Discussion split from pictures

[Cloth Ears]

Guess I'm thinking of home set-ups...

 

[v-bro]

I love these:

 

[v-bro]

And this one:

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[navin]

I like this one:

An externally hosted image should be here but it was not working when we last tested it.

....

how big is the woofer?

In fact given that OB speakers need big woofers it would be nice to know what the size of the woofer/ baffle is for all the speakers shown just to have some reference.

 

[Ray Collins]

felix,
Will you be able to provide a picture of the back of your OB?

Ray

 

[v-bro]

It's a Visaton BGS40 18" woofer....
Design is Visaton 'Nobox'

The other one is a DIY design from a dutch audio forum, it's more or less a Jamo clone using very cheap drivers.....(also >40cm/18")

 

[lazenna]

V-bro I think we have the same tastes I love the look of all the speakers you posted.I'm thinking of something along the lines of the Jamo but using a 15" or 12" dual concentric for midrange and tweet duties.What woofers for 2x15" bass do you guys recommend.Prefer cast baskets.I am thinking about the Dayton rs15".
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=295-468

 

[v-bro]

Hi Lazenna, I think a great choice!

Don't let anybody tell you they aren't!😀

 

[v-bro]

It's a Visaton BGS40 18" woofer....
Design is Visaton 'Nobox'

The other one is a DIY design from a dutch audio forum, it's more or less a Jamo clone using very cheap drivers.....(also >40cm/18")

Uhm correction, I think 40cm is in fact 15"....
🙄

 

[Cal Weldon]

15" = 38 cm
18" = 46 cm

 

[navin]

What woofers for 2x15" bass do you guys recommend.

Prefer cast baskets.I am thinking about the Dayton rs15".
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=295-468

Hi Lazenna, I think a great choice!
Don't let anybody tell you they aren't!😀

1. what makes a woofer a good choice for dipole? I mean what do we look for? Qms? Qts? Fs? Any guidelines?
2. That Dayton woofer looks well made but how ouwld it compare to old favs like the NHT1259, Bhrama, Shiva, Tumult or any of the drivers from Eminence (Kappa 15), Selenium (SLF 15), or even pro drivers like the JBL 2235 or Peavey low rider/pro rider subs.

 

[v-bro]

I think if there's enough surface you don't need optimal Q. As long as you have suffiecient hub and surface anything will work, I think preferrably high Qms and Qes.

Allthoug my 'pro' seventies JBL 2220A have very low Qts and work quite nicely in a medium sized room and pretty large baffle (with sides) and the baffle placed in contact with the floor.

 

[ashok]

Can a maths expert tell us what happens to Qts and spl figures if we change a cone with another one with knowm mass , surface area and (expected ) resonance frequency ?

If you ask why , it's to guess what will happen if we graft a bigger cone on to a smaller frame. Say an 18 inch cone on to a 12 inch frame with various mods to the frame.
Qts should go up and Fs should fall , possibly Qms should go down. Sensitivity would suffer most I think.

Outlandish ... yes ! The web is full of far more outlandish things !
😀

 

[lazenna]

Trying to narrow down my search for bass drivers going by experience or specs which would seem to be better? Ficar audio SSD18


DUAL 1 | DUAL 2

Fs: 24.7 Hz | 24.3 Hz
Re: 0.75 Ohms/coil | 1.5 Ohms/coil
Qms: 4.88 | 4.96
Qes: .75 | .69
Qts: .65 | .61
Mms: 296g | 308g
Cms: 0.14mm/N | 0.14mm/N
Sd: 1210cm^2 | 1210cm^2
Vas: 285 l | 285 l
Spl: 89.4dB 1W/1m | 89.6dB 1W/1m
Bl: 9.3 N/A | 14.1 N/A
Xmax: 21mm
Rms: 800W
Sealed box: N/A cuft
Ported box: 6-10 cuft @ 33Hz
Sub OD: 18.500”
Cut ID: 16.750”
Mounting depth: 9.500”
Displacement: 0.22cuft


Product code: 01918


Price: $ 239.00
*shipping is included




Power Handling: 800 watts RMS

Sensitivity: 89db (2.83 volts)

Impedance: 4 Ohm Nominal (SVC)

Dimensions

Outside Diameter: 46.2cm (18 3/16")

Mounting Diameter: 42.4cm (16 11/16")

Depth: 24.8cm (9 3/4")

Recommended Box Sizes

Sealed: 130 litres (4.6 cu. ft.)

Ported: 200 litres (7 cu. ft.) 19Hz tuning

EBS: 350 litres (12.4 cu. ft.) 15Hz tuning



Mach5 audio IXL-18.4
T/S Parameters

Fs = 17.7 Hz

Re = 3.4 Ohms

Qes = 0.39

Qms = 5.59

Qts = 0.37

Mms = 434.3 grams

Rms = 8.69 kg/s

Cms = 0.184 mm/N

VAS = 274.1 litres

Sd = 1029.2 cm2

Xmax = 22 mm

Cone Diameter = 36.2 cm

$210.00

 

[v-bro]

They all seem not to excel much in sensitivity which I think gives you less margin to play with correction. On the other hand they all have very high powerhandling, which means you can regain the margin by using a larger amplifier.

The DUAL 1 seems like the best choice...

 

[lazenna]

What about these Ciare 18" model 18.00NdW1 price** $210.00
weight 6.3 Kg vc size 100mm
size 18" Fs 29hz
power handling 500W (AES) Bl (Wb/m) 24.85
Vas (M3) 0.29643 Sd(M2) .115209
SPL 1w1m 100.5dB Qms 12.36
Xmax 7mm* Qes 0.32
Frequency 30hz-1khz Qts 0.31
magnetic induction (T) 1.2

 

[v-bro]

The 18.00ndw1 has a pretty nasty peak between 1 and 2 Khz. This is not a very big problem, but you can't get away with a simple 6db/oct filter....to say the least....

Furthermore they traded excursion for sensitivity, which is not a bad thing given the fact the woofer is BIG. The low resonance frequency comes in very nice.

Conclusion: It can work, but it needs a bit more effort....

 

[v-bro]

Ciare 18.75 NdW seems more suitable....

 

[peterbrorsson]

Here is an extreme dipole. I've no experience with ob but will have in the future. Like the bass from ob!

http://www.rauna.com/slides/speakerwalljpg.html

 

[v-bro]

It looks like the designer frequently kills mosquitos with a bazooka 😀 sure it will rock the planet, but I could think of a few possible or theoretical flaws there...

By the way with the way they're place they're hardly OB, they rather use the corners of the room as enclosure...