Multimedia Satellites, Open Baffle?, Full Range? Driver Selection Help Required

[Timn8ter]

My figures aren't with me right now, but I think it would be about 4x5.5" internal. I'll have to dig up my worksheet later.

[zobsky]

Originally posted by joensd
Hi,
do a search here in the forums for the Tangband W3-781S fullrange driver. As you plan in a sub anyway they might be the perfect companion.
I´ve got some for my PC setup and they´re perfect for nearfield listening but don´t have enough low end.
You might wanna use two per side to get more output from them.
Or cross them over at >200Hz.

I wouldn't cross over at > 200Hz

I have this issue with my monsoon planar 14 PC speakers where the sub crosses over to the planar sats at around 200Hz.

The problem is that a 200Hz note is directional ie. you can locate where the sub is, ... I managed to overcome this issue somewhat by positioning the sub in line with the PC user and equidistant from the satellites but this arrangement may not be optimal for everyone.

I would look for sats that can meet the sub somewhere below 100Hz.

[joensd]

I wouldn't cross over at > 200Hz

I have this issue with my monsoon planar 14 PC speakers where the sub crosses over to the planar sats at around 200Hz.

The problem is that a 200Hz note is directional ie. you can locate where the sub is, ... I managed to overcome this issue somewhat by positioning the sub in line with the PC user and equidistant from the satellites but this arrangement may not be optimal for everyone.

I would look for sats that can meet the sub somewhere below 100Hz.

Yes, you are absolutely right. Should have mentioned that myself.
But also as you said positioning of a sub for the PC shouldn´t be too hard (and make a nice stand for a printer)or let´s say stereo subs are too much.

I am soon about to finish a ML-TQWT with the Tangband W3-871S which hopefully gives me enough bass ( down to 65Hz) to go without a sub. If I´m lucky with the setup I´ll be back soon.

[Timn8ter]

I've used the CSS Elf 1.5 crossed to a small sub and it sounded quite good. In fact, my neighbor crosses his to a DPL12 for his HT. Should make a very nice PC system.

[ozynigma]

Originally posted by Timn8ter
Do you have local distribution for Fostex? The 3 or 4 inch full-rangers would be very nice also.

Tim,

I have only been able to find Australian distributors for Fostex headphones, monitors and other studio gear, not drivers by themselves.

Thanks
Howard

[ozynigma]

Originally posted by coolkhoa
I don't know of a shielded ribbon, though some with low "leakage" may work.

Coolkhoa,

I am currently getting a price on these from the distributor.

They are shielded ribbon tweeters.

http://www.wagner.net.au/pae/Ventura/RibbonTweeter.htm

Thanks
Howard

[ozynigma]

Originally posted by 5th element
Open baffles simply will not work unless you are prepared to have pretty damn large panels next to your PC or lots of EQ to boost the bass, which small 3" low xmax drivers wont handle IMO.

How far an open baffle will go down is to do with the baffle size not the driver, obviously the driver will set how low the system can go, like in a normal box, but its before that that matters when diffraction takes place.

5th Element,

The drivers I am looking at all have Fs below 100Hz which is below the crossover point to the sub of say 150Hz.

I am completely new to the open baffle concept. Could you please explain what kind of response a small 4-5" driver will give in an open baffle?

Thanks
Howard

[ozynigma]

Originally posted by zobsky



I wouldn't cross over at > 200Hz

I have this issue with my monsoon planar 14 PC speakers where the sub crosses over to the planar sats at around 200Hz.

The problem is that a 200Hz note is directional ie. you can locate where the sub is, ... I managed to overcome this issue somewhat by positioning the sub in line with the PC user and equidistant from the satellites but this arrangement may not be optimal for everyone.

I would look for sats that can meet the sub somewhere below 100Hz.

Zobsky,

The sub can be crossed over as high as 150 Hz which is what I am aiming to do. So I am looking for the satellites to go down well below 200 Hz.

Howard

[5th element]

Originally posted by ozynigma



5th Element,

The drivers I am looking at all have Fs below 100Hz which is below the crossover point to the sub of say 150Hz.

I am completely new to the open baffle concept. Could you please explain what kind of response a small 4-5" driver will give in an open baffle?

Thanks
Howard

OK when the wavelength of the sound roughly reaches the width of the baffle sound diffracts round the edges. Now the wider the baffle the lower this happens. With a dipole when this happens the front and the rear wave cancel each other because they are out of phase with each other. Now my 30cm wide baffles start to do this at about 500hz and are 12dB down at 125hz and you dont want a 30cm wide baffle on your desktop.

[johninCR]

I use OB's on my desktop with really big nice sound and super cheap. You only need a 22" baffle width to get 150hz, but I'd go wider to have more flexibility with your sub's setting. All you have to do is fold back the "wings" and end up with a front baffle width the size of the speakers. In addition to being able to get great sound, you can do it super cheap. I use a 5 driver array of 4" TV speakers on each side with a total cost of $18 plus some duct tape. $15 for 10 drivers, $3 for some posterboard with the styrofoam sandwiched in the center. I got lucky and the cheapest 4"ers I found sounded the best.

An array will help cheapies sound much better than a single one because driver excursion is so much less for the same volume.

You can find decent sounding drivers in the $1-$3 range. If your really want them very close to your monitor you'll need shielded which might cost a little more. If you can get more than about 18" away from your monitor you'll get better sound and not need shielded drivers. With big tall sound you don't want a narrow soundstage.

Find a supply house that has replacement speakers for TV's, cars, etc. You can listen to a lot different speakers to find those you like in the 3"-5" range. For listening hold it in your hands and what you are looking for in addition to good overall sound is that they really come alive when you wrap your index fingers and thumbs around the outer edge to form a mini baffle. Look for extended upper range to avoid the need for a tweeter.

Spend $10 or so picking out a few different ones that you like the best. Then use cardboard and tape to make a test baffle to see how they really sound at home. Which ever you like the best, buy some more and put 4 or 5 of them in a column on the cardboard baffle as close together as possible. Fold the sides back for some stability and put it on a table, so your ears are in the vertical plain of the array and give it a listen. A/B it with whatever box speakers you have for a real eye opener. If there's not much bass don't worry. The key is do you like the sound that's there? Better vocals than you've ever heard before, big open sound, etc.

If you really need a tweeter, then pick up a pair of the cheap titanium bullet tweeters for cars for under $25 for a pair and an Lpad. I know they're quite harsh out of the box, but stuff small pieces of soft foam rubber (about the size of a pencil eraser) down between the sides of the horn and the center "bullet" cone. Start with 3 equally spaced and tune to taste. I usually end up with 6 leaving only small unfilled gaps. This will tame the harshness and really bring out the detail. You'll need the Lpad to lower their volume because they are very efficient. Mount them at ear level on your desktop baffles. They come with a cap, so you probably won't need any crossover.

Experiment with the baffle size. If you get lucky and end up with higher Qts speakers, which is common for TV speakers, then you can get even more of that great OB bass with longer wings and set your sub cutoff lower.

I'm still using by original test baffle. I guess someday I'll get around to making permanent baffles to improve the looks.

Import duties are a bear down here, so you should be able to find something good for even cheaper than I did if you shop around.

It's a fun, easy and cheap project that will be a real eye opener in terms of sound if you haven't heard an OB array before.