My OB speaker

I was actually talking about beaming on the 8 incher, but if you can't spot it you're doing absolutely fine. It's there, but it's better if you don't try and find it.

If you don't have a box, you don't need the T/S, you need only an impedance vs frequency graph to work out a crossover. I remember seeing those on a fullrangers forum about 9 years ago, you'll have to start it off by Googling your model number and a few keywords, that's how I found some info (I don't remember where I saw it but I remember that I would hesitate to use that driver after seeing those measurements). It may have not been for the exact model, as Philips changed the speaker a bit over the years, but it'll be close enough.

Here's some interesting reading, to start you off, it's not the same driver as I once believed, but it'll give you some hints, and this was supposedly Philips' *best* fullranger:

Philips 9710/

Unfortunately the driver history of Philips is not very well documented or followed, so finding it can be hard. There's a catalog here, but it doesn't have anything apart from photos, but you might be able to see a few model numbers for further searching:

Philips A

hi cranky.,
thanks for those references. I read all the posts again. then i connected my speakers through crossover. the woofer is working better. without XO , i had to keep bass setting at 4 dB. with cross over, i had to tone it down to 0dB. so probably the woofer had beaming problem and probably was not working well as it was trying to produce higher freq. am i right? so probably i noticed the beamimg problem after it disappeared. But this made one thing sure. I am not going to miss bass on OB at least in music. I will have to try it in movies.

About T/S parameters, i think they were important for OB as well.

eg: Fs: building a box increases the resonating freq. but with OB , FS is not changed as there is no box. so probably a woofer with Fs 33 but in a box will have same resonating freq as compared to a woofer having Fs 45 put on OB.

MMs: Lower the Mms, better for OB as there will be no assistance from reflected waves.

xMax: no box , no protection. so it needs to have higher xmax.


of course i do agree that T/S parameters are not important for building a crossover
BTW, can you please explain me what is exactly meant by Q of a speaker? i know that there is mechanical and electrical and total Q . but what is Q?


Regards

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.

hello cranky. Thanks for that explanation. That clarifies a lot of doubts. Just wanted to clarify one thing. I am not using philips full ranger to drive lower freq. I am using a separate woofer for that purpose. With the cross over in the circuit, philips fr is working as midrange driver. If you see the pics in my album, the driver actually mounted on baffle is the woofer(locally made). The philips is on the top of the box without any baffle. i like the mids produced by it. One more question. How do you remove the whizzer cone?

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 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

As a cat plays with a mouse, perchance?

suri sir, me not understanding what are you saying pleez be clear....

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.

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.