I was given a pair of Lowther Fidelio cabinets a while back. To be fair, they were on their last legs, the veneer was f%&Ked, two dead mice inside and to be honest, should have been torched if it was not for the fact that this thing weighed a tone and was rock solid!
This is my first BLH speaker project, being a tight ****, I wasn't willing to buy some Lowther Drivers. Instead I decided to opt for a vintage pair of FR drivers which I had measure and sim'ed to see what changes were required for the enclosure.
Due to being lazy, I have mainly stuck to half-wave rear absorbing enclosures, IE they sim and measure like a "true" IB design. So it was a bit of a shock to me when I saw the results after sim'ing and comparing both my vintage drivers and a pair of Lowther EX drivers. Though they both sim'ed with a lot if similarities, I have to be honest I wasn't prepared for the mess a back loaded horn produces.
Sim's complete and armed with my master plan of how to tame this beast, I had one more little test I was intrigued to find out. How true is a Sim. compared with real life measuring -
In fairness the comparisons where okay.
The build continues and nearing completion. There are still a few mod's I'm looking to introduce. Will do an undated including measurements soon.
If anyone is interested in my past builds, experiments etc see www.facebook.com/SparrowLegsSpeakerDesign
This is my first BLH speaker project, being a tight ****, I wasn't willing to buy some Lowther Drivers. Instead I decided to opt for a vintage pair of FR drivers which I had measure and sim'ed to see what changes were required for the enclosure.
Due to being lazy, I have mainly stuck to half-wave rear absorbing enclosures, IE they sim and measure like a "true" IB design. So it was a bit of a shock to me when I saw the results after sim'ing and comparing both my vintage drivers and a pair of Lowther EX drivers. Though they both sim'ed with a lot if similarities, I have to be honest I wasn't prepared for the mess a back loaded horn produces.
Sim's complete and armed with my master plan of how to tame this beast, I had one more little test I was intrigued to find out. How true is a Sim. compared with real life measuring -
In fairness the comparisons where okay.
The build continues and nearing completion. There are still a few mod's I'm looking to introduce. Will do an undated including measurements soon.
If anyone is interested in my past builds, experiments etc see www.facebook.com/SparrowLegsSpeakerDesign
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Philips 9710.
With regards to sound, its okay I guess... they're still not finished, more stuffing required. Also I want to experiment with the waveguide mouth piece as I'm a little skeptical about the whole concept.
Did you include the Helmholzresonators in your sims? The Fidelio is a... Fairly atypical backloaded horn. I think it takes the art of trying to save lethal limitations very far. I built a pair of related horns, the Bicor 200. Interestingly, it sounded thin but somewhat balanced with Lowther drivers. With frequency sweeps it became apparent that the bass was just a strategically placed peaks and dips. Just enough bass to support the illusion of bass. With a 12cm fullrange driver (qts 0.5) the horn did much better, deliver fairly constant and even bass with the trademark horn punch. The fidelio is similar in form, but is larger and most of the space seems to have been used to add these helmholtzresonators. Trying to refine the strategic dispersion of peaks and dips?
Bert Doppenberg of BD-design said it was ok. Bass to about 50 Hz with a Lowther driver, fairly even response. I know someone who replaced klipschlike cornerhorns with these, says it started to sound good only after finding the right phaseplug to disperse treble and reduce midrange.
There are much more modern designs (Woden, Spawn of Frugel, designs from the German magazine Hobby Hifi) that will change your mind about backloaded horns. If you want to stick with this horn, trying different drivers and EQ will probably help a lot.
And if you google for old threads and websites about taming Lowthers, there is a lot of good info there.
Bert Doppenberg of BD-design said it was ok. Bass to about 50 Hz with a Lowther driver, fairly even response. I know someone who replaced klipschlike cornerhorns with these, says it started to sound good only after finding the right phaseplug to disperse treble and reduce midrange.
There are much more modern designs (Woden, Spawn of Frugel, designs from the German magazine Hobby Hifi) that will change your mind about backloaded horns. If you want to stick with this horn, trying different drivers and EQ will probably help a lot.
And if you google for old threads and websites about taming Lowthers, there is a lot of good info there.
Just an update really, I thought the Fidelio's needs an update. Made an additional tweeter. Did the trick, just a shame it does't go down below 80hz!
Don't know why I'm bothering to share... - Sparrow Legs Speaker Design | Facebook
Don't know why I'm bothering to share... - Sparrow Legs Speaker Design | Facebook
An externally hosted image should be here but it was not working when we last tested it.
Yes they have been modified, but not by me. This was how I received them. In fairness I have to say the change in whizzer/cone look to have been professionally done, though many years ago.
Noce work. I wonder if hot bass extension might be related to impedance of amp. Looks like a bank of (SMSL TPA3118's?) and perhaps this driver needs a high impedance amp? I sim'd the fidelio a long time ago and seem to recall at least 60Hz extension. Can't remember driver but probably a Lowther it was designed for. Try adding a 8ohm power resistor in series with amp and see if that helps bass extension.
Nice work on the cabinet! Is that an Omni tweeter underneath the onion domes on top?
Nice work on the cabinet! Is that an Omni tweeter underneath the onion domes on top?
Amps are fine, there Amptastic MINI-'1, 4ohms. To be fair I've measure the FR driver at 5ohms, as well as swapping to various 8ohm amps.
I too has simm'ed this cabinet, and tried every FR driver under the sun, evening with a Lowther driver, I've never been able to get 60hz???
Cheers for your positive comments about the work, yes the tweeters are omni, here is a close up picture.
An externally hosted image should be here but it was not working when we last tested it.
The meridian gore panels (petals) are the "tweeter radiators". Connected at each end to a motor, (2 motors per globe). Heavy stuffing inside the globes and they are capable of 4 to 18Khz.
Now this maybe the interesting part, i'll admit that I use a MiniDSP (not ever hidden the fact). Though I use this as a XO, the main purpose is to do with rephasing.
After many many experiments, I always experienced poor sensitivity (as does MBL), however like a chladni plate experiment, I came to the conclusion that the nodes forming on each petal was a contributing factor for this issue. by manipulating the phasing of the motor's, I have been able to boost the sensitivity significantly.
Over all, they work well, actually the more tweeking I do, the better the outcome.
There was an ethos which I was trying to achieve, here is the link if interested. The text should be on the right hand side.
More pictures are in the comments.... - Sparrow Legs Speaker Design | Facebook
More pictures are in the comments.... - Sparrow Legs Speaker Design | Facebook
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