Troels Gravensen mention several times that RNX is better for bass, and now i'm confused 🙂
"The CA18RNX is a long-throw, large voice coil variant of the Prestige paper cone drivers handling bass better than the CA18RLY, which holds the classic 1" voice coil."
what do you guys think?
Use a bigger box & tune lower with the CA18RNX... (~25L, 37Hz, or go crazy & use 2, 60L @ 33Hz...???) CA18RLY gives a very natural sounding bass, but doesn't stay clean when you wind it up.
re:"no matter what size box will be" - if this is true, use a bigger driver
re:"no matter what size box will be" - if this is true, use a bigger driver
I second the call for using either a bigger driver or of course additional drivers.
EDIT: A MLTL may give you more extension as well.
EDIT: A MLTL may give you more extension as well.
Thanks for replies. I forgot to tell that that I don't have need for a much SPL, and on simulation ca18rly gives flatter bass response. Troels also said that RLY haves flatter midrange. So I'm leaning more toward ca18rly at this point. Is there something else I should be aware of with ca18rly, despite lower max SPL? Am I missing something?
Here are simulations for ca18rly at 54L box, and ca18rly at 30L.
Here are simulations for ca18rly at 54L box, and ca18rly at 30L.
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Gorantzhe,
This is what I would do if in your shoes. I'd go with RNX. Greater Xmax
of +/- 6 mm, 39 mm voice coil which gives a bigger surface for heat
dissipation, Qts of 0,31 which will probably be a bit higher if measured
and that is exactly what one wants for a good BR box integration. Worth
the extra cost over RLY.
This is what I would do if in your shoes. I'd go with RNX. Greater Xmax
of +/- 6 mm, 39 mm voice coil which gives a bigger surface for heat
dissipation, Qts of 0,31 which will probably be a bit higher if measured
and that is exactly what one wants for a good BR box integration. Worth
the extra cost over RLY.
I've used both in a TMM floorstander design and above 100hz, they're virtually identical IMO. Simply put, the RLY works very well sealed but needs a huge box ported and in such a box becomes SPL limited. The RNX would be the better choice for a ported floorstander IMO.
With this in mind, a 36 Hz MLTL with the driver location ~optimized for a ~ 8 ft ceiling height, so the HF would be either above or below it depending on desired seated ear height:
L = 56.68”
WxD = 53.951”^2 [recommend 5.774” x 9.343” or other acoustic ratio]
Zdriver = 19.78”
Zport = 45.34”
Dport = 3”
Lport = 3.5”
All dims i.d. and approximate. Sim based on posted specs, 19 mm thick material with additional 19 mm thick base and minimal internal damping.
With a net Vb > [published] Vas, it has plenty of vent, damping tuning flexibility if Qts is higher or could be turned into a TL or ~IB or add ballast to reduce net Vb to get a higher Qtc if desired.
GM
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Just built new 47L cabs for my CA18RLYs for my new listening space, 3 way with Vifa TG9 & SEAS 22TFF, add some South Aus Shiraz, I don't need to die, I'm already in audio heaven... these are a classic, (now need to moan that there are no SEAS distributors in this part of the world anymore....)
Sounds great, but isn't 47L rather large for this size of driver, whereas one could have used an 8", no?
PeterMcK, can you share details of your build when you get a chance, please? I have the drivers minus the Vifa already.
bad pic attached, the Mid & Tweeter are in their own 2 L cab; crossover: They're well behaved drivers so a simple crossover suffices; 1.5mH in series with the woofer; 47uF & 0.2mH in series with the mid; 2.7 ohms & 3.8uF in series with the tweeter, & 0.42 mH across the tweeter, tweeter reverse phase, assumimg I'm reading my dodgy notes correctly. Port for the woofer is 68mm dia., 105mm long
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I think it is very hard to make a floorstander bass reflex. Because of the necessary cabinet ratios it becomes a form of ML-TL. A BR mode will not suffice to determine the expected bass response.
dave
I should mention that the width of the mid-tweeter enclosure is 140mm, which gives a Baffle step freq. of 820 Hz, the lower crossover point. Tweeter is crossed over at 3 KHz.
Re: Dave's point, dimensions of the woofer box are 23 W x 36.5 D x56 H (Cm, internal), so deeper rather than MTML shape. I also glued together a couple of offcuts at right angles, as a brace for the sides. Drilled large holes in it and tied a large wadge of poly damping material at the apex. Works very well, the sides are 12mm ply, but very well damped
Re: Dave's point, dimensions of the woofer box are 23 W x 36.5 D x56 H (Cm, internal), so deeper rather than MTML shape. I also glued together a couple of offcuts at right angles, as a brace for the sides. Drilled large holes in it and tied a large wadge of poly damping material at the apex. Works very well, the sides are 12mm ply, but very well damped
How is it a tower if it is only 59 cm tall? Usually you ar looking at closer to a fll metre.
dave
dave
Hi Pete,
good to see you still doing new speaker projects
I also love EBS design, ie extra large volume, reasonably high Q driver (>.3) & nice low box tuning.
I've just finished some massive 100L three ways using Peerless 850146, Vifa M18 & SS HDS tweeter.
Cabinet is tuned to 25hz - lovely effortless extended low bass
Cheers Clay
good to see you still doing new speaker projects
I also love EBS design, ie extra large volume, reasonably high Q driver (>.3) & nice low box tuning.
I've just finished some massive 100L three ways using Peerless 850146, Vifa M18 & SS HDS tweeter.
Cabinet is tuned to 25hz - lovely effortless extended low bass
Cheers Clay