Awesome stuff Earl, and thanks for the feedback.
Yeah those Garnet rigs are really getting some traction in the collectors market, especially their tube stuff.
Yesterday I got some negative feedback from a well respected engineer over at the TB forum that I'm still trying to process.
His area of concern was the minimum impedance at 5.4 ohms and the flat impedance curve above that. I'm stumped because I thought that would be a good thing.
Now, I'm pretty sure I'm not so sure about all this.
He really, really disliked the zobel which I'm using as a filter to clean up the 4db spike the 3015 has between 1100 and 2200.
Yeah those Garnet rigs are really getting some traction in the collectors market, especially their tube stuff.
Yesterday I got some negative feedback from a well respected engineer over at the TB forum that I'm still trying to process.
His area of concern was the minimum impedance at 5.4 ohms and the flat impedance curve above that. I'm stumped because I thought that would be a good thing.
Now, I'm pretty sure I'm not so sure about all this.
He really, really disliked the zobel which I'm using as a filter to clean up the 4db spike the 3015 has between 1100 and 2200.
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Gord
Your amp is stable to 2 ohms, so the expressed concern about a minimum Z of 5.4 ohms shouldn't be due to amp stability issues, so I don't get the concern.
Zobel, well you might find it robs a bit of dynamics > this you'll need to determine by ear.
- You can always raise ( double ) the value of that Zobels resistor > so "Flattening" at a higher Z value + also by extension , redirecting a bit more current/voltage towards woofer usage ( & less from heating the resistor ) .
🙂
Your amp is stable to 2 ohms, so the expressed concern about a minimum Z of 5.4 ohms shouldn't be due to amp stability issues, so I don't get the concern.
Zobel, well you might find it robs a bit of dynamics > this you'll need to determine by ear.
- You can always raise ( double ) the value of that Zobels resistor > so "Flattening" at a higher Z value + also by extension , redirecting a bit more current/voltage towards woofer usage ( & less from heating the resistor ) .
🙂
I don't recognize your plots. Did you check excursion? Seems unusual that you tuned for flat bass extension and excursion was OK: bass cabs are different animals.
Using WINISD, the excursion is fine at 3 c.f. and 46 Hz. This amp also has two stages of high pass filtering - a fixed two pole at 22 Hz and a variable 2 pole up to 150 Hz.
Modelling 400 watts there is 6.3mm peak excursion at 73 Hz, with no high pass filtering applied.
Xmax is 5.9 mm, and roughly double that for xlim.
I can't see ever using 400 watts rms with this cab.
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I gotta go back to the drawing board. I checked my driver tab and my impedance for the midrange was default flat 8 ohms. I used the enclosure tool to sim the chamber and found a glaring error.
Thanks!
Thanks!
Update - crossover help
I changed the value of the low pass inductor and caps. Here's some new graphs.
Amp/cab/bass tested yesterday. Sounds pretty good, very smooth and seems to be an easy load to drive. (based on volume knob position) With the old crossover I had to turn up well past noon on the master and with this one it gets plenty loud at around 11 o'clock.
Slight discrepancy between vituixcad impedance plot and measured dats values - VC plots 6.4ohms at @1700 hz while dats shows 6 ohms.
Questions are:
Is there anything I should change?
What's my next step?
I changed the value of the low pass inductor and caps. Here's some new graphs.
Amp/cab/bass tested yesterday. Sounds pretty good, very smooth and seems to be an easy load to drive. (based on volume knob position) With the old crossover I had to turn up well past noon on the master and with this one it gets plenty loud at around 11 o'clock.
Slight discrepancy between vituixcad impedance plot and measured dats values - VC plots 6.4ohms at @1700 hz while dats shows 6 ohms.
Questions are:
Is there anything I should change?
What's my next step?
Attachments
Looks good Gord.
I would try swapping the polarity of the mid ( to be positive ) while auditioning the change with your bass as a source.
Clearly the crossover area won't be as seamless as what you've shown > but it wouldn't surprise me if one preferred the sound of all transducers making music while going the same direction.
🙂
I would try swapping the polarity of the mid ( to be positive ) while auditioning the change with your bass as a source.
Clearly the crossover area won't be as seamless as what you've shown > but it wouldn't surprise me if one preferred the sound of all transducers making music while going the same direction.
🙂
Nice. It's worth a try to swap polarity, as I don't have any response plots to work with, and the worst thing that could happen isI don't like how it sounds and switch it back.
I do have a tweeter, it's an APT80, an eminence 5k 2nd order crossover, and a variable lpad attenuator.
This is also an option.