[AudioSoul]

I have the Audio Nirvana Super 8 cast frame drivers in a cabinet I built out of birch ply. It has a 4" port. I am very impressed with the sound of these speakers. However, they do have the shortcomings of a single driver design. Ie, lacking in the top and bottom ends. I am thinking of adding a super tweet for the top end. I have been thinking about the bass end. I cannot add a subwoffer (no room) has anyone ever done a passive radiator in the same cab as the single driver? I am thinking maybe a combo vented/passive radiator. I know a single driver cannot handle a sealed cabinet. Thoughts please.......

[Russell Dawkins]

Beware!! This way, madness lies 

Seriously, you could probably add a tweeter of some kind fairly easily, since you can let the AN run full range upwards, I guess, but I wouldn't mess with any scheme to try to get more bass/extension out of the bottom.
If you like the bass end but it's just too light, leave it and use a supplemental sub in a separate box, I'd say. Can't you fit one under or behind some furniture? Let the 8 incher do what it does best - wide range mids.
Easier on your head, ears and patience.

[JCS]

I have doubts about an improvement by designing a cabinet with a passive radiator vs. a port. They do very similar things.  Now you could work on a different cabinet design that achieves a lower F3.  I don't know anything about the AN drivers (I've stuck w/ Fostex.)  You might look around at places like http://www.planet10-hifi.com/ for designs.  If you are looking for software to help w/ design, I can recommend Martin King's MathCAD worksheets--well worth the $25 cost. (If interested, check them out at www.quarter-wave.com )

Cheers,  Jim

[chrisby]

I have the Audio Nirvana Super 8 cast frame drivers in a cabinet I built out of birch ply. It has a 4" port. I am very impressed with the sound of these speakers. However, they do have the shortcomings of a single driver design. Ie, lacking in the top and bottom ends. I am thinking of adding a super tweet for the top end. I have been thinking about the bass end. I cannot add a subwoffer (no room) has anyone ever done a passive radiator in the same cab as the single driver? I am thinking maybe a combo vented/passive radiator. I know a single driver cannot handle a sealed cabinet. Thoughts please.......

A lot of generalizations in the above,  but probably most problematic is I know a single driver cannot "handle"  a sealed cabinet.    What exactly do you mean by "handle", and how did you arrive at that conclusion?

For example, and by no means intending to compare qualities between 2 drivers of which I've not heard both, the little Mark Audio CHR70 driver comports itself quite nicely in a variety of enclosures, including a 5 liter sealed box.  Is it limited in terms of ultimate SPL and extension to lowest octave and half or so?  Well, yes - most certainly when compared to an 8" driver of perhaps 8-10dB more sensitivity in a floorstanding height MLTL or  BR, etc - but in the right application, it's a very delightful and silly affordable option. 


Remember it's the art of the matching driver & enclosure design for any particular application that will yield the "right" balance. 

remember too, that there is no single "right", but probably even more ways to be "not right at all" 


Regarding specific enclosure design using a single FR driver and passive radiator(s), take a look at


http://www.decware.com/newsite/HDT.htm






Steve has some interesting ideas

[AudioSoul]

   I guess what I meant by my drivers couldn't handle a sealed inclosure is that they have limited excursion (cloth surrounds)
  Maybe it was a bad idea.....

[planet10]

Based on this drivers specification, you will need a largish horn enclosure to get any bass, or an EQ filter that knoks the efficiency back dramatically.

dave

[mightym]

Have you tried adding a little series resistance?  or   using a single run of Cat 5, or magnet wire to do the same thing?

What kind of amp? SS, or glass?

Chrisby beat me to the Decware thing above...

John

[AudioSoul]

I am using all tubes. A Anthem L-1 line preamp, a Jolida JD-9 phono preamp and a AES Super amp running in triode mode in pure class A 15 watts, with no negative feedback.......

[TerryO]

I have the Audio Nirvana Super 8 cast frame drivers in a cabinet I built out of birch ply. It has a 4" port. I am very impressed with the sound of these speakers. However, they do have the shortcomings of a single driver design. Ie, lacking in the top and bottom ends. I am thinking of adding a super tweet for the top end. I have been thinking about the bass end. I cannot add a subwoffer (no room) has anyone ever done a passive radiator in the same cab as the single driver? I am thinking maybe a combo vented/passive radiator. I know a single driver cannot handle a sealed cabinet. Thoughts please.......

Just a note: You can't really use a port and passive radiator combination that will work. One or the other, but not both as they will be mutually exclusive.

Best Regards,
terryO

[AudioSoul]

  Hi Terry, I know I cant have both a vent and a passive radiator. The Passive would replace the vent. Do you think this is a
  doable situation? I know it's a crazy idea, I am just not that experience with these things. I dont want to ruin the cabinet
   either. Thanks, David......

[TerryO]

  Hi Terry, I know I cant have both a vent and a passive radiator. The Passive would replace the vent. Do you think this is a
  doable situation? I know it's a crazy idea, I am just not that experience with these things. I dont want to ruin the cabinet
   either. Thanks, David......

I haven't been around much lately so I missed this one...sorry.

The answer is yes, you certainly can use a passive radiator with a single driver. A general rule of thumb is to select a passive radiator with 1.5 to 2 times the area of your driver. Remember that you will probably have to add mass to the PR to attain the correct tuning. There are several advantages to using a PR over a port, but the PR is also more expensive. With a nice driver like the AN Super 8, I'd probably go with a PR.

Best Regards,
TerryO

[planet10]

There are several advantages to using a PR over a port

And a number of disadvantages.

1/ a zero in the response caused by the finite compliance of the diaphragm (a perfect PR would have infinite compliance)
2/ additional distortion from the nonlinear suspension of the PR
3/ moderate ripples in the response above and below the F3 point.

dave

[pjanda1]

FWIW, the main advantage of a PR is that it makes some cabinet tunings possible that would be otherwise very difficult to achieve.  If you are trying to tune a very small sub cabinet very low, like a low compliance, low Qts driver in an EBS alignment (a vented box with a TC Sounds or AE woofer), the port can get ridiculous.  I used a PR for  a BR box with the MCM 55-2421 to a create a sub with serious extension in a 1 cu ft box.  A port would have needed to be feet long to achieve that.  Generally, port size is never a problem with fullrange driver tunings, so all you get are disadvantages.

Paul