In the thread where Scott posted a bunch of box designs there’s three sizes of Nostromo for the a11ms. I also see that each are designed for a different range of amplifier output impedance. My amp(s) are diy first watt clones, M2X, F6, F4, and Aleph J. Looking at the First Watt product page they all appear to have low output impedance of about 0.2 ohm or so. Does that mean the smallest one is best fit for my amps? I don’t understand that relationship. Can someone please help me understand? Thanks.
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Small or medium size. When in doubt, my advice is always to go one size up -you can always do something about that. If you start small, you're in the game of making a new pair of cabinets. 😉
Would the Sea Stacks be OK with these amps? I bought the pair of 11ms last year when they were on sale and I'm trying to decide on a box. They'll be supported by a sub so I'm not sure I even want a big box that goes as low as possible. Another project plan brewing is a 2-way monitor that will have a bass module added that crosses at 200Hz first order I think. Jeff Bagby designed one for the Continuum and Kairos kits at Meniscus and CSS has one as well. Could the 11ms nostromo go with something like that?
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We used SeaSTack with a variety of amps (SE, ACA, big mother AB, SIT-3, PP tubes). Remeber this is diy and any ML-TL can have added damping if the amplifier has such a high Rout that the bass becomes underdamped (boomy). The amp lacks damping which can be compensated for by increasing the loudspeaker acoustical damping.
Withe a reflex (nostromo) the damping has to remain kinda static, so we have to change the box volume. With an ML-TL we can change the damping.
The MAs are typically largely ambilivent to reasonable Rout amplifiers if in a properly selected diy box.
dave
Withe a reflex (nostromo) the damping has to remain kinda static, so we have to change the box volume. With an ML-TL we can change the damping.
The MAs are typically largely ambilivent to reasonable Rout amplifiers if in a properly selected diy box.
dave
One sub or 2?
With 2 subs (or 2 woofers) you can have a higher XO and what is often done is a small sealed enclosure for the midTweeter and active HP/LP. Potentially using the sealed 2nd order roll-off at the bottom of the midTweeter as all or some of the HP filter.
If you can cross higher an aperiodic midTL will help with mid/top DDR as one (tries) to suck all the back wave up in the TL.
With 1 sub you need the extention at the bottom of the mains and, REL style you are dialing the bass in below the range of the loudspeaker with only a LP.
2 or more works way better, for a number of reasons.
The CSS SDX10 is a favourite of mine, and goes up quite high for a subwoofer.
A11ms sealed sims attached. Suggests 5 litres or a bit bigger.
Keep in mind, that a reflex can often be made more suitable for this kind of use by putting a wool sock (i use a dense foam plug) into the vent.
dave
With 2 subs (or 2 woofers) you can have a higher XO and what is often done is a small sealed enclosure for the midTweeter and active HP/LP. Potentially using the sealed 2nd order roll-off at the bottom of the midTweeter as all or some of the HP filter.
If you can cross higher an aperiodic midTL will help with mid/top DDR as one (tries) to suck all the back wave up in the TL.
With 1 sub you need the extention at the bottom of the mains and, REL style you are dialing the bass in below the range of the loudspeaker with only a LP.
2 or more works way better, for a number of reasons.
The CSS SDX10 is a favourite of mine, and goes up quite high for a subwoofer.
A11ms sealed sims attached. Suggests 5 litres or a bit bigger.
Keep in mind, that a reflex can often be made more suitable for this kind of use by putting a wool sock (i use a dense foam plug) into the vent.
dave
Attachments
In the pdf plans, it is mentioned that bracing is recommended but it is not specified. So if I used the "holey brace" kind of bracing, should I use it parallel to top and bottom or do I use them perpendicular to the top and bottom and parallel to the sides?
Or, can I get away with not using any bracing?
Thanks.
Technically the holey braces are both longitudinal and lateral with the former also lightly coupling the motor structure. If you find them hard work (which they are), a window-brace or pair of window-braces with uneven distribution should suffice as this is not an especially large box. Not quite as effective, but better than none.
One of the rules for braces is that you aspect ratio of the subpanel is greater than the ratio of the original panel.
So if you look at Nostromo, brace 1 runs from front to back vertically just off centre (and braces the driver).
Ignoring the driver, the second would all be parallel to the baffle, but this breaks the even more important property of avoiding things that cause earlier reflection so in this case 2nd brace would be horizontal bracing the sides against the first brace. ie bothbraces end on in relation to the driver.
dave
So if you look at Nostromo, brace 1 runs from front to back vertically just off centre (and braces the driver).
Ignoring the driver, the second would all be parallel to the baffle, but this breaks the even more important property of avoiding things that cause earlier reflection so in this case 2nd brace would be horizontal bracing the sides against the first brace. ie bothbraces end on in relation to the driver.
dave
