My OB speaker

suri · #21 3rd July 2009, 09:11 PM

Quote:

Originally Posted by cranky

Beaming is not about bass, it's about uncontrolled dispersion. When you move around different parts of the room, you will hear gross issues in FR. Like I said, you may not even notice it that much...

What you were probably hearing was the typical Philips fullrange peaky sound signature, and once you cut the extra HF, you can hear it producing some bass. The bass was always there, just masked by the HF.

Actually, Fs is not a part of the T/S params, those are VAS, Qes, Qts, BL, mms etc. They help in designing a box for correct system compliance. The only thing needed for an OB is the Qts, so you know whether it will work in OB or not as low Q drivers do not work well there. Both Fs and xmax are quoted separately from T/S.

Most high-Q drivers, for OB use, have a very low xmax due to a stiff suspension required to set up the higher Q in the first place. Also, higher xmax drivers sound worse because of the length of the magnetic gap, with smaller xmax the designer can keep more of the coil in the gap so the driver is working in its linear range.

Mms has no correlation with reflections. It is a measure of the moving mass of a driver, including the air. It (in conjunction with BL) gives a measure of the total compliance of the driver. Or perhaps I'm not understanding where you're coming from?

Q is a measure of energy storage, very loosely speaking. It also is sometimes defined as the strength of resonance. A low Q driver or system will have a prominent and peaky resonance, lower Q drivers and systems will have gentler resonances. The principle is the same for all kinds of system Q - including those you may encounter in inductors, for example, not just speakers.

As a cat plays with a mouse, perchance?

jaudere · #22 4th July 2009, 01:23 AM

Quote:

Originally Posted by hitensitapara

Hi jaudere
Sorry for joing in late. But you have done a good job. Finishing and workmanship is superb. I hope material you are using for cabinet is particle board or soft board, so sound waves inside the cabinet doesn't bounce back or you can use layers of cotton inside the cabinet. Old Philips stereo wood speakers used to have them. (Ignore this comments if you have already thought of that)
Keep up the good work and pl. put pics of finished product.
Regards
Hiten

Thanks for the complements.I will convey them to my carpenter. Actually what you are seeing in the pics is my test baffle when i was planning to use full range driver. when i read a lot after designing that thing, i decided to go to 3 way open baffle speaker. i am waiting for the final baffles.(supposed to arrive tomorrow.)
as the system is open baffle, there won't be any cabinet. of course the bass part will have folded wings . so the reflected waves are likely to create problem. will be using 18mm plywood. so i will need some damping.i have not yet finalized the material which is to be used for damping.

people have used a lot of things including bath towel.i may use foam.

Cranky, can you please suggest damping material? is foam alright? how thick it should be? or anything simple and non toxic? i have 2 kids at home. so I will need something non toxic.

jaudere · #23 4th July 2009, 01:35 AM

Quote:

Originally Posted by cranky

A baffle on the mid (I know you're using the Philips as the mid

) will help increase the efficiency a bit, there is a smidgen of a backwave even on a mid.

The whizzer can be removed by using a hobby knife to cut out the extended portion, followed by a scraper for fine trimming. Be careful not to remove any of the voice coil material, the whizzer is glued to the voice coil itself. Two runs are advised, and a practice run on a cheap driver will help you stay out of trouble. There are a lot of cheap (<100) speakers you can practice on.

hi cranky,

i am helpless till i get the baffles. at present i am listening to music on that half H frame-half no baffle design, that too on only one side. the other side is having a full ranger again without any baffle. i am supposed to get the baffles tomorrow. but even with the single channel, the music is better than my regular speakers.

today i listened to "Tere bin jeena nahi" by bali bramhabhatta(anupama verma and Bikram Saluja in the video) and Oh sanam by lucky ali. what an experience. i hope it will further improve after i get both channels on proper baffles.

about removing the whizzer cone, i think i should not fiddle with it,especially when i don't know the cut off between mid and the tweeter. if the point is around 5Khz, the whizzer cone should not interfere. to get a new driver needs a lot of efforts at my place. i will have to travel 250km to Pune to get a new philips driver in case i don't like sound after removal of the cone.anyway i am liking the sound with the cone on.

jaudere · #24 5th July 2009, 02:55 AM

hi friends. My baffles arrived today. I put all the drivers on the baffle and connected them to amp through cross over. As soon as i played a song , my wife reflexly told me that the speakers are much better. We listened to 'tu hi re' from bombay. What an experience. I had never before noticed that there is a sound of group violin in the background which follows the lead vocals. Just beautiful. Of course the drivers are yet to break in. Damping is to be done. Will upgrade the cables tomorrow but at present i am quite happy with the product. Will post pics soon.

jaudere · #25 8th July 2009, 08:47 PM

hi friends,

here are some snaps finally.still in testing phase. working great in 4 way. was lacking a bit in bass in 3 way design. thanks a lot to all those who helped me understand speakers and of course to my carpenter who helped me convert the theory into practical.

height: 4 ft, width 20", depth 1 ft max, wt, i don't knw. driven by yamaha rxv 361 and a locally made amp for sub. all the speakers including the subs are on open baffle.
cost: Rs 5000 in total for drivers and XO, wood work: rs 2500. transport, may be around rs 1000.

1) 4way design: philips tweeter, philips octagonal as mid, philips round as mid bass and 15" as bass, driven by separate amp.

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2) 4 way speaker
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3) tweeter and mid from back, with the XO
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4) the speaker is divided in 2 parts. upper for mid and tweet, lower for mid bass and bass. fixed with 2 large screws. the lower part has wider baffle: 40" including wings.did so as it will be helpful for transport in case i change my residence.
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5) this was a 3 way design. the lower 2 were connected in series to get 8 ohm load. was not using sub amp in this setting. the philips round full range was working as mid here.

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6)working on upper part
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7) the mid bass and bass baffle
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regards

jaudere · #26 16th July 2009, 12:03 AM

Hi friends,

here is the picture of final AV set up. of course it is yet to get polished.for that i will have to wait till the monsoon gets over.

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I will call it as PIY (plan it yourself) rather than DIY.i planned everything but the major work was done by carpenter. nevertheless i am quite happy with the result.

of course everyone thinks that his project is very good. someone else should appreciate it. i am going to get that chance on that week end.one of my friends who is a music buff and into DIY since long will be visiting my place. will let you know his opinion. of course all of you are welcome. the problem is that i stay in a typical konkan village(the ones which are run by Gram panchayat) about 300km from Mumbai. so one has to plan a picnic of 2 -3 days in case there is a plan to visit my place.

jaudere

hitensitapara · #27 16th July 2009, 09:44 AM

Hi jaudere
After polishing whole setup will look good. I hope sound quality is good as only you can be the judge. Anyway there is always a chance and fun to improve as a DIYr

Lucky you living in Konkan Village, Konkan and Goa are beautiful places.

my regards
Hiten

grubyhalo · #28 16th July 2009, 11:52 AM

Looks pretty neat and im sure sounds that way too. Don't forget to 'polish' the baffle, it would look nicer still. BTW, sounds like you're living in an idyllic place!

jaudere · #29 16th July 2009, 01:35 PM

thanks grubyhalo. What is an idyllic place? I am living my dream. My dream was to get best possible education in india , use it for people in rural india & at the same time enjoy my life without missing much of fun. God has been very gracious to offer me all of that.

grubyhalo · #30 16th July 2009, 01:42 PM

Quote:

Originally Posted by jaudere

thanks grubyhalo. What is an idyllic place? I am living my dream. My dream was to get best possible education in india , use it for people in rural india & at the same time enjoy my life without missing much of fun. God has been very gracious to offer me all of that.

One definition of idyllic is simple and beautiful. Good to know you're living your dream, not a lot of people reach there.

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