Hello
I have a pair of Lowther DX55 that came from my rethm 3rd that got badly damaged during shipping. Now I am left with these magical drivers that I would like to either build or buy cabinets for, any suggestions on what type of horn or bass reflex cabinet to try? I want to stay with these drivers as I adore its speed and transparency.
Currently I mounted them on a neat acoustic cabinet which is not ideal at all. I use a Korneff 45 SET to drive it with Naim Audio pre and CD player. Love it!
Thank you in advance for your advice and suggestions, now back to the music
Ash
I have a pair of Lowther DX55 that came from my rethm 3rd that got badly damaged during shipping. Now I am left with these magical drivers that I would like to either build or buy cabinets for, any suggestions on what type of horn or bass reflex cabinet to try? I want to stay with these drivers as I adore its speed and transparency.
Currently I mounted them on a neat acoustic cabinet which is not ideal at all. I use a Korneff 45 SET to drive it with Naim Audio pre and CD player. Love it!
Thank you in advance for your advice and suggestions, now back to the music
Ash
If you want to run them solo, a horn is about the best thing to do with them, though they'd make an excellent wide-band mid / treble unit with a supporting woofer. The latter would have to be good to keep up though.
FWIW, a hyperbolic horn with an M=0.5 (according to GM, the ~optimal is around this point, and the models I've run concur)is probably as good a bet as any. However, a problem is that the Lowther parameters are a trifle 'optimistic' shall we say (i.e. so far out as to be almost valueless, if current evidence regarding the 8in units is anything to go by). So unless you know of some reliable figures, or can measure them yourself, you'll have to fudge it a bit. Select a throat CSA=0.25 - 0.5Sd, and plug this, the flare constant, and flare frequency into an applet like the one on the single driver site, then use this formula GM told me about a while back, and which I generally use when not using Leach's math to calculate the volume of the filter chamber:
V = (5.47/fc)*At
where:
V = volume of chamber in liters
Fc = upper corner frequency of the passband in Hz
At = area of the throat in cm^2
FWIW, a hyperbolic horn with an M=0.5 (according to GM, the ~optimal is around this point, and the models I've run concur)is probably as good a bet as any. However, a problem is that the Lowther parameters are a trifle 'optimistic' shall we say (i.e. so far out as to be almost valueless, if current evidence regarding the 8in units is anything to go by). So unless you know of some reliable figures, or can measure them yourself, you'll have to fudge it a bit. Select a throat CSA=0.25 - 0.5Sd, and plug this, the flare constant, and flare frequency into an applet like the one on the single driver site, then use this formula GM told me about a while back, and which I generally use when not using Leach's math to calculate the volume of the filter chamber:
V = (5.47/fc)*At
where:
V = volume of chamber in liters
Fc = upper corner frequency of the passband in Hz
At = area of the throat in cm^2
I suspect they'd be a bit big for the Fugel-Horns as-is. It's not exactly scientific, but it might work OK in a Level 0 build with the width boosted by 20mm. Of the Spawns Hiro would likely be the best bet as there's plenty of volume to work with. They'll probably be very boomy at first due to that, and excursion would be too high, so it'd be a case of strategically damping the enclosure to taste, just like it used to be when driver specs were not available to the DIYer. Anyone know of some accurate measurements for the DX55?
I can't say I'm entirely surprised the Academy lacks bass. How many drivers have you got -IIRC, the Academy uses two units per cabinet?
There are plenty of possible options that will work well, but which suits you best depends on what sort of cabinet, and what sort of sound you like (and can fit in your room).
There are plenty of possible options that will work well, but which suits you best depends on what sort of cabinet, and what sort of sound you like (and can fit in your room).
Thank you to all here, The baffle cutout needed for the DX55 is 14cm (5.5 ins).
I do not mind trying the to build a cabinet providing it is relatively simple, no fancy curves etc. Nelson's Kline horns are out of question for now at least as I am in small apartment. They do look like a fun project.
Are there any other plans of cabinet that would work well ?
The other alternative I am thinking is to just buy the commercially available Alerion
I am new to the single driver community but I feel in love with the sound of these dx55 even in a make shift installation in another speaker cabin, fast and very emotional. Later on I would like to try Nelson's first watt current drive....
Once again thank you for the help here for the newbie here.
Cheers
Ashok
I do not mind trying the to build a cabinet providing it is relatively simple, no fancy curves etc. Nelson's Kline horns are out of question for now at least as I am in small apartment. They do look like a fun project.
Are there any other plans of cabinet that would work well ?
The other alternative I am thinking is to just buy the commercially available Alerion
I am new to the single driver community but I feel in love with the sound of these dx55 even in a make shift installation in another speaker cabin, fast and very emotional. Later on I would like to try Nelson's first watt current drive....
Once again thank you for the help here for the newbie here.
Cheers
Ashok
I've had a pair of DX55 (one of my favorites) for several years and have tried them in two types of rear loaded horns and an oversized BIB. None of them produced a balanced sound (or enough bass for me). I finally realized that it is an oversized mid/tweeter. So, I front loaded it and put it on top of my 208ES rear loaded horn. For whatever reason this is the best I have heard the DX55, with or without EQ. I recently blew up my third pair of cones and am waitng for a replacement.
Yep, that's what all 'FR' drivers of 5in or smaller diameter are. Over that and they're glorified mid-bass units.
Ye Gods. If you're blowing cones like that, methinks you might want to take another look at the load -it sounds like there's far too much excursion going on. What frequency do you bring the Lowther in? Are you sure the sealed chamber to the rear and horn tuning frequency are consistant?
Actually, I think that would be an excellent application. Bring the Lowther in at about 250Hz and use a good quality 12in - 15in driver in either a scoop-bin or a large reflex cabinet up to about that point.
If just the DX55 is wanted in a back-loaded box, and nothing fancy -no front horns or extra drivers are wanted, then Hiro will probably have a better chance of working than a lot, as it's got plenty of length & volume, & the flare might suit (when I designed it, I started out with a ~catenoid profile) but you'll need to juggle the damping and back-chamber volume. The little DX is never going to be great at LF until you shift to a ~full-sized horn like Nelson's Kleinhorns, and even then, bigger is better. As Horst says, I'd expect things below ~300Hz to be a bit coloured.
Hiro
Yes I would like to keep it very simple and thus Hiro does appeal to me . Question for Scott and others: Is it is easy to redesign the length, flare and volume to make the hiro design better suited for the DX55 driver. Could Scottmoose's suggestion of hyperbolic horn geometry (see post 2 on this thread) be incorporated here. What information is needed to get started with the redesign?
Ashok
Yes I would like to keep it very simple and thus Hiro does appeal to me . Question for Scott and others: Is it is easy to redesign the length, flare and volume to make the hiro design better suited for the DX55 driver. Could Scottmoose's suggestion of hyperbolic horn geometry (see post 2 on this thread) be incorporated here. What information is needed to get started with the redesign?
Ashok
To make a redesign worthwhile, I'd need a complete set of accurate T/S parameters, and the problem we have is that to the best of my knowledge, there aren't any. I looked at the published information on the Lowther site, but I've never liked fairy stories much. Without it, we wouldn't really have a box any better optimised to the driver than Hiro already is. FWIW, as regards modifying the existing cabinet, I'd probably reduce the back-chamber volume by 1/3 and take that as a starting point. Theoretically, the horns will run up higher, but the multiple folds at the start of the expansion help attenuate most of the highs in practice, and it should reduce driver excursion.
It's the chamber the driver fits into, sometimes (incorrectly, as this is a back-loaded horn) called a compression chamber. You could shove a couple of sandbags into it, or add some plates that blank off some of the volume of the chamber. As I say, I'd probably start by reducing it by roughly 1/3.
You tune a cabinet by ear by listening to it and adding damping materials to taste in strategic locations. The chamber and throat areas are usually the places that are targeted first. Sometimes a layer of foam around the mouth can be of help. If too many highs are escaping through the mouths (unlikely, given the multiple folds in the initial expansion, which should attenutate them), then a piece of thin BAF wadding across the final vertical paths before it makes the final forward expansion to the mouths will probably sort this problem while preserving the bass frequencies, where the wavelengths are too long to be worried.
You tune a cabinet by ear by listening to it and adding damping materials to taste in strategic locations. The chamber and throat areas are usually the places that are targeted first. Sometimes a layer of foam around the mouth can be of help. If too many highs are escaping through the mouths (unlikely, given the multiple folds in the initial expansion, which should attenutate them), then a piece of thin BAF wadding across the final vertical paths before it makes the final forward expansion to the mouths will probably sort this problem while preserving the bass frequencies, where the wavelengths are too long to be worried.
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