distortion at 5029Hz/103dB was less than 1/4 of one percent  - didn't experiment enough to figure a highpass which would flatten the bottom bump/or
use as super-tweeter.  Martin's graph looks reasonable -other than the dip frequency ! -  -lets see a Goldwood

......................Blake

Anyhow, this sounds like a case of trying to make a horn driver sound good in a vented box (whatever a promo type box is ??) by coating it heavily. IIRC the last thing you were building was a BR. It would be better to use a more appropriate driver to start. Which is I suppose what you are asking...

I'd say one of the Mark Audio drivers is a good bet. The Fostex FFxxxWK series is although worth a look. The specs have been modified to make them optimized for bass reflex, though some may require an RC filter or EQ to get flat freq response.

For sealed, you just cover the back of the driver with cheesecloth.

GM

Got Pics ?

I'll be sure to take some underway, the drivers are beeing shipped from the states, so it should take a while to reach me.

Unless there's some new proof to the contrary, we can only discern about 1/6 octave resolution, so see no need for anything higher.

GM

My brain barely works so I'll go with 1/6 too.

this MLTL pipe only had 1.25" bonded Dacron lining on four walls and top - if I put a new whizzer/dustcap* on one B102 then will use some fill from top down to around tweeter height.  (when B102's dustcap was removed and an anti-cavity resonance plug inserted, some things smoothed but it was a bit dull - could be the helper xover being too high)

Outdoors LF performance with old model B102.  Sampling 8K.  note the ground plane response. I think that would look similar if the mic were pretty far away
and something we may not see in some sims. 

A Sd crossection pipe vented to floor boundary is one way to do things.

one thing interesting was how BOFU/B20 behaved in that pipe vs the old model B102 - look how weak B20 performed on the low end. The 10" did much better
plus had much more power and control.

I had an APT80 copy - lol - the off axis response was much like Soundstage's graph of the early Druid and perhaps why some don't like wideband
with helper.

overall my fake Druid was very good when tweeter was tweaked and the design quite cool - it had good power handling in a nice form-factor.

-there's a chance W8-1772 might "beat" AN8 on the top but I'll have to enlarge the hole on the adapter ring to find out.

Of note on the SK8 graph I posted above is that reducing the vent area to tune lower made the first dip wider and deeper, so it seems like the larger area to provide some "fill" as you say could be useful.  It's good that you don't need much length for a pretty large vent area to tune low in there.

IG

If the driver is placed off center in a larger cylinder, that should be fine.

$399 /pair speakers with $39/ea drivers is not bad. Oftentimes you'll see $3.99 drivers in that range...

See post 97 for pics.

Kensai is the guy who has these. If you read through his posts in that thread, he talks about their performance and how much EQ he used.

...........................Blake

The Olivia design is almost 5 yrs old, and he's made rather quite a bit of progress / improvement in his design catalog.

If "in the process" means you've already made some sawdust,  or even proceeded further, then I can attest from personal experience that the FF125WK could well be considered a drop in replacement (arguably upgrade) from the FE127E for which Olivia was designed - I'd stick with them.

Even if the lower stepped deflector were fabricated from steel plate or cast in concrete, these will remain tippy enclosures - particularly on carpet,  so a wide mounting plate (say 12x12" or more)  should be considered mandatory.

For the intended purpose of rear ambience fill, a simple tweeter such as FT17H with 1st order cap filter somewhere around 8kHz should be fine, and wouldn't hurt a single stereo amp, but there's no reason you couldn't bi-amp with appropriate HP filter.  It probably wouldn't be much trouble to use 12" material and mount a small driver inside the wedge deflector on the backside