Hi guys, I need your precious support!
I've a pair of Isophon P 203 S alnico speakers; they were fitted on a pair of Telefunken TL-80.
Just for precision, I've to specify these speakers are also known as Isophon PSL 203 S.
First of all, dear friends, do you think they're decent speakers?
That said, I'd like to build a pair of 2 way bookshelf loudspeakers with these vintage speakers.
Size of each cabinet: 25 liters max. (unfortunately, the space is small).
The type of the system it's not important to me: bass reflex, infinite baffle, closed box...or open baffle (I mean: a classic and common speaker chassis but with no back cover).
If it's possible, I prefer do not use complex cross-over (I don't want to reduce the woofer S.P.L.).
Well, I've no idea about the tweeters to use in this project.
I already own two pair of tweeters...but if you repute them as not suitable, please, guys, could you recommend me some tweeter right for this project?
The tweeters I already own are:
1) a pair of Philips AD0160/T4
here're the specs:
http://www.troelsgravesen.dk/WWDT_files/ad0160.pdf
2) a pair of Peerless alnico MT 25 HFC (I hope don't mistake them with the MT 225 HFC, but if you want I can post a picture).
Please guys, could you help me? without your support, I can't do anything
Thank you very much in advance for your kindness and your patience!
Regards!
I've a pair of Isophon P 203 S alnico speakers; they were fitted on a pair of Telefunken TL-80.
Just for precision, I've to specify these speakers are also known as Isophon PSL 203 S.
First of all, dear friends, do you think they're decent speakers?
That said, I'd like to build a pair of 2 way bookshelf loudspeakers with these vintage speakers.
Size of each cabinet: 25 liters max. (unfortunately, the space is small).
The type of the system it's not important to me: bass reflex, infinite baffle, closed box...or open baffle (I mean: a classic and common speaker chassis but with no back cover).
If it's possible, I prefer do not use complex cross-over (I don't want to reduce the woofer S.P.L.).
Well, I've no idea about the tweeters to use in this project.
I already own two pair of tweeters...but if you repute them as not suitable, please, guys, could you recommend me some tweeter right for this project?
The tweeters I already own are:
1) a pair of Philips AD0160/T4
here're the specs:
http://www.troelsgravesen.dk/WWDT_files/ad0160.pdf
2) a pair of Peerless alnico MT 25 HFC (I hope don't mistake them with the MT 225 HFC, but if you want I can post a picture).
Please guys, could you help me? without your support, I can't do anything
Thank you very much in advance for your kindness and your patience!
Regards!
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Oh noooo!!! I'm sorry, guys...I forgot to ask a question!
I already know it's a stupid newbie question, so please, forgive my ignorance!
here's my stupid question/curiosity:
I know that the S.P.L. of the Isophon PSL 203 S is 88 dB/W/m.
Well, that said, if we add a tweeter into the cabinet with this speaker, does the S.P.L. of the loudspeaker (I mean:the general S.P.L) increase a little bit?
Thank you again for the patience!
Regards!
I already know it's a stupid newbie question, so please, forgive my ignorance!
here's my stupid question/curiosity:
I know that the S.P.L. of the Isophon PSL 203 S is 88 dB/W/m.
Well, that said, if we add a tweeter into the cabinet with this speaker, does the S.P.L. of the loudspeaker (I mean:the general S.P.L) increase a little bit?
Thank you again for the patience!
Regards!
Without measuring the drivers, it's all guesswork... so here's my guess:
Put the woofers in the biggest closed box you can; use a simple single cap crossover with the Peerless tweeters to cross over at ~ 4KHz (I have a pair of the Philips, & they're notoriously inconsistent). If that works, then move on to upgrading the xover to a single inductor on the woofer, & 2nd order on the tweeter. To get it accurate, you'll need impedance plots.
& no, adding a tweeter does not increase overall sensitivity.
Put the woofers in the biggest closed box you can; use a simple single cap crossover with the Peerless tweeters to cross over at ~ 4KHz (I have a pair of the Philips, & they're notoriously inconsistent). If that works, then move on to upgrading the xover to a single inductor on the woofer, & 2nd order on the tweeter. To get it accurate, you'll need impedance plots.
& no, adding a tweeter does not increase overall sensitivity.
Hi guys!
First of all, I want to thank you for the replies!
Said that, I found some information more about this speaker, I hope so much you can help me with these specs (just a clarification, guys,: VAS parameter is not correct, infact the correct one is 20/30 ltr.)
Isophon PSL 203/35 | Hifi-Wiki.de
Please, guys, help me!
Thank you so much!
Regards
First of all, I want to thank you for the replies!
Said that, I found some information more about this speaker, I hope so much you can help me with these specs (just a clarification, guys,: VAS parameter is not correct, infact the correct one is 20/30 ltr.)
Isophon PSL 203/35 | Hifi-Wiki.de
Please, guys, help me!
Thank you so much!
Regards
First lay the woofer on a fine mesh, which thou then pull up and tape,bind,glue together on the back of the magnet, so nothing can press gainst the piston and rattle round there. Then equip a 25 liters box with a bassreflex duct of 70mm diameter and 10cm length, and stuff everything with wool, especially the duct, so thou get mechanical damping and tenor efficiency gain. Then open a new page, partly covered by ink, partly blank yet, headlined by cross-over.
If the correct value of Vas is 30 liters, than Thiele-Small parameters favour 25 liters closed box.
Without measurements it is very hard to design a good crossover, but try this:
http://www.diyaudio.com/forums/mult...designing-crossovers-without-measurement.html
Edit: use Philips tweeter.
Without measurements it is very hard to design a good crossover, but try this:
http://www.diyaudio.com/forums/mult...designing-crossovers-without-measurement.html
Edit: use Philips tweeter.
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Why sad? These are good parts, the tweeters, too. Equivalent Volume is prolly at least 50 liters, and a 70 liters box provided very deep bass, but if space is short, we need to use a smaller box equipped with mechanical damping via the stuffed bass-reflex duct. Mechanical damping is not in any way flawed, in fact most of the good HiFi stuff from the fifties and sixties, before dome tweeters and bass-reflex were invented, was done with mechanical damping.
Thank you so much, dear Grasso789, for your precious encouragement and support!
You're very kindness!
Please, be patience with me...I don't speak english so well, so there's some thing I can't understand perfectly: for example, could you explane me (if that doesn't annoy you, of course) what is the mechanical damping?
Thank you very much for your collaboration
Regards!
Hi Sonce, first of all, thank you for your reply!
I can assure you, the correct Vas value is 20/30 Liters.
That is clearly specified in each isophon manual from 1968 until 1980.
Best regards!
The volumes specified in the Isophon Catalogs were not Vas but recommended enclosure volumes. Isophon did not publish Thiele/Small parameters till the 80s. I had a PSL 245/35 in the early 70s and the recommended Volumes were 40-60 Liters. These were highly compliant drivers designed for air suspension which was the standard at the time. The PSL 245 had a resonance in a 40 liter box of 64 Hz with a Qt (in the box) around 1.0
What a very strange thread!
Some old Isophon P203 woofer. Maybe this:
I can do the sums. Vas and Qts gives you the critically damped Qtc=0.707 box size. I make it twice the Vas here. Well you're not going to do THAT. People seemed to use about 50L back in the day. Maybe with a few holes drilled as a sort of aperiodic. Notice the single cap to a 4" sealed-back cone tweeter in the Norelco. The bass might have a coil, not sure.
25L would give you a box Qtc around 1.0. The Heybrook HB1 with a Vas of 81L and Qts 0.7 driver was like that. Made for a slightly lumpy bass.
I'd be surprised if this driver still works, TBH.
Some old Isophon P203 woofer. Maybe this:
I can do the sums. Vas and Qts gives you the critically damped Qtc=0.707 box size. I make it twice the Vas here. Well you're not going to do THAT. People seemed to use about 50L back in the day. Maybe with a few holes drilled as a sort of aperiodic. Notice the single cap to a 4" sealed-back cone tweeter in the Norelco. The bass might have a coil, not sure.
25L would give you a box Qtc around 1.0. The Heybrook HB1 with a Vas of 81L and Qts 0.7 driver was like that. Made for a slightly lumpy bass.
I'd be surprised if this driver still works, TBH.
Attachments
Seems to confirm the 3.8 DCR, Dave.
I wonder if AlNiCo magnets are all that special?
That Norelco is not disimilar to stuff I grew up with on a Valve Radiogram. Sounded very good.
I've always put the good sound down to lively cones and those old cone tweeters. Crossovers were rubbish by modern standards.
My workplace has a lot of old interesting junk in the basement. A complete Steepletone HiFi from about 1972. With Garrard SP25 turntable. Some very retro 7" ELAC ceiling line speakers with cloth surrounds and small voicecoils. Bit like SABA Greencones really, and they are a bit of a legend.
I've been tempted to have a go at the ELACs.
Amazing what people used to do back in the day.
I wonder if AlNiCo magnets are all that special?
That Norelco is not disimilar to stuff I grew up with on a Valve Radiogram. Sounded very good.
I've always put the good sound down to lively cones and those old cone tweeters. Crossovers were rubbish by modern standards.
My workplace has a lot of old interesting junk in the basement. A complete Steepletone HiFi from about 1972. With Garrard SP25 turntable. Some very retro 7" ELAC ceiling line speakers with cloth surrounds and small voicecoils. Bit like SABA Greencones really, and they are a bit of a legend.
I've been tempted to have a go at the ELACs.
Amazing what people used to do back in the day.
Attachments
Seems to confirm the 3.8 DCR, Dave.
I wonder if AlNiCo magnets are all that special?
That Norelco is not disimilar to stuff I grew up with on a Valve Radiogram. Sounded very good.
I've always put the good sound down to lively cones and those old cone tweeters. Crossovers were rubbish by modern standards.
My workplace has a lot of old interesting junk in the basement. A complete Steepletone HiFi from about 1972. With Garrard SP25 turntable. Some very retro 7" ELAC ceiling line speakers with cloth surrounds and small voicecoils. Bit like SABA Greencones really, and they are a bit of a legend.
I've been tempted to have a go at the ELACs.
Amazing what people used to do back in the day.
I loved my PSL203 in a DIY 15l shelfbox. That was in the early 70ies. The foam surrounding passed away in the 90ies, so I wonder whether any of these are still working.
That's not uncommon. Any foam surrounding may pass after some decades, due to inevitable degeneration of it's PU material. Fortunately, we can repair these issues rather easily in speakers with nowadays' common diameters.
Best regards!
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