No I don’t but unless you do this actively this is really hard to do. And I don’t see it implemented in commercial designs. And besides that I’m not the OP so I don’t know what he’ll do.
My whole point was to prove that even for a SPL that hits xmax at a frequency ***above*** the tuning, you don’t need a 19 cm port.
Ralf
My whole point was to prove that even for a SPL that hits xmax at a frequency ***above*** the tuning, you don’t need a 19 cm port.
Ralf
Not really. I have one in the FX loop on my bass guitar rig etc. Can't comment on every system implementation.
So another reason they use undersize ports to compress and reduce output below tune, as well as above it at high SPL. Besides, are you, as in a DIYer, restricted by commercial limitations?
Posting charts, really easy to export from Unibox, would make it easier to see the point you're trying to make.
Having measured thousands of drivers, if you have a variation of 10% (ie ∓5 ) actually represents a driver that is manufactured to very high tolerance standards. One can get 10% just from the same driver depending on the dynamic conditions. it can change that much just playing music.
dave
If I understand correctly, this is an active implementation. As I said, a LP filter at 40Hz is easy if active, and a nightmare if passive. But not everyone can have an active solution. Again, I'm not the OP and can't comment on what he wants to implement.
Ralf
PLLXO. Only passive components, just on the input of the (power) amp. I get how difficult it is to do between amp and speaker, but there are other approaches. Even as a full line level active, it's still easier and cheaper.
I don't think I have ever run one of my own ported designs without HPF protection; to do so when there is a chance of modest to high signal below tune is just foolish.
None of the commercial speakers I dismantle have ports matching any online calculator spec and none of my diy builds now follow calcs as some (reputable authorities) differed by 100% on port spec. May I suggest using a dowsing rod / pendulum or waiting until you get a 'feeling' for the measurement. This usually defeats scientific approach and provokes amusing argument.
Were Einstein to have been a diy speaker builder I'm surely uncertain he'd support this belief, after his Dice debacle at least.
Were Einstein to have been a diy speaker builder I'm surely uncertain he'd support this belief, after his Dice debacle at least.
^^ What a load of hyperbolic nonsense. Not once, ever, have any of my designs either calc'd longhand or using my preferred sim, Unibox, come out more than a few % and I'd put that down to airflow around the extensive bracing I use or driver T/S parms being off. This applies to both domestic and PA enclosures I've designed and built.
As I've already noted, I prefer tubular ports and measure to confirm tune. That's how I know they're correct.
As I've already noted, I prefer tubular ports and measure to confirm tune. That's how I know they're correct.
No argument about tubular ports from me. However your described verification of tune by measurement is a manifestation of confirmation bias and overlooks the sensitivity of tune to port length. In other words you need to also measure an over-length and an under-length port to see how far it affects the speaker system alignment. You most likely already have an empirical knowledge of this, in which case I respect your experience.
^^ Yes John, I set the lengths long, then adjust back and forth around tune by adjusting length until I'm happy it's correct by measuring both FR and Z, though the latter is the most use. Much easier to do this with tubes for small size runs.
Thank you for the input ! Very Educating. I'll go working with the simulators. Super feedback.