Warminster, right inbetween Bath and Salisbury. So really you would have to get the train from Bristol to there, then a lift onwards. It was just a thought in case the destination is not near a train station.
Anybody really want to host this? I have my own place, which we could maybe possibly use if we are stuck, but let's see what else is on offer first 😉
Anybody really want to host this? I have my own place, which we could maybe possibly use if we are stuck, but let's see what else is on offer first 😉
I haven't thought of a location yet, that seemed a little premature!
But I do know of a couple of London Pubs with rooms we could borrow if need be,
But if wanted to make a night of it then we would need somewhere with cheap b+B in the area, and that definately counts London out...
BTW, Love the hasndles on top of your speakers Stee-b! 🙂
But I do know of a couple of London Pubs with rooms we could borrow if need be,
But if wanted to make a night of it then we would need somewhere with cheap b+B in the area, and that definately counts London out...
BTW, Love the hasndles on top of your speakers Stee-b! 🙂
Yay! My pair have arrived. I only ordered them yesterday! My tweeters are out of stock. 🙁
I cant wait to get some MDF (or chipboard
) and make some boxes. 😀
I cant wait to get some MDF (or chipboard
) and make some boxes. 😀
Re: Re: Re: !!!!!!
Morel MDT30 I think, the faceplate looks like the MDT20 but the diaphragm looks like the 30, we have a genuine pair of 30's in another pair of speakers for me to compare them too.
I never said it was the best music in the world 😀
It just makes a very good test track.
I think maybe the XLS 10's had something to do with the overall quality of these lil monsters providing lotsa bass, but the mids cetainly are very nice indeed. Morel helps with that too.
#Matttcattt said:
Morel MDT30 I think, the faceplate looks like the MDT20 but the diaphragm looks like the 30, we have a genuine pair of 30's in another pair of speakers for me to compare them too.
DRC said:
boyz to men ? 😱 😱 😱 😱
I'm sending mine back 😀 😀
dave
I never said it was the best music in the world 😀
It just makes a very good test track.
I think maybe the XLS 10's had something to do with the overall quality of these lil monsters providing lotsa bass, but the mids cetainly are very nice indeed. Morel helps with that too.
Cheers pinkmouse I could have turned the box upside down and used the desk as the bottom of the box. It just lost a lot of novelty factor tho' so the handles remained.
Thanks again for highlighting the drivers in the first instance!
regards Steve
Sreten,sreten said:
I'm planning on using 3 drivers but unsure how BSDC would be implemented. Do you mean that the xover should be around the BSD point between mid and bass cabs? Does this make it a 3.5 way?
I'm churning over ideas: perhaps make them active (inbuillt GC's) but I think the load will be to much perhaps. The drivers are 6 ohm nominal, so two of these in parallel are going to give many amplifiers a tough load I think. What would you suggest?
David,daatkins said:
I've measured two of the drivers so far (without run-in) and they both measured fs: ~93Hz, Vas: ~2l, and Qts: ~0.71. They're running in at the moment, but unless the fs drops some 30Hz etc., then I think the manufacturer specs are out by a bit.
Vikash said:
Myself and im sure most people will be very interested in your findings. I cannot wait. Thanks for doing it for me so I dont mess up with my box design. 😀
I seem to remember on the last lot of AP100s I had, the Fs settled down to about 70Hz, so a bit off spec, but not as much as Matt currently is seeing. I also remember quite a nasty resonance peak at around 4K as well that needed a little taming, and I always wondered if a retrofit phase plug might help.
Vikash
For the chip amp active solution, I will get around the impedance problems by using the triple LM4871, with one channel per driver.
It may not count as totally purist high end, with only one chip in each of the speakers driving both treble and bass, but it seems like a fun experiment to try!
Vikash
For the chip amp active solution, I will get around the impedance problems by using the triple LM4871, with one channel per driver.
It may not count as totally purist high end, with only one chip in each of the speakers driving both treble and bass, but it seems like a fun experiment to try!
Vikash said:
No it does not make it a 3.5 way as the mid unit is rolled off,
the bass units are 6dB more sensitive, so c/o gives BSC.
for a passive speaker :
******************
You are correct c/o point is arranged to implement full 6dB BSC.
Obviously c/o is first order or well damped second order.
For an active speaker :
******************
One amplifier per driver is no problem so use 4.
A single voltage rail design appeals for AC coupled mid and
treble, in this case use 2 bridged for the bass units in series.
You could arrange the bass units in push pull if so inclined.
When active you can reduce the bass units sensitivity and
c/o at any point you want to the mid and use active BSC.
Also when active note a 6dB/octave high pass can be
simply implemented by setting input coupling capacitors.
🙂 sreten.
Yay finally an excuse to put my lathe into service again 😀 I guess to do this you just cut off the dust cover and make a plug to fit in the middle with some clearance, and glue it in?
Steve
Basically, yes!
You might want to try different materials though, I always find the softer plastic ones sound better than metal, ( but metal does look much cooler!)
The dustcaps come off quite easily with a little warming and prying with a blunt scalpel blade.
You might want to try different materials though, I always find the softer plastic ones sound better than metal, ( but metal does look much cooler!)
The dustcaps come off quite easily with a little warming and prying with a blunt scalpel blade.
As a service to all the Maplin bargain hunters, and because I'm so great, I thought I'd post some measurements of my AP100Z0s.
First up is the T/S parameters measured using Speaker Workshop and the added mass method. These calculations are assuming a DC resistance of 5.7R, SD estimated to be 47cm^2 and the added mass was 11g (two 20p coins @ 5g each and 1g for Blu-Tak).
Speaker 1:
Fs = 92.6Hz
Vas = 1.78 litres
Qts = 0.57
Qes = 0.74
Qms = 2.58
Speaker 2:
Fs = 94.9Hz
Vas = 1.78 litres
Qts = 0.61
Qes = 0.78
Qms = 2.72
Something worth noting is that these are the exact same drivers that I measured 18 months ago and reported in this thread:
http://www.diyaudio.com/forums/showthread.php?threadid=9993
Something has clearly changed! The units are now fully run-in, but Fs is supposed to drop not increase. One possible explanation is that I could have used different power level for the two tests. To be honest, I'm not sure I'd trust any of these results...
Next up is free air impedance (unsmoothed) which shows Fs in the mid-90Hz reange. This is quite different from Pinkmouse's experience although very similar to Vikash:
First up is the T/S parameters measured using Speaker Workshop and the added mass method. These calculations are assuming a DC resistance of 5.7R, SD estimated to be 47cm^2 and the added mass was 11g (two 20p coins @ 5g each and 1g for Blu-Tak).
Speaker 1:
Fs = 92.6Hz
Vas = 1.78 litres
Qts = 0.57
Qes = 0.74
Qms = 2.58
Speaker 2:
Fs = 94.9Hz
Vas = 1.78 litres
Qts = 0.61
Qes = 0.78
Qms = 2.72
Something worth noting is that these are the exact same drivers that I measured 18 months ago and reported in this thread:
http://www.diyaudio.com/forums/showthread.php?threadid=9993
Something has clearly changed! The units are now fully run-in, but Fs is supposed to drop not increase. One possible explanation is that I could have used different power level for the two tests. To be honest, I'm not sure I'd trust any of these results...
Next up is free air impedance (unsmoothed) which shows Fs in the mid-90Hz reange. This is quite different from Pinkmouse's experience although very similar to Vikash:
Attachments
And finally the 1/3 octave smoothed frequency response measured in 3.5 litres sealed (a pic of the test box is on page two of this thread). The peaks around 5KHz proves Pinkmouse's memory isn't totally shot.
The difference in amplitude between the nearfield results could be due to not having the mic the exact same distance from the dust cap.
I hope this helps some of you.
Nice one,
David.
The difference in amplitude between the nearfield results could be due to not having the mic the exact same distance from the dust cap.
I hope this helps some of you.
Nice one,
David.
Attachments
😀daatkins said:
I used SD = 52cm2. I got this value looking at the other Audax 4" drivers with XX100XX model numers. Just for comparisson, I used 3.56g (blu-tac weighing same amount as 1p coin) for the added mass method. Looking at your weight, I'm not sure if I used enough...daatkins said:
My first measurements were with the drivers straight out of the packaging. I'm running them in now with a 15Hz signal, and hopefully they should measure much closer to published specs after a day or so (fs and qts should drop, vas should increase).daatkins said:
Is there a method to warming the area around the dust cap, or just put the driver next to the heater for a while?pinkmouse said:
A hair dryer will work if used carefully, (I used to use a hot air gun, but I had a lot of practise, and I don't recommend that method to anyone else! 
). Just treat them gently, work slowly, and you will be fine. 😉
). Just treat them gently, work slowly, and you will be fine. 😉Hello Vikash,
Good thinking! I estimated the SD by measuring the cone radius and adding 1/3 of the surround. Recalculating for my drivers using SD=52cm^2 gives...
Speaker 1:
Fs = 92.6Hz
Vas = 2.22 litres
Qts = 0.57
Qes = 0.74
Qms = 2.58
Speaker 2:
Fs = 94.9Hz
Vas = 2.28 litres
Qts = 0.61
Qes = 0.78
Qms = 2.72
Joe D'Appolito's “Testing Loudspeakers” book offers two rules when attempting the added mass method:
1 - add enough weight to shift the impedance peak by at least 25%
2 - add at least 60% more to the cone mass.
Audax quotes the moving mass as 4.65g so you're satisfying rule #2. How much impedance shift are you seeing?
I should also correct what I wrote in the post above: I used two 20p pieces at 5g each. The 5p coin weights 3.25g.
It'll be interesting to see the results after a day or two of running-in. Please be sure to post!
Nice one,
David.
Good thinking! I estimated the SD by measuring the cone radius and adding 1/3 of the surround. Recalculating for my drivers using SD=52cm^2 gives...
Speaker 1:
Fs = 92.6Hz
Vas = 2.22 litres
Qts = 0.57
Qes = 0.74
Qms = 2.58
Speaker 2:
Fs = 94.9Hz
Vas = 2.28 litres
Qts = 0.61
Qes = 0.78
Qms = 2.72
Joe D'Appolito's “Testing Loudspeakers” book offers two rules when attempting the added mass method:
1 - add enough weight to shift the impedance peak by at least 25%
2 - add at least 60% more to the cone mass.
Audax quotes the moving mass as 4.65g so you're satisfying rule #2. How much impedance shift are you seeing?
I should also correct what I wrote in the post above: I used two 20p pieces at 5g each. The 5p coin weights 3.25g.
It'll be interesting to see the results after a day or two of running-in. Please be sure to post!
Nice one,
David.
Why do the Audax response graph only go up to 10/15k? They are specified to 20/30k so why dont the graphs show the response to these frequencies?
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