I just ordered the 3mH coil and another set of FR58EX's as I am currently using them on an open baffle in one of the bedrooms (flower petal OB). It will be good to see this speaker up and running again with passive XO. I think this will make a great set of kitchen or bedroom bookshelf speakers. I have had the AC130F1's in a box for way too long.
I think I finally got things wired correctly. I always get confused with the reverse polarity. I have my one speaker wired up listening to Doc Watson and Dave Grisman. It is really clear and full. Thank you for your help and encouragement. I had to go thru 3 different amplifiers and 3 sets of measurements before I got something that looked right. I will order another FR58EX soon and try to do some better cabinets. I am happy with the sound quality.
Great!, you are very welcome!
Any photos of what your speaker looks like? Is the XO currently just point to point or maybe even just alligator clip wires?
This is encouraging as I am hoping these old Boston HD5 cabinets will once again find life. I am certaing they will sound better than the HD5 ever did.
I am getting the 3mH Dayton and going with the 2nd XO at 1kHz. Did you go with 600Hz XO?
I had all the parts for the crossover at 1000hz so I went ahead and just twisted it up and have it laying on top of the box like about 50 speakers here in my basement. I make most of my cabinets from pine so they are pretty rough but I use them over many times. This one was a Continuum in a previous life, now with a new front. I will take a picture and see if I can post it. I also want to thank John Hollander over at Parts Express forum for his guidance.
I did use a separate chamber. I started with an orange cone about 9" tall but I thought it was too large so I used a plastic cup about 6" high secured to the baffle with Gorilla glue. The pine boards only require cross cuts so it makes this easier. I really don't have a shop.
I assemble on my kitchen table.
I assemble on my kitchen table.
My Parts Express order showed up today - I got a new pair of FR58EX and some 3mH inductors and a few resistors. After scrounging by bench for poly caps, and a large 47uF bipolar, I put the XO's together. They aren't pretty but I did not want to solder them too tightly in case I needed to change a component. I opted for an R2 value of 2ohms to bring the highs a little more into the foreground. I am using the 1kHz crossover otherwise.
Crossovers (I can move the parts over to the new FAST XO PCB when I get those in):
Here is the XO PCB from the 10F/RS225 FAST speaker that will work here too:
Listening to them in the lab:
Closeup of the revived Boston HD5 cabinet now fitted with AC130F1 and FR58EX and a nice XO. Listned to a fe tracks so far - it is late so I will have to resume tomorrow at higher SPLs but what I hear so far sounds very good. Nice balance - similar to my big 10F/RS225 FAST but not as loud of course.
Crossovers (I can move the parts over to the new FAST XO PCB when I get those in):
Here is the XO PCB from the 10F/RS225 FAST speaker that will work here too:
Listening to them in the lab:
Closeup of the revived Boston HD5 cabinet now fitted with AC130F1 and FR58EX and a nice XO. Listned to a fe tracks so far - it is late so I will have to resume tomorrow at higher SPLs but what I hear so far sounds very good. Nice balance - similar to my big 10F/RS225 FAST but not as loud of course.
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Measurements
I have not taken out the UMIK-1 microphone in a long time. Here are some measurements of this speaker at 0.42m distance, coaxial with the tweeter. I am using my new Alpha Nirvana Class A amp, and an SMSL Sanskit 10 DAC for the output. Excitation was 1.64Vrms (0.33 watt). I took another measurement at exactly 0.5m and 2Vrms which indicates typical sensitivity for 2.83vrms at 1m just to have that data point for the record. Looks like this speaker box is a bit undersized and causes a large midbass hump which can be seen as a pressurization oscillation in the impulse/step function. A larger cabinet is needed for ideal operation. The pressurization causes higher distortion in the AC130F1 (a known problem) so ideally, a larger box will sound cleaner at lowe frequencies. Above 150Hz, this speaker shines relative to distortion. I am not sure why the Continuum, a well regarded speaker using a similar box size doesn't have any distortion complaints at lower frequencies? Also looks like the 2ohm padding resistor is uneccessary, although here a slight downward tilt can be pleasing. The 1kHz crossover integration though looks very smooth and I am pretty happy with that - it does sound quite good there. There is a definite aluminum breakup peak near 10kHz though. So not the smoothest driver at highs but has some characteristic aluminum cone "zing" to the sound.
Frequency Response (red is 1/8th cycle freq dependent window (FDW) and blue is unsmoothed):
Distortion:
Impulse and Step (UMIK has inverted response - large step should be positive):
Compare with Reference 2Vrms and 0.5m data (green) to show SPL sensitivity at usual 2.83Vrms and 1m standard:
So the takeaways are: larger box, reduce padding to maybe 1ohm or 0.51ohm resistor, maybe make as a TL for deeper bass with less distortion. But XO balance looks superb.
Manufacturer recommends 0.3 cu ft vented for 70Hz F3. For sealed, they recommend 0.13 ft cu which is very close to what I have.
Aurum Cantus AC-130F1 5-1/4" Woofer
I have not taken out the UMIK-1 microphone in a long time. Here are some measurements of this speaker at 0.42m distance, coaxial with the tweeter. I am using my new Alpha Nirvana Class A amp, and an SMSL Sanskit 10 DAC for the output. Excitation was 1.64Vrms (0.33 watt). I took another measurement at exactly 0.5m and 2Vrms which indicates typical sensitivity for 2.83vrms at 1m just to have that data point for the record. Looks like this speaker box is a bit undersized and causes a large midbass hump which can be seen as a pressurization oscillation in the impulse/step function. A larger cabinet is needed for ideal operation. The pressurization causes higher distortion in the AC130F1 (a known problem) so ideally, a larger box will sound cleaner at lowe frequencies. Above 150Hz, this speaker shines relative to distortion. I am not sure why the Continuum, a well regarded speaker using a similar box size doesn't have any distortion complaints at lower frequencies? Also looks like the 2ohm padding resistor is uneccessary, although here a slight downward tilt can be pleasing. The 1kHz crossover integration though looks very smooth and I am pretty happy with that - it does sound quite good there. There is a definite aluminum breakup peak near 10kHz though. So not the smoothest driver at highs but has some characteristic aluminum cone "zing" to the sound.
Frequency Response (red is 1/8th cycle freq dependent window (FDW) and blue is unsmoothed):
Distortion:
Impulse and Step (UMIK has inverted response - large step should be positive):
Compare with Reference 2Vrms and 0.5m data (green) to show SPL sensitivity at usual 2.83Vrms and 1m standard:
So the takeaways are: larger box, reduce padding to maybe 1ohm or 0.51ohm resistor, maybe make as a TL for deeper bass with less distortion. But XO balance looks superb.
Manufacturer recommends 0.3 cu ft vented for 70Hz F3. For sealed, they recommend 0.13 ft cu which is very close to what I have.
Aurum Cantus AC-130F1 5-1/4" Woofer
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That 10khz peak is odd because it was not there on the previous units I had. If you look at the measured frequency response from post 1, it doesn’t have the huge 10kHz peak.
I think the driver has changed.
If I look at how much extended rubber from the surrounding touches the cone on the old ones, I think there is now less rubber and more aluminum.
Current ones:
Previous ones:
I still have them - the sure way to know is to swap them - but they are sort of hot glued into an open baffle speaker.
I think the driver has changed.
If I look at how much extended rubber from the surrounding touches the cone on the old ones, I think there is now less rubber and more aluminum.
Current ones:
Previous ones:
I still have them - the sure way to know is to swap them - but they are sort of hot glued into an open baffle speaker.
