Vivek said:
I would not worry too much about that.
1. in a 2.5 way the impedance drops to 4ohms or even 3 ohms over only a small freq. range. In this case it would be from 80-400Hz.
2. what denon reciever do you have? does it have connections for 2 pairs of speakers? I find it hard to believe that in this day and age you get amps that cant handle impedances below 6 ohms. the original watt (wilson audio tiny tot) impedance fell to 1.5 ohms. I have run 2 pairs of 4 ohm (nominal impedance) speakers using an old Harmon Kardon PM665 integrated amp in 1987 for few hours without a problem.
Mine is the AVR 1403. 60W per channel @ 8 ohm impedance. And yes, it has connections for two pairs of speakers. The label on the back says 6 to 16 ohm if only speaker A is connected and 12 to 16 ohm when both pairs A and B are connected. What say thou?
Vivek
Vivek
me thinks the 1403 will do ok if not stressed. i looked at this and noticed that it might run low impedance loads if they are mostly resistive. hope you are using a zobel on the woofers. that will help.
while a 2.5 way TC18 would prefer a beefier amp like the 1803 the 1403 will be fine if you dont demand more than say 10-15W continous from it.
given that you do get a 3db sens gain from a 2.5 way i'd say that is a fair tradeoff.
10W rms might not sould like much but at 1m that would mean you'd be doing 98db and about 92db at 2m. not too shabby. add room reinforcement and for a mid sized indian apt. (200 sq. ft. 9ft ceiling) this should do fine for all but party applications.
one reviewer stated that he has used the 1403 with the MMG (maggie). the maggie is a low impedance speaker but the load is quite resistive. resistive loads dont stress an amp as much as a reacitve load.
while a 2.5 way TC18 would prefer a beefier amp like the 1803 the 1403 will be fine if you dont demand more than say 10-15W continous from it.
given that you do get a 3db sens gain from a 2.5 way i'd say that is a fair tradeoff.
10W rms might not sould like much but at 1m that would mean you'd be doing 98db and about 92db at 2m. not too shabby. add room reinforcement and for a mid sized indian apt. (200 sq. ft. 9ft ceiling) this should do fine for all but party applications.
one reviewer stated that he has used the 1403 with the MMG (maggie). the maggie is a low impedance speaker but the load is quite resistive. resistive loads dont stress an amp as much as a reacitve load.
I do not have zobels right now but intend to put them in.
My receiver has volume control from minus 60 to plus 18. I usually listen to music at -35 or -30 if I want it a little louder. Maybe I should try a 2.5 way. I might just go out and buy a couple more TC18s.
The Vifa dealer here also seems to think there should be no problem. He says he uses his MTM designs (with two 8 ohm woofers in parallel) with his Denon receiver and there is no problem. He has a speaker company called Acoustic Portrait and he says the measured impedance hovers around 6 ohm. He feels there will not be a problem.
Vivek
My receiver has volume control from minus 60 to plus 18. I usually listen to music at -35 or -30 if I want it a little louder. Maybe I should try a 2.5 way. I might just go out and buy a couple more TC18s.
The Vifa dealer here also seems to think there should be no problem. He says he uses his MTM designs (with two 8 ohm woofers in parallel) with his Denon receiver and there is no problem. He has a speaker company called Acoustic Portrait and he says the measured impedance hovers around 6 ohm. He feels there will not be a problem.
Vivek
Is Vivek referring to Mr.Shiva of Corrson, opposite Sagar Apollo Hospital, 15th Cross, Jayanagar 4th T Block, Bangalore?
Re: TS parameters of Peerless India drivers as supplied by the distributor.
Dev has Dainty too. But could not find the specs yesterday.
The 8" Peerles is Rs. 950 & the 10" is Rs. 1800.
And he rather sell a pair. Was making abit of a fuss selling a single.
Is it worth paying double for them?
rakeshln said:
Dev has Dainty too. But could not find the specs yesterday.
The 8" Peerles is Rs. 950 & the 10" is Rs. 1800.
And he rather sell a pair. Was making abit of a fuss selling a single.
Is it worth paying double for them?
Vivek said:
yes that is it. the 90 deg phase shift of the 1st order LP XO for the second woofer is compensated by the rear placement.
dave planet 10 has a longer explanation on his website
KSPV,
I am referring to Shiva of Corrson.
Navin,
Got it. Let me do some more reading on the subject. I will let you know what happens.
Thanks,
Vivek
I am referring to Shiva of Corrson.
Navin,
Got it. Let me do some more reading on the subject. I will let you know what happens.
Thanks,
Vivek
Vivek, we've been in touch off-line, and I've let you know whatever I think about your speaker project. As you've seen, I've never recommended push-push for your case, though Navin, Dave and others keep talking about it. The best piece I've read on the push-push approach is the subwoofer design that Lynn Olson has suggested for use with the ME2. I wanted to give you a URL to that write-up, but it's no longer there in the original site, and I couldn't find a new location for the page. (Help me, anyone?)Vivek said:
The reason why I don't recommend a push-push for a two-way is because one driver will face backwards at fairly high frequencies. If your push-push pair rolls off at 100Hz like most subs, it's great. (That's the kind of application Lynn Olson described, for instance. His ME2s give an F3 of about 70Hz, and his Ariels about 55Hz, IIRC. So he can afford to let his sub cut off at 100Hz or even lower.)
At frequencies above about 150Hz, drivers are clearly very directional and a rearward facing driver will give you its output bounced from the rear wall. This will almost certainly muddy the midrange and the soundstaging, IMHO. But I've never made a push-push of this kind and actually listened to it, so I may be wrong. All I can say is that given my current level of knowledge, I'd never try to make a two-way with push-push midbass drivers. Push-push subs (true subwoofers, not just woofers, mind you) are a different issue altogether.
tcpip said:
pls read...
http://www.t-linespeakers.org/tech/bafflestep/intro-bds.html
1. the rear woofer will roll of at about 300Hz 6db. Yes there will be considerable output above 150Hz and even as high as 600Hz. if the speaker is kept less than 3 ft from the rar wall tis will muddy the midrange if you can afford to bring the speaker out 3ft or more then the delay will add space to the sound.
2. there is research to show the some reflectins make matters worse with others help. very early reflections usually muddy the sound, very late relfections make the sound wierd like it has an echo.
i respect lynn and dave. dave has used / recomended dipole for fullranges like the FE103 and JX92.
in addition to this I have some experience with the roll off from firing a woofer rear wards. one way fo you to quickly find out. is to disconnect your tweeter and turn your cabinet 180 deg. you will then hear the woofer somewhat. dipoles are more room dependant that monopoles. ever tried setting speakerslike Maggies up? AAARGH!
http://homepage.mac.com/tlinespeakers/TLS/FALL/images/Hugos-TL-pipes.jpg
nice pic of what you can try.
nice pic of what you can try.
Re: High Q drivers.
Ashok,
I have played around with the Boltons a bit, and tried some of their drivers. I think, for those starting DIY and building their first box, Bolton can be good drivers to experiment. They are quite affordable and can tolerate abuse.
Bolton makes a dome tweeter which looks good but SPL curves vary from driver to driver and I do not use them any more, I rather like the Philips dome, with the Boltons they do not sound too bad.
I have not experimented with any 10/12 inch Bolton woofers yet, but I briefly measured the Fs and Q for these following drivers.
25IMW21 Fs=30.4, Qms=4.9, Qes 0.66 Qts 0.58
30IMW22 Fs=29.4, Qms=6.05, Qes0.763, Qts 0.68
I have not taken the Vas readings yet. The above readings were taken in the Bolton factory one evening, so I did not have a test box to measure the Vas. To measure Vas I would have to buy the drivers.
Bolton does not publish any TS parameters.
So far I have been able to specify my coil length and magnet size, so I could get one off custom made drivers. Mr. Monga the owner is a nice man and encourages DIYer to experiment with his drivers. You can write to him directly and order your drivers, they will be much cheaper than your local dealers.
I have seen many drivers in Chadni Chowk, but have not purchased any yet. They are not that cheap either.
I had measured one Dainty 8 incher SW801
Fs=54.9,Qms=3.92, Qes=1.57, Qts=1.12 Vas 18.9L
Angshu
ashok said:
Ashok,
I have played around with the Boltons a bit, and tried some of their drivers. I think, for those starting DIY and building their first box, Bolton can be good drivers to experiment. They are quite affordable and can tolerate abuse.
Bolton makes a dome tweeter which looks good but SPL curves vary from driver to driver and I do not use them any more, I rather like the Philips dome, with the Boltons they do not sound too bad.
I have not experimented with any 10/12 inch Bolton woofers yet, but I briefly measured the Fs and Q for these following drivers.
25IMW21 Fs=30.4, Qms=4.9, Qes 0.66 Qts 0.58
30IMW22 Fs=29.4, Qms=6.05, Qes0.763, Qts 0.68
I have not taken the Vas readings yet. The above readings were taken in the Bolton factory one evening, so I did not have a test box to measure the Vas. To measure Vas I would have to buy the drivers.
Bolton does not publish any TS parameters.
So far I have been able to specify my coil length and magnet size, so I could get one off custom made drivers. Mr. Monga the owner is a nice man and encourages DIYer to experiment with his drivers. You can write to him directly and order your drivers, they will be much cheaper than your local dealers.
I have seen many drivers in Chadni Chowk, but have not purchased any yet. They are not that cheap either.
I had measured one Dainty 8 incher SW801
Fs=54.9,Qms=3.92, Qes=1.57, Qts=1.12 Vas 18.9L
Angshu
Large drivers.
Hi Angshu,
Thanks for the interesting info on the Bolton drivers. You are right , I better contact Mr. Monga and see what I can get.
The Chandni Chowk drivers were expensive .
I wonder how long the Bolton drivers last . I mean the glues , the spiders and the surrounds. I guess all of it is imported !
Thanks,
Ashok.
Hi Angshu,
Thanks for the interesting info on the Bolton drivers. You are right , I better contact Mr. Monga and see what I can get.
The Chandni Chowk drivers were expensive .
I wonder how long the Bolton drivers last . I mean the glues , the spiders and the surrounds. I guess all of it is imported !
Thanks,
Ashok.
i would like to know what the OD of the Bolton 8" is. By this i mean the frame/basket OD. anyone?
Re: Large drivers.
Ashok,
I am using Bolton 16SJW22 for more than 5 years, beat them up real hard, still playing fine. Never had any problems with their drivers, except for dome tweeters. Once I had a minor mechanical problem and Monga replaced it promptly. He uses imported cones.
You can reach Bolton at:
Bolton Private Ltd
14/3 Milestone
Mathura Road
Faridabad 121 003 Haryana
Tel 0129 227 5410, 0129 227 5332
You can call the second number and speak to Rajbeer for prices. You can take my reference.
Mr Monga does not have email, all written communication is by normal mail. So it can take a while to get a response. In case you face any difficulties then let me know.
I am attaching a page from his old catalog, some of these drivers may be still available, please call Rajveer and confirm availability.
Angshu
ashok said:
Ashok,
I am using Bolton 16SJW22 for more than 5 years, beat them up real hard, still playing fine. Never had any problems with their drivers, except for dome tweeters. Once I had a minor mechanical problem and Monga replaced it promptly. He uses imported cones.
You can reach Bolton at:
Bolton Private Ltd
14/3 Milestone
Mathura Road
Faridabad 121 003 Haryana
Tel 0129 227 5410, 0129 227 5332
You can call the second number and speak to Rajbeer for prices. You can take my reference.
Mr Monga does not have email, all written communication is by normal mail. So it can take a while to get a response. In case you face any difficulties then let me know.
I am attaching a page from his old catalog, some of these drivers may be still available, please call Rajveer and confirm availability.
Angshu
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