cabinet for a lowther ex4

[mjkempton]

All

I'm treating myself to a pair of Lowther EX4's

Opinions on cabinets please.

I'd prefer a room friendly cabinet BLH fine, but no front horns.

I'm looking/listening for midband transparency, detail and speed. An impression of bass weight but not shaking the window frames. I've never felt comfortable with sub woofers - never heard one that didn't spoil the rest. I've been using 215 RTF 64 Bicones in very simple quarter waves as per the Supravox design.

Best friend has DX4's so I'm very familiar with the Lowther sound, and, umm, I like it!

Best sounding Lowther I ever heard was the Carfrae Big Horn - absolutely stunning but waaaay to big.

Music taste is everything - no real preferences.

Other equipment: PC based to a Behringer ULTRACURVE PRO DEQ2496 to two Flying Mole DAD-M100 power amps.

Room is 1950 cubic feet or 15x13x10 and I listen down the 15ft length.

Would Martin's Project 04 for the DX4 be suitable ?

I'm not fazed by woodwork.

TIA

Jim

[Scottmoose]

Well, if you want something relatively compact, then yes -Martin's MLTL is going to be a very good best. You can always try something else like a hybrid BLH later, should you feel the need.

[mjkempton]

Thanks for confirming that for me Scott. I like the look of the plots for Project 4.

In your opinion what improvement could I expect from a BLH, hybrid or otherwise ? And any design suggestions ?

TIA

Jim

[Scottmoose]

Well, you'll get higher sensitivity, & superior dynamics over an MLTL. Scale is also a strong point due to the sheer quantities of air the driver is coupling to. As for designs -there are loads around, but not many of them really float my boat. Avoid the Acousta like the plague -it's not terrible, but there are far better boxes out there. BTW, just about every domestic 'horn' is really a hybrid -full-scale bass-horns would need a mouth with a CSA of about 200ft^2 to get down to the mid 40Hz regions.

I've got a design for the EX4 in the works at the moment ironically enough, though it might not be entirely to your taste as it's a double-mouth cabinet, with over-under mouths a la Terry Cain's BENs. Got a couple of corner-horn ideas too, but they're further down my to-do list.

Cheers
Scott

[mjkempton]

Ex4's bought 6 weeks ago. Cabinets finished Friday, no they didn't take that long! I only started 2 weeks ago due to work pressure.

I went for Martin's Project 4.

I used external grade, void free 19mm ply. Jointed with biscuits and plenty of pva glue and left in clamps for 48 hours.

Haven't had too many hours in front of them but impressions so far:

Good points.

even response from about 100Hz up
minimal overhang, hence "fast" sounding
loud enough for anything I'll play
plenty of detail, famlar recording throwing up new insights

Not so good points.

A bit thin sounding
Lack of bass weight - though it is articulate and easy to follow
Perhaps a bit hot up top, too much sibalance on voices.

I'm hoping these negatives will improve/disappear as time goes by. Anyone got a definitive time for break-in ?

Have put the Behringer 2496 into bypass for now, so just acting as a DAC from the PC. I'll leave it this way for a few weeks before I apply some correction EQ.

Raw, unfinished cabs just now. Will veneer them soon and post pics.

Jim

[GM]

You'll need to add MJK's adjustable BSC ckt. to dial it in initially and periodically trim it as they break in. Understand though that these are essentially near-field monitors due to the driver's minimal low distortion excursion capability.

[Scottmoose]

As Greg says, you'll need Martin's BSC circuit in place or things are going to sound thin as without it you're going to be loosing between 3 - 6db below about 400Hz.

The highs (the cabinet doesn't really affect those, though re-balancing the sound with the BSC circuit will help considerably) should loose some of their sting with break-in. Thrash them for a week with Mahler, Iron Maiden, prog-rock etc, which should loosen them up nicely. You should find things much more listenable after these are done.

[steve shiels]

Originally posted by mjkempton

even response from about 100Hz up
minimal overhang, hence "fast" sounding
loud enough for anything I'll play
plenty of detail, famlar recording throwing up new insights

Not so good points.

A bit thin sounding
Lack of bass weight - though it is articulate and easy to follow
Perhaps a bit hot up top, too much sibalance on voices.

I'm hoping these negatives will improve/disappear as time goes by. Anyone got a definitive time for break-in ?



.

Jim

Hi Jim, i use the same driver,

i have never had any issues with sibalance.. getting an amp/ source good enough for them is another thing...

i use old british triodes and very good output transformers.. the lowthers really show the benifits of a good signal into them..

I used them BLH's for quite a few years and got a a good result with the bass output, gettiing a balanced sound too
but they are quite big.. 3.6m into a biggish mouth into the corners...

mine are on the world designs forum gallery

I now use the drivers in baffles as a mid/tweeter.. where it sounds even better... to me

they are hard drivers to get the best from them...but worth the time and effort


steve

[mjkempton]

Thanks to Scott, GM and Steve for the replies.

Is the BSC circuit/filter *just* for frequency compensation ?

If so I think the Behringer will do the same, i.e. it will listen to and measure the speakers and room and apply a corrected curve to be sent to the amps. I've used this successfully for at least 5 pairs of speakers and it always delivers. I understand some folk have expressed some concerns but I've never heard the negatives.

If it's not then what else does it do ?

Please wait just there while I put my asbestos suit on.......... OK now I'm ready.

I've never got on with valves/tubes, they've always sounded too soft to me - clearly I've not heard valve amp there is. Just my limited experience forming that opinion.

Jim

[Scottmoose]

Yes, it's there as frequency compensation, cutting all frequencies above the baffle-step point by an appropriate amount (usually 3 - 4 db), while the zobel compensates for the inductive rise of the driver.

If you use DSP, I'd suggest the same approach: cut everything above the baffle step point rather than try to boost the LF, or you'll run into excursion problems.

Tubes don't have to sound soft -the problem is almost always mediocre output transformers. Most commercial manufacturers simply don't use especially good ones for cost reasons.