At Parts Express. Hunt down parts 276-152 and 296-145 and you'll find the AP100Z0 for $19 and the TM025F1 for $13. Still not as cheap as the $15 and $7 they had a while back, but generally a good deal.
These are used in the design I just posted.
Audax Mini
Tuning options have been discussed in that massive thread about the Maplins coseouts, but I've come to the conclusion these sound better sealed. The group delay is too noticable at the tuning frequency otherwise. I choose to have less bass if I can have it cleaner.
Regards,
John
Ps. I recall Madisound matching PE's pricing on some sale items before, so if you'd rather deal with Madisound, ask them about it. They have the woofer on sale for $19, but the tweets are not on sale. Also, raid Madisound's cap and coil specials. The steel laminate 1.6mH's become 1.5's with 3 turns unwrapped.
These are used in the design I just posted.
Audax Mini
An externally hosted image should be here but it was not working when we last tested it.
Tuning options have been discussed in that massive thread about the Maplins coseouts, but I've come to the conclusion these sound better sealed. The group delay is too noticable at the tuning frequency otherwise. I choose to have less bass if I can have it cleaner.
Regards,
John
Ps. I recall Madisound matching PE's pricing on some sale items before, so if you'd rather deal with Madisound, ask them about it. They have the woofer on sale for $19, but the tweets are not on sale. Also, raid Madisound's cap and coil specials. The steel laminate 1.6mH's become 1.5's with 3 turns unwrapped.
Re: Re: Audax on sale again...
Good catch, the Madisound sale item is not shielded. Also, it's specs are different enough that it looks like it won't work in this design. Everyone who wants to use this crossover should stick to the shielded woofers.
Looks like the non-sheilded version has more magnetic strength with the resulting changes in parameters - higher efficiency and lower Qts. Low efficiency is a sore point of the shielded version.
I'll have to update my web page when I get home to make sure people use the shielded version with my design.
John
Zaph said:
jackinnj said:
Good catch, the Madisound sale item is not shielded. Also, it's specs are different enough that it looks like it won't work in this design. Everyone who wants to use this crossover should stick to the shielded woofers.
Looks like the non-sheilded version has more magnetic strength with the resulting changes in parameters - higher efficiency and lower Qts. Low efficiency is a sore point of the shielded version.
I'll have to update my web page when I get home to make sure people use the shielded version with my design.
John
Re: volume adjustment?
No change, I use that enclosure sealed. It measures out to a box Qtc of .66 after everything is in place. It could probably be made a little bit smaller with no ill effect.
People don't realize how sloppy and loose a high qts woofer can sound when used in a vented alignment. Group delay is terribly audible.
sberube said:
No change, I use that enclosure sealed. It measures out to a box Qtc of .66 after everything is in place. It could probably be made a little bit smaller with no ill effect.
People don't realize how sloppy and loose a high qts woofer can sound when used in a vented alignment. Group delay is terribly audible.
Vikash said:
Group delay -- the nemesis of filter builders -- in audio it can cause voices to blur or spread out and pianos to sound very unnatural -- i think that the voice and piano are the two great devices for listening tests.
The speaker, its box (and all the dimensions therein) or the alignment are all a "physical filter" -- the great advance that theile-small did was to transform the physical aspects into electrical aspects which could be modeled.
jackinnj said:
That's exactly right. Unnatural is the word that describes it best. Basically, the harmonics don't properly line up with the fundamental, and the result is slop. It's easier to hear it with high tuned, high Qts woofers because they will sound fine until the bass player hits that note at the tuning frequency. It will stand out like a sore thumb. Or worse yet, the music has a beat and that beat is at the tuning frquency. Honk honk honk.
It may measure flat with a sine wave, but it's still going to sound like one-note bass.I like vented enclosures, but in general I prefer them with lower Qts woofers, and the tuning frequency lower and out of the primary musical spectrum. Like tuned 35-40hz or lower. Or I bend that rule occasionally with different woofers, such as very low Qts small woofers, or larger slightly high Qts woofers that can make use of a very low tuning frequnecy.
An externally hosted image should be here but it was not working when we last tested it.
Vikash said:
Well, lets pick an instrument, say a kick drum. The primary tone (fundamental) that comes out of it is 60hz. But the kick drum also has harmonics all over the spectrum. probably some at 120 hz, some at 1500hz and even higher. If there were no harmonics, it would just be a simple sine wave.
If there is 20 ms group delay at 60hz, the fundamental is going to be slightly delayed in comparison to the harmonics, resulting in an unnatural sound. For higher frequencies, jackinnj's description fits well. At lower frequencies it can be described as sloppy and undefined.
Large kick drums are usually centered on 60hz, and the lowest string of a bass guitar is around 40hz. There are fewer harmonics in a bass guitar than a kick drum however. In general, I think you can get away with higher group delay as you move further away from the music spectrum. If I had to put a number on it, I'd say under 10 ms at 50 hz and under 12 or 14 ms at 40 hz.
This is often hard to do with a vented alignment, and I often chose a non-optimum box size for vented. I still prefer vented over sealed, but only with larger woofers. I rarely vent any drivers under 5".
See this thread over at the mad forum for an idea about non-optimum enclosures and group delay.
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