Alfred, a little off topic but...
thanks for the great links. I've bookmarked them and will use both as a future reference!
The "test" page is especially useful. I tried both with some small (but good) desktop speakers, and some IE headphones to similar effect. Rather than use a usefull tone, and level, I tested for audibility. It worked well. Guess I didn't think my hearing was that bad, but it does follow the typical loudness curves.
Even though I can't hear above some given frequency, I do subscribe to Mati Otala's "ultra-wide bandwidth" concept, as per Harmon Kardan 30-ish years ago, and I believe there is a "sense" of impressions made by ultrasonic (to humans at least) sounds and overtones that can make up a great system. I don't mean added to the signal, but rather as part of the signal. Digital has somewhat reduced these effects I think, mainly because of the filtering most DACS use .
Having said all of this, some of my best listening experiences have been with speakers that may measure poorly, but sound great '
'
stew
thanks for the great links. I've bookmarked them and will use both as a future reference!
The "test" page is especially useful. I tried both with some small (but good) desktop speakers, and some IE headphones to similar effect. Rather than use a usefull tone, and level, I tested for audibility. It worked well. Guess I didn't think my hearing was that bad, but it does follow the typical loudness curves.
Even though I can't hear above some given frequency, I do subscribe to Mati Otala's "ultra-wide bandwidth" concept, as per Harmon Kardan 30-ish years ago, and I believe there is a "sense" of impressions made by ultrasonic (to humans at least) sounds and overtones that can make up a great system. I don't mean added to the signal, but rather as part of the signal. Digital has somewhat reduced these effects I think, mainly because of the filtering most DACS use .
Having said all of this, some of my best listening experiences have been with speakers that may measure poorly, but sound great '
'stew
Hmm old thread but oke, new live.
I need a speaker for a open baffle who is -3 db at 50 a 60 hz, I did discover that there is shure a need for a high qts (best around 1).
The bas will be done by a pipe from 15 to 60 hz 24 dB actave filter.
I do use a two way for baffle, so woofer tweeter
regards
I need a speaker for a open baffle who is -3 db at 50 a 60 hz, I did discover that there is shure a need for a high qts (best around 1).
The bas will be done by a pipe from 15 to 60 hz 24 dB actave filter.
I do use a two way for baffle, so woofer tweeter
regards
I did find the Eminence Alpha 15A driver, with a Qts of 1.26. A fifteen incher w 3.8mm of Xmax, 97Db.
Plugging the values into the winISD beta sim, it wants a sealed baffle of course. The practicality of the sim has a giant box, adding volume to the sealed box driving the Qts down....for the infinite box it eventually hits the 1.25. It has a +2.77 Db "hump" at 47 to 53 Hz, falling thru 'zero' Db at 35 Hz. -3.06Db at 29.73 Hz.
Might be worth taking a look at??
___________________________________________________Rick.........
Plugging the values into the winISD beta sim, it wants a sealed baffle of course. The practicality of the sim has a giant box, adding volume to the sealed box driving the Qts down....for the infinite box it eventually hits the 1.25. It has a +2.77 Db "hump" at 47 to 53 Hz, falling thru 'zero' Db at 35 Hz. -3.06Db at 29.73 Hz.
Might be worth taking a look at??
___________________________________________________Rick.........
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I meant 1.26, the lowest it could gokinda odd as I just put together my cheap....free 6 X 9s' OB....I couldn't get any T/S parameters, so I did it by the book. I got 1.06 Qts............HHmmmm? And a Fs of sixty hertz..but it is right at four ohms. It will be sucking all my 600mA worth of power. You'd be surprised.
I put 12 ohms worth going to an DVC sub OB baffle, I added a panel on the back of the PC desk.
I got the two freebie, a relative took pity on me. Pioneer TS something something. I took off the silly so-called "four-way"...it just had two of those ultra-tiny piezos...yah, four=way huh?
Took the 'midrange" to do full duty, dropper down the cap...let it take some lower stuff..it has that silly metal cone.
I certainly had something here...but no wood.....But I did have that three or so ply veneer..........?? Some stiffening structure....super warped...plus I have multiple EQs........60 Db at sixty Hz.? no problem
Looks silly as hell .8M by 1.0 meters...I have a twin sheet set draped over them.
_________________________________________________Rick............
I put 12 ohms worth going to an DVC sub OB baffle, I added a panel on the back of the PC desk.
I got the two freebie, a relative took pity on me. Pioneer TS something something. I took off the silly so-called "four-way"...it just had two of those ultra-tiny piezos...yah, four=way huh?
Took the 'midrange" to do full duty, dropper down the cap...let it take some lower stuff..it has that silly metal cone.
I certainly had something here...but no wood.....But I did have that three or so ply veneer..........?? Some stiffening structure....super warped...plus I have multiple EQs........60 Db at sixty Hz.? no problem
Looks silly as hell .8M by 1.0 meters...I have a twin sheet set draped over them.
_________________________________________________Rick............
My Ob (Pagliacci)
If any interested, one day i will write about them. Exciting, inexpensive, not too big, full passive XO, easy to drive, thought in every aspect and with a full range never seen here and very transparent. They are "I Pagliacci"
If any interested, one day i will write about them. Exciting, inexpensive, not too big, full passive XO, easy to drive, thought in every aspect and with a full range never seen here and very transparent. They are "I Pagliacci"
Attachments
Old drivers with high Q values were designed for OB designs (most were used in open back consoles). Both of my current speakers use vintage German speakers from the 1950's or earlier. They both run with aperiodic subwoofers on the baffle and helper tweeters rolled in with resistive padding and caps. The same speakers sound much worse with any back loading but sound absolutely wonderful open baffle - not vintage sounding at all.
Many of the modern speakers have good xmax but to low Q to work in the same applications and as a consequence cannot compete in OB designs with their vintage equivalents.
I would search the thrift shops to find some drivers to experiment with, I have had good success with even cheap vintage drivers, though often they need cone modification to give of their best. Avoid whizzers as they tend to produce a ragged top end and really don't work well to accurately replace a good tweeter rolled in above 10kHz.
Shoog
Many of the modern speakers have good xmax but to low Q to work in the same applications and as a consequence cannot compete in OB designs with their vintage equivalents.
I would search the thrift shops to find some drivers to experiment with, I have had good success with even cheap vintage drivers, though often they need cone modification to give of their best. Avoid whizzers as they tend to produce a ragged top end and really don't work well to accurately replace a good tweeter rolled in above 10kHz.
Shoog
My plan was a max 10 inch woofer and an folded baffle for space.
I do use a sub from 60 to lower in my case 15 Hz.
I have a long time seen that electuur has a subwoofer system who has one box on two channels with a special crossover filter but i can not find it anymore, I have now one sub on left channel, this is not a good idea because I now miss info from right bass, and with modern technologie of recording bass has to be also both channels, so maybe that crossover has of to be use, maybe visaton has some info about this type of filter.
I have record some samples, with a simple photo camera so it distords when there is bass or to loud, but maybe it give a idea, the amplifiers are hybrides tube mosfet, penthode input, dc coupled to fets.
DSCN1278 - YouTube
I do use a sub from 60 to lower in my case 15 Hz.
I have a long time seen that electuur has a subwoofer system who has one box on two channels with a special crossover filter but i can not find it anymore, I have now one sub on left channel, this is not a good idea because I now miss info from right bass, and with modern technologie of recording bass has to be also both channels, so maybe that crossover has of to be use, maybe visaton has some info about this type of filter.
I have record some samples, with a simple photo camera so it distords when there is bass or to loud, but maybe it give a idea, the amplifiers are hybrides tube mosfet, penthode input, dc coupled to fets.
DSCN1278 - YouTube
Attachments
43 cm wide 120cm tall, helper woofer loaded with an aperiodic box. This works well and keep the woofer (10 inch) and box to a manageable size.
Shoog
Thats still not going to address the baffle step fall off - just push it a little lower. Aperiodic loaded woofers allows box volumes of 1-2 cu ft and gives a similar response to TL loading. Softer than a TL though and slightly higher roll off.
I have seen the enormous 15" pairs of drivers on each baffle which is necessary to keep up with a decently sensitive fullrange - and decided it was not a sensible solution. Aperiodic is a good and flexible alternative which is fairly forgiving of woofer selection and achieves good SPL's with relatively small drivers.
Shoog
Just thinking out loud here.....
If you put two units in a box, one in front and one in the back....Then if phased correct it would still be a OB. Then if you made a phase shift filter (one the back unit) with a frequency equal to the lower frequency of the baffle, then it should start to phase shift and work like a closed box. I know it is a compromise but maybe you can use the idea.
If you put two units in a box, one in front and one in the back....Then if phased correct it would still be a OB. Then if you made a phase shift filter (one the back unit) with a frequency equal to the lower frequency of the baffle, then it should start to phase shift and work like a closed box. I know it is a compromise but maybe you can use the idea.
Sealed box woofers with an effective halving of the box size will require quite a specialized woofer to work well, and it will require a dedicated amp to keep up with high efficiency fullrangers. I think such a dipole has been successfully implemented though.
Shoog
Hello again
Thank you everybody for advice. My intention was to use Peerless 10' 8 Ohm, in sealed box of approx. 70 or so liters, attached to the lower part or half of an OB. OB should be 120cm tall and some 45cm wide. FR should be Visatone B 80, 6 Ohm placed at 90cm, maybe even lower-80cm? Cross freq. at 200Hz? Simple discrete Xover. Active or bi- amplification does not belong to 'hard core' or old school for my taste.
Alas, I don't know enough of the technicalias and calculation on this subject. So next post will have my questions if you don't mind?
Branko
Thank you everybody for advice. My intention was to use Peerless 10' 8 Ohm, in sealed box of approx. 70 or so liters, attached to the lower part or half of an OB. OB should be 120cm tall and some 45cm wide. FR should be Visatone B 80, 6 Ohm placed at 90cm, maybe even lower-80cm? Cross freq. at 200Hz? Simple discrete Xover. Active or bi- amplification does not belong to 'hard core' or old school for my taste.
Alas, I don't know enough of the technicalias and calculation on this subject. So next post will have my questions if you don't mind?
Branko
1. The front plate or OB. Thicker for better stiffness or not? Thinking between baltic plywood of 21 or 25mm, for the bottom of the woofer box too. Or to switch to MDF? Thckness...?
2. Calculation for the Xover? Should i take woofer under calculation for the 1st order and FR under 2nd order? Or both the same...? Which one?
3. Aperiodic speaker is the one with some sort of variovent?
2. Calculation for the Xover? Should i take woofer under calculation for the 1st order and FR under 2nd order? Or both the same...? Which one?
3. Aperiodic speaker is the one with some sort of variovent?
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Sealed box needs more power so my guess would be that some sort of biamping would be necessary for it to keep up with the FR. Ported is better - there are three types of ported with my estimation of their qualities;
- Transmission line : best bass with lowest extension depending on line length. Bigger boxes required.
- Aperiodic : next best bass with slightly less extension and a more gradual roll off. Requires relatively small box. Easy to design. (Yes it is the one with the stuffed vent which allows pressure release with minimal acoustic output from the vent).
- Bass reflex : worst bass, very abrupt cutoff and a boost of bass at the cutoff freuency. least natural sounding bass. Can be relatively small box enclosure.
I Believe that a 45cm baffle will give a cutoff at around 400hz not 200hz.
Shoog
- Transmission line : best bass with lowest extension depending on line length. Bigger boxes required.
- Aperiodic : next best bass with slightly less extension and a more gradual roll off. Requires relatively small box. Easy to design. (Yes it is the one with the stuffed vent which allows pressure release with minimal acoustic output from the vent).
- Bass reflex : worst bass, very abrupt cutoff and a boost of bass at the cutoff freuency. least natural sounding bass. Can be relatively small box enclosure.
I Believe that a 45cm baffle will give a cutoff at around 400hz not 200hz.
Shoog
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