[Retsel]

You may still bottom out those drivers from time-to-time as 12 inch drivers are not very big.  Rather than highpassing those drivers, you could simply add more drivers so that each individual driver does not need to work very hard.  This will reduce overall distortion, and reduce doppler distortion as well. 

For my open baffle bass, I use a pair of 18 inch drivers and a pair of 15 inch drivers (one each per side).  As you can imagine, the drivers hardly move, even with the most demanding bass, and there is virtually no sound compression.  This also reduces the stress that each driver places on its baffle, which helps to reduce noise and flexure from each baffle, again reducing distortion. 

Retsel

[jkelly]

Now we're talking - any chance you can post a pic of those bass drivers?

Jeff

[Jon L]

Still very early on for my Lowther/TT open baffle combination, but, the TT's appear to be fairly limited in power handleing.  They are bottoming out before the Lowther/ 2 watt set combination reaches it's volume limit.  I think that either The TT's will require a much larger baffle, or their bass reach will need to be curtailed.   

Ah, gotta love the 45SET's with Lowthers.  Using EML 45 solid plates? 

I've tried for years to match my active biamp speaker's top and bottom, and the amps used for both sections are very important.  Have you tried a *really* nice SS amp for the bass instead of the plate amp? 

[JoshK]

one thing that gary pimm demostrated, was that the input capacitance of a plate amp or an electronic crossover can interact with the upper frequencies as well.  you don't just hear the quality of the upper amp, you also hear the input of the lower amp as it is in parrallel and affects your preamp and signal too.   that is a fairly poor way of saying what i was trying to say.

[richidoo]

Interesting Josh - thanks

[JoshK]

The point I think is you should buy a nice amp for the lows, rebuild the input stage or properly buffer the low pass outputs from the rest of the system.  I personally like the last option as it is easy enough to do and solves all potential matches.  The second is quite plausible too.  The first is the lazy and expensive way IMNHO.

[scorpion]

Chopper87,

Now when Bass frustration has gone, deep bass wouldn't be there anyway, couldn't you give us some input on the TTs used as midrange - fullrange. That would be most welcomed ! 

/Erling

[Chopper87]

First, my current plan is to replace the Bash plate amps/xovers with a nice EL84 PP amp with around 14 watts.  Of course I will then need a pair of passive low pass crossovers (I will need help here guys) at probably between 150-200 Hz to blend with my Lowther PM2MKII's.  Now, before I get to that point I will run the TT's full range next to Lowthers to hear if there is an obvious volume disparity between them.  If so, then I will likely stick with the plate amp/xover with it's volume control.  Things may not be so simple though.  The Lowthers may be several db's higher in efficiency,but, at around 200 Hz and below they are likely down more than several decibles from their specified efficiency while the TT's may well maintain their rated efficiency at those frequencies.  It would have to be pure luck (or baffle size maniplation) for these different drivers to just happen to volume match naturally at 200 Hz but I am hopeful.  I assume that the TT's will drop a couple of db's through a passive filter so I am hopeing that they are somewhat louder than the Lowthers at 150-200 Hz.  Any way, I reeally would like to go the tube amp/passive route rather than the current compromise of an inexpensive plate amp.
Also, I have become sickened by the often overblown bids for Ebay amps such as 6BQ5 eico, pilot, fisher, Dynaco  amps etc.   If any  one has such an amplifier that I may acquire at a fair price it would be greatly appreciated.  I wll of course need 150-200 Hz tones because there is no way to compare their volume levels without strictly narrowing the sound to them.