I guess Qts should decrease with more usage of this drivers.Maybe they need longer period of running in.Haven't tried it though. Simulation with high Q doesn't show any bump in bass.Maybe it is becuse of placement in corner.How far from back wall are your speakers? How big is your room? Have you damped the box properly? Where is port placed?
move them more ahead to the centre of room.
Which amplifier are you using?
move them more ahead to the centre of room.
Which amplifier are you using?
3x4m room.
I placed the speakers in the corner approx half a meter, maybe more, away from the wall.
I think I used enough damping.
The amp is a piece of crap but it's probably not the cause of the problem, although I'll experiment with another amp.
I'll come back in a few days with the reports after some more experiments.
I placed the speakers in the corner approx half a meter, maybe more, away from the wall.
I think I used enough damping.
The amp is a piece of crap but it's probably not the cause of the problem, although I'll experiment with another amp.
I'll come back in a few days with the reports after some more experiments.
I have had good results in the past with Nokia drivers which were also sold under Intertechnik's Gradient brand. They had the same cone/VC units as Visatons now discontinued WS...(B)F series but different baskets and much stronger magnets. Price was comparable. Unfortunately they are hardly available anymore. Their Peerless-made Gradient successors (TPC series) look also good for the money.
A cheaper alternative to most Visaton stuff is Monacor's "Number One" brand. Some of their products are obviously made by the same manufacturer (LPG) as most of the classic medium quality Visatons.
For high-quality projects I love the latest Seas drivers (tweeters and midwoofers).
Take all of this with a grain of salt. My priority in hifi design is uncoloured and low-distortion sound at low to medium volume levels.
I believe that good alternative for visaton AL drivers ,could me Monacor SPH AL series.They are anyway cheaper,for example Al 130 from Visaton costs 85 euros,and Monacor's SPH 130 AL costs 55 euros. I haven't tried any of them but they seem to be of same quality. I think Visaton doesn't have more quality drivers than Monacor, but Visaton is more expensive. In this cheaper to medium priced drivers league I think Monacor offers better price/quality ratio.I'm unsure of the highest end in their catalogue, since i haven't tried these drivers.
I also noticed these Gradient drivers which look almost alike Peerless someone mentioned before.
Doeas anybody actually know which company really manufactures their own drivers? I'm pretty sure that Monacor,Gradient and Visaton sell some of the chinese OEM stuff.I think most of the medium priced stuff from other manufacturers are being made somewhere on far east.
I also noticed these Gradient drivers which look almost alike Peerless someone mentioned before.
Doeas anybody actually know which company really manufactures their own drivers? I'm pretty sure that Monacor,Gradient and Visaton sell some of the chinese OEM stuff.I think most of the medium priced stuff from other manufacturers are being made somewhere on far east.
I think that this happens with a lot of speaker manufacturers. They use the brand name to promote medium to low-quality drivers at a price that's cheap with regard to high-quality ones, but big with regard to the quality you actually get, so people that can't afford expensive stuff will buy their products hoping that the quality is guaranteed by the brand name. But that's bussiness, I'd probably do it to if I had a speaker manufacturing company...Tomac said:
But back to the topic, I have Monacor in mind for a while. I'll probably stick with the Visaton tweeters (G20SC) and upgrade to a Monacor mid-woofer.
One more question about breaking in. After searching a bit on the forum I thought about putting the drivers face-to-face and use white noise filered down to 50Hz, with the drivers running in phase. Do you think that this way of breaking-in is effective? After how long do the drivers reach the stable "parameters"? And, how big the cone excursion has to be when breaking in?
Break-in
There must be almost as many ways of break-in as there are speaker builders. Pink noise, LF sweeps, 20-30 Hz sinus, trip-hop music, almost everthing you feel comfortable with works somehow. White noise must be one of the most unpleasant methods.
Put the drivers in their test box face-to-face and connect them with opposite polarity. I give them an unfiltered 24 h pink noise treatment because I have it on CD and I am lazy. I set the volume slightly above the drivers' linear excursion rating. Drivers with low power rating get special treatment, of course. And throw some thick blankets over the boxes during break in!
There must be almost as many ways of break-in as there are speaker builders. Pink noise, LF sweeps, 20-30 Hz sinus, trip-hop music, almost everthing you feel comfortable with works somehow. White noise must be one of the most unpleasant methods.
Put the drivers in their test box face-to-face and connect them with opposite polarity. I give them an unfiltered 24 h pink noise treatment because I have it on CD and I am lazy. I set the volume slightly above the drivers' linear excursion rating. Drivers with low power rating get special treatment, of course. And throw some thick blankets over the boxes during break in!
Here's exactly what I did. I fastened the drivers face to face with screws, approx 2 cm's away. I generated some white noise in CoolEdit, and FFT filtered it down to 50 Hz. I normalized the result and let it play in Winamp with repeat on. I've set the amp's volume so that the excursion was about plus/minus 4-5 mm's (the limit of distortion being 4.25 mm if I compute it (height of VC - thickness of front plate)/2 - overhung VC). The result was that almost no sound was getting to my ears except a slight earthquake-like rumbling. The cat didn't seem too pleased about it though, eventually it would become nervous (low CAF - Cat Acceptance Factor). I have put them in a big cardboard box in order to minimize the noise and I've let the PC run overnight. I haven't had the chance to re-measure them this morning to see the variations, but I'll do it this evening before resuming the process. I'll probably let them run for another 12 hours, if you say that the manufacturers measure the params after 24 hours of break-in.
Low CAF - good one! 
I don't have cats myself but my neighbour - and they seem to get highly disturbed by MLS noise, too.
Don't really know how manufacturers (mis-)treat their speakers before measuring... it would surely be nice to have an overview. I would guess that parameter variations are decreasing exponentially with break-in time. Hence I doubt that there will be _much_ difference between 12 and 24 hours.
Does somebody know better?
I don't have cats myself but my neighbour - and they seem to get highly disturbed by MLS noise, too.
Don't really know how manufacturers (mis-)treat their speakers before measuring... it would surely be nice to have an overview. I would guess that parameter variations are decreasing exponentially with break-in time. Hence I doubt that there will be _much_ difference between 12 and 24 hours.
Does somebody know better?
They can hear subsonic and almost subsonic frequencies I thinkHertzschmerz said:
Visaton has a thread with the description of the measurement procedure. Here it is http://www.visaton.de/vb/showthread.php?s=&threadid=5136
Also there is a description on the DST site I think, but I can't find it now.
Edit: I found the measuremet procedure description for DST http://www.d-s-t.com/generelt/measure.htm
They don't say anything about breaking in but we can ask.
From http://www.d-s-t.com/generelt/measure.htm :
At least they are honest.
So much about the accuracy of certain manufacturer specs...
At least they are honest.
So much about the accuracy of certain manufacturer specs...
Oh, I didn't see that. It's like saying "the car we sell you has 4, maybe 8 cilinders, you'll have to buy it to see exactly".
Another question about break-in. This is a basic thing but I haven't given it much thought until now, because measuring drivers wasn't any of my concerns. So, the question: is the Xmech the maximum total cone excursion, or the distance from equilibrium position to the minimum/maximum position? More precisely, is it the peak-to-peak excursion or the amplitude of the excursion?
One more thing: what exactly happens if this rating is exceeded? Does the VC touch the rear pole plate, or does the spider break?
Another question about break-in. This is a basic thing but I haven't given it much thought until now, because measuring drivers wasn't any of my concerns. So, the question: is the Xmech the maximum total cone excursion, or the distance from equilibrium position to the minimum/maximum position? More precisely, is it the peak-to-peak excursion or the amplitude of the excursion?
One more thing: what exactly happens if this rating is exceeded? Does the VC touch the rear pole plate, or does the spider break?
Looking for posts about the AL130, I stumbled across this thread/post.Tomac said:
If you look closer at the AL130 vs SPH 130AL, you will see that the AL130 has a number of features the SPH130AL lacks. To mention three of them:
- The AL130 shows no signs of severe cone break up below 8kHz.
- The AL130 possesses an impedance shortening ring, making the impedance much more linear and reducing severely the distortion at midrange frequencies.
- The AL130 basket is more open to allow the backwave to flow freely and obtain an open, less compressed sound.
With regard to distortion (both linear and non-linear), you're talking here about quality that only way more expensive drivers such as the Accuton C2 88/6 can deliver.
Hi,
for any beginner reading this thread, Qts is important in choosing the method of loading the bass.
Low Qts suits horn and reflex (ported).
Mid Qts suits sealed box.
High Qts suits infinite/open baffle.
Qts=0.4 is near the upper limit for reflex loading.
Qts=0.5 is well into sealed box loading.
Qbox of >1.0 is the upper limit to avoid boominess.
Qbox >0.9 will sound boomy in a smaller room or closer to boundaries.
Finally, adding series resistance, from cables, crossovers and/or amplifier output impedance, will raise the Qts and Qbox.
for any beginner reading this thread, Qts is important in choosing the method of loading the bass.
Low Qts suits horn and reflex (ported).
Mid Qts suits sealed box.
High Qts suits infinite/open baffle.
Qts=0.4 is near the upper limit for reflex loading.
Qts=0.5 is well into sealed box loading.
Qbox of >1.0 is the upper limit to avoid boominess.
Qbox >0.9 will sound boomy in a smaller room or closer to boundaries.
Finally, adding series resistance, from cables, crossovers and/or amplifier output impedance, will raise the Qts and Qbox.
AndrewT said:
Barring rules of thumb about the Qts, I think one big thing to consider is the setting in which the speakers will be used. After hearing lots of ported systems, I've come to believe that ported systems are just not suited for indoor usage, unless your listening room is practically a cathedral. The flat anechoic response might look good on paper, but multiplied by the room gain it tends to produce unnatural "thump" effects in the bass.
And apart from that, a low Q implies a relatively high motor BL and inductance, which is also important for preventing internal box resonances from affecting the movement of the cone and colouring the output at midrange frequencies.
For that reason, personally, I usually prefer to use low Q drivers in sealed boxes, despite the reduced bass extension.
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