box for 6.5" audio nirvana

[ranaya]

Hi –

I just got myself a pair of 6.5” standard Audio Nirvana FR drivers. Although I have little to no experience with speaker building, I do have above average woodworking and basic soldering skills. I plan to power them with a Super T-amp (~ 10 wpc).

From the little I have read about speaker design, the 6.5” AN drivers are best suited for a bass reflex type enclosure … or perhaps a transmission line? Although bass is good it will not be critical for the intended use. I plan to use the system to play my guitar with (> 70 Hz). You see, I have this cool digital guitar processor that I will be playing through (have already tried it through my current stereo system) and wish to have a portable stereo amp/speaker set up. I am not in a band and have no plans to perform live so this is basically for my personal enjoyment without extreme or super loud volumes.

I have seen the Fonken and I do like the style but would like an enclosure that has a tilted front baffle (~ 10 degrees from vertical) so that I can set the boxes on ground level and aim them up at me a bit. In addition, I would like the front baffle to have the largest dimensions of the box.

Are there plans for such an enclosure? How would I go about determining the interior volume and port dimensions?

Feel free to say this is a stupid idea too if you think this will be a waste of time, money, and effort … or even better, feel free to suggest other options.

 

[planet10]

I have seen the Fonken and I do like the style but would like an enclosure that has a tilted front baffle (~ 10 degrees from vertical) so that I can set the boxes on ground level and aim them up at me a bit. In addition, I would like the front baffle to have the largest dimensions of the box.

I don't get what you mean by the last sentence.

Are there plans for such an enclosure? How would I go about determining the interior volume and port dimensions?

I've done a 1st pass for the similar size Fostex, but haven't looked at the AN.

My technique for sesigning these is to model a BR that has a very specific roll-off shape and then i develop a longish port & then give it a very high aspect ratio, There are a number of ways to make the port fit into the box.

dave

 

[hm]

Hello,

for guitar try the BG20 Visaton in BR:

http://www.visaton.de/de/chassis_zubehoer/breitband/bg20_8.html

 

[Scottmoose]

The AN standard 6.5 is better than the Super for reflex / fonken loading. It won't really suit a TL though. You can do it, but there wouldn't be a great deal of point IMO.

I'd be inclined to build this, or something on these lines. Internal box dimesnions:

HxWxD 19in x 11in x 6.75in (latter at base, at top, 5.75in, which wll give you the backward angle you're after). Driver centre 6in down from the internal top. Port 2in diameter, 3in long, port centre 3in up from the internal bottom, front or rear (I'd suggest the front -I don't like rearward firing ports). Line the internal walls with carpet underlay or similar. Gives the attached response.

You should probably be able to calculate a Fonken from this too.

 

[ranaya]

I don't get what you mean by the last sentence.

What I meant was that I would like the depth of the box to be the smallest dimension.

I've done a 1st pass for the similar size Fostex, but haven't looked at the AN.

My technique for sesigning these is to model a BR that has a very specific roll-off shape and then i develop a longish port & then give it a very high aspect ratio, There are a number of ways to make the port fit into the box.

dave

Sorry, I am not up to speed on the technical terminology … so I don’t know what you mean by roll-off shape and high aspect ratio.

for guitar try the BG20 Visaton in BR:

http://www.visaton.de/de/chassis_zu...and/bg20_8.html

Thanks for the suggestion but I already have the 6.5” AN drivers and would like to make use of them … wish I had found this site before I bought them --- lots of great info even if it is a bit much to absorb.

The AN standard 6.5 is better than the Super for reflex / fonken loading. It won't really suit a TL though. You can do it, but there wouldn't be a great deal of point IMO.

I'd be inclined to build this, or something on these lines. Internal box dimesnions:

HxWxD 19in x 11in x 6.75in (latter at base, at top, 5.75in, which wll give you the backward angle you're after). Driver centre 6in down from the internal top. Port 2in diameter, 3in long, port centre 3in up from the internal bottom, front or rear (I'd suggest the front -I don't like rearward firing ports). Line the internal walls with carpet underlay or similar. Gives the attached response.

You should probably be able to calculate a Fonken from this too.

Thanks, the standard AN is the one that I have.

So you are suggesting a more simple bass reflex design than the Fonken? … with round/tube style port in front? I guess as a first build I should start out with a more simple design. I can try and redo the box Fonken style once I get up to speed on proper speaker design principles.

Your suggested dimensions are a good starting point, thanks. For the Fonken, would I just need to make sure the total volume for the square ports of the Fonken have the same total port volume as the 2in diameter x 3in long port you suggested above?

How do I read the response curves that you provided? I assume one curve is for the driver and the other is for the box? … or is one for the stand alone box and the other for the box with driver? … or something else?

 

[Scottmoose]

You could build this, or use this alignment as a starting point for a Fonken if you felt like it. High aspect ratio = tall but narrow vents with high resistance. Fonkens / Onkens, are sometimes close to aperiodic alignments because of this, although that varies somewhat depending on implementation & intentions. They're not really any harder to build than a regular reflex cabinet; you just need to cut a couple of extra panels, so don't let that put you off.

Re the BR plot above, the blue curve is the driver's infinite baffle response. The red curve is the system response of the driver and cabinet working together. When designing a reflex box, it's generally better to go for a response like this, smoothly rolling off below 100Hz as you're going to get a boost from room-gain. A max-flat QB3 / BB4 alignment will often sound bass-heavy in practice.

 

[whitelabrat]

Hi. I'm currently building Madisound's BK-16 flatpack for my ans6.5's. Sounds great. Probably could use a supertweeter. See my post in the Full Range forum.