W3-871s over bright.

[sreten]

Hi,

Falcon Acoustics wind whatever value you want, but 6.8mH will be fine.

/sreten.

 

[Puggie]

Maplin do a 150Hz low pass crossover module, can't remember the price but its not a lot, from memory that has a 6.4mH inductor in it, chunky wire and a laminated iron core, not the last word in HiFi maybe but its an option, I think you get a cheapy 168uF electolytic cap too

I have some 6.4mH and 8mH air core inductors, they are damn big (about 4.8kg each)

 

[sreten]

Hi,

the maplin c/o is £4.99 and advertised as a low pass 100w 150Hz 4 ohm subwoofer c/o.

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

http://www.maplin.co.uk/Module.aspx?ModuleNo=29611&criteria=crossover&doy=28m2

/sreten.

 

[sreten]

Hi,

Falcon Acoustics wind whatever value you want, but 6.8mH will be fine.

/sreten.

Maplin do a 150Hz low pass crossover module, can't remember the price but its not a lot, from memory that has a 6.4mH inductor in it, chunky wire and a laminated iron core, not the last word in HiFi maybe but its an option, I think you get a cheapy 168uF electolytic cap too

I have some 6.4mH and 8mH air core inductors, they are damn big (about 4.8kg each)

Hi,

the maplin c/o is £4.99 and advertised as a low pass 100w 150Hz 4 ohm subwoofer c/o.

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

http://www.maplin.co.uk/Module.aspx?ModuleNo=29611&criteria=crossover&doy=28m2

/sreten.

Hmm....

all the fault of a typo in my post, we are actually talking about 0.68mH.

/sreten.

 

[toseland]

Sreten,

I now have components from Madisound. Went for a Solen 100uf.
I still think they a bright with 5.6 Ohms so I will play around with the resistance. Much better than before.

I cannot see where the 15 Ohm resistor is mentioned.
Does it make a difference where the components go, series capacitor
15ohm to ground then series notch or some other way?

Regards BT.

 

[Tenson]

Hi,

Just a quick question about baffle step - Why are the calculations always based on the width of the baffle and not the width AND height? Surely sound doesn't care which is which and both will has as much effect? Do they presume a square baffle or something?

Can you give me a clue as to what I can expect if I put a W3-871 in a baffle 27cm wide and 45cm high with the 871 near the top and a woofer below? The baffle has rounded edges.

thanks

 

[Vikash]

Because the width is generally always the smaller and dictates the starting point of it.

You'll need to measure to optimise for your design.

 

[Tenson]

Thanks, I will probably buy a pair from your site! By the way who is that in your avatar? Been wondering for a while

 

[lovechild]

There's an article on True Audio by John L. Murphy, he developed a rule of thumb for BSC click! serves as a good starting point - but as Vikash say, it's always better to messure!

best, LC

 

[Tenson]

Hmm if a tube with the diver in the center is bad (i.e. a round baffle) how does this behave if the driver is the exact size of the end of the tube? The same as having no baffle?

 

[mrlots2do]

By the way who is that in your avatar?

He be 'Kramer' a comic character from 'The Steinfeld Show'. This US primetime show ended last year or year before, now showing as reruns on many channels is US.

 

[Vikash]

The avatar is Kosmo Kramer from Seinfeld. Hilarious character.

Having the driver the same size as the tube is the same as having the driver fixed to a round baffle. The driver edge just becomes the baffle edge for all intents and purposes. The same issue of all edges being the same distance from the driver edge is still the problem.

 

[Vikash]

I didn't make the spheres I bought them in a department store in the UK.

Where, what material are they made from and how much?

 

[sreten]

Hmm if a tube with the diver in the center is bad (i.e. a round baffle)
how does this behave if the driver is the exact size of the end of the tube?
The same as having no baffle?

Baffle size and driver size become the same.

The smaller the driver size compared to the baffle the more
distinct the diffraction ripples become, as there is less path
difference for the various parts of the moving cone surface.

/sreten.

 

[sreten]

Sreten,

I now have components from Madisound. Went for a Solen 100uf.
I still think they a bright with 5.6 Ohms so I will play around with
the resistance. Much better than before.

I cannot see where the 15 Ohm resistor is mentioned.
Does it make a difference where the components go, series
capacitor 15ohm to ground then series notch or some other way?

Regards BT.

Hi,

As I mentioned earlier Zaph's filter is designed to be listened to off
axis, on axis it will be bright. Point them straight ahead not toed in.
This method improves the overall room power response in the treble.

Good that they are much better than before.

The 15 ohm resistor is not mentioned because its my addition.

Where the components go does matter if its wrong,
the way you say above is fine.

/sreten.

 

[Svein_B]

I have used the following Notch filter with good results both in the Cyburgs Needle and a small 1.5L BR.

L: 0.56 mH. Air core coil, 0.8mm.
C: 6.8 uF. polyester film (Bennic MT)
R: 6,8 ohm wirewound 5W
(all components are connected in parallel, and inserted into the speaker wire)

This is the filte specified in the published designs for both the Cyburgs Needle and the Lancetta.

I once tried to "upgrade" the cap to a Solen MKP . This made the sound very sharp, and I was happy to put the cheaper polyester cap back in.

A better coil (1.2 mmm wire or copper foil) might be even better, but I have not tried since I deliberately aim for low-budget DIY solutions. Maybe that Solen might also be better in a different environment than mine?

I find the sound with this filter to be "polite", and maybe a litte small in dynamic scale. When watching TV i do however sometimes need to hit the mute button to be sure if ambient sounds are from the TV or my house so it must sound kind of natural

Svein.

 

[Tenson]

Hi sorry to hijack the thread but I just bought some 871S's from Vickash's site. I need some advice for an enclosure size for them.

I am going to use them with a woofer crossing over at 400-500Hz. I am doing this to (hopefully) get a good max SPL from them so they don't mind a bit of rock!

Anyway what would be an ideal size for a closed box? Scott suggested a small box would be good when I was looking at the JXR6 but I read somewhere on this forum that the 871S gets a 'honky' midrange in a small box.

I am going to make it with no parallel sides so I hope that would help. The smallest baffle size (when on top of the woofer cab) will be 27cm.

Thankyou

 

[Svein_B]

You must try this:

Tangband in a plastic bottle

Serious!
No parallel sides, small baffle, 1.5L BR, .....

 

[Tenson]

No parallel sides? Aren't they all parallel? Though if the end was closed and heavily stuffed it is basically a 'real' transmission line I guess.

Anyone tried the Tangband in a small horn? In my case I was thinking of a rectangular one the width of my baffle (27cm) and about 15cm or 20cm high simply from looking at what I have already.

 

[toseland]

I've been playing around. with the resistive element using 3x3W metal film using 2x18+27 in parallel close to 6.8 did seem a bit dull. Using 15+18+27 in parallel seems better. Just need to do more listening.


Regard BT.