Help! 2 way crossover filter

[koushik]

I have bought pair of Peerless DW69 tweeter and M10NG mid/bass driver for a pair of Bookshelf for my HT front L&R.

What should be the ideal filter ckt for this BS? Where should I cross them for these drivers?

My enclosure volume is 11.7 liter and ported tuning frequency is ~50Hz.

Thanks in advance.

 

[keith_correa]

My enclosure volume is 11.7 liter and ported tuning frequency is ~50Hz.

Not related with the crossover but are you trying for a EBS alignment with this? If yes, why? Don't you intend using a sub?

 

[hydrovac]

I have bought pair of Peerless DW69 tweeter and M10NG mid/bass driver for a pair of Bookshelf for my HT front L&R.

What should be the ideal filter ckt for this BS? Where should I cross them for these drivers?

My enclosure volume is 11.7 liter and ported tuning frequency is ~50Hz.

Thanks in advance.

The first step in developing a loudspeaker is obviously deciding what the goals are.

Size and Shape
Bandwidth
Directivity
Design Consequence

What is the basis for selection of these drivers?

11.7 liters is the Vas of the woofer. Vas is one of several well-known Thiele-Small parameters commonly associated with mid- and low-frequency moving-coil audio transducers (aka drivers.)

Vas represents the equivalent volume of air having the same acoustic compliance (i.e., stiffness or springiness) of the driver suspension in free air. In other words, it indicates the equivalent volume of air that would produce an air-spring with springiness (i.e., compliance,) equal to that of the drivers suspension; it is NOT the recommended box volume for a driver.

Combined with a couple of other important Thiele-Small parameters such as Fs, the free-air resonant frequency of a driver and Qts, the total Qwhich represents the effective system dampingof a driver at the drivers free-air resonant frequency Fs including all system resistances, you would then be able to calculate the proper loudspeaker enclosure volume for an individual low-frequency moving-coil driver with reasonable accuracy.

With the design goals in mind, the first step is to decide what kind of speakers will meet the technical requirements, budget and size limitations.

 

[koushik]

Keith, sorry I don't know what is EBS? I intend to use a sub of course. I am try to build something better than a basic satellite speaker for my HT. I will buy a sub later.

Hydrovac, the Vas that given in the site along with other parameters lead me to a volume of more than 18lt. I made than and found the sound to be bloated. Cone wobbling to much. In a little higher volume level it seems like it will destroy the drivers. Then I made much smaller enclosure. About 5lt. The thing got tighter. Drivers were looking good and safe. Was maintaining its stiffness at moderate to high volume but the bass extension got the beatings. Then I made this volume. At the average of previous 2 enclosure volumes. Now things have fallen into places. I used only a 10uf BP capacitor to feed the tweeter above 2500Hz.

So, this the story. I hope that make sense.

 

[SIDEWINDER18X]

I used only a 10uf BP capacitor to feed the tweeter above 2500Hz.

Don't use a single pass capacitor arrangement for the tweeters. That's a 6db/octave approach. Tweeter will not sound clean.
Follow this schematics. You shall get towards your goal. It's an asymmetrical arrangement ...... 6dB/octave for your LF/MID & 12dB/octave for HF, crosses at 3kHz.
The lamp is 12V/35W low resistance lamp (> 0.5ohms). It works as a limiter. Is a must for small sized drivers.
If you want I can provide you coil winding details for that 0.3mH & 0.6mH inductors.

 

[doors666]

looking at the tweeter graph, 4k looks like a good point.. no graph for the woofer, can you post one.

 

[keith_correa]

IMO, acc. to the TS parameters given on the DIYAudioCart site, that driver likes a ~16litre box tuned to ~69Hz.

 

[koushik]

If you want I can provide you coil winding details for that 0.3mH & 0.6mH inductors.

Please tell me the details in terms of SWG measurement. In Kolkata, they seems to know the value of wire gauge by SWG and not AWG. Do you know any better place to procure the copper wire for smaller projects like this. Behind the Chandni market there is a place where they only sell in rims or atleast 500gm.

 

[koushik]

looking at the tweeter graph, 4k looks like a good point.. no graph for the woofer, can you post one.

Sorry doors666, nothing more I have than that is available in that site

IMO, acc. to the TS parameters given on the DIYAudioCart site, that driver likes a ~16litre box tuned to ~69Hz.

Yes, that is correct. I got something like 16Lt. It was few months back, so I forgot the exact number. I used the calculator available in diyaudioandvideo.

But believe me, that is not sounding good. It is wobbling like anything. I think, the Vas that is given in the site is not correct. Some typo is there. I compared with lots of 4" mid/bass driver from different brands and none is having so high Vas. Then I decided to cut down the volume and it started working for me.

 

[keith_correa]

Something is definitely wrong with those parameters. Look at the parameters of this and this. They are exactly the same.

Check this thread. Maybe you can send a PM to the person who built his speakers using these drivers - he may have measured them.

I suggest that you do not build using trial/error - it will be definitely be sub-optimal.

Check to see if any FM in Kolkata can measure [FR, IMP & TSP] for you.

 

[keith_correa]

And to reply to your original Q, IMO - between 3K & 4K is a good point to cross.

 

[palka]

IMO, acc. to the TS parameters given on the DIYAudioCart site, that driver likes a ~16litre box tuned to ~69Hz.

But believe me, that is not sounding good. It is wobbling like anything.

Can this wobbling be explained by the fact that you tuned the box at 50Hz?

 

[SIDEWINDER18X]

Incorrect box tuning. That tiny driver is not optimized to work at 50Hz. The cone in that driver will rock at 50Hz due to smaller suspension spider and surround profile geometry design. Try a higher frequency. Try something around 80 - 120Hz.

 

[sashijoseph]

This here is the correct link to the driver specs.
Products - PeerlessAudio.com

Simming reveals a ~7-litre volume and ~75Hz tuning to be good at a max of 15-20W power.

This driver would be well suited in a 3-way.

And since this midrange extends well into about 7KHz,the tweeter could be crossed higher at ~5kHz.

 

[koushik]

That is not the same driver. It doesn't look like the one that I have, and also it has 8 ohm impedance.

 

[sashijoseph]

Heck...yes it doesn't look the same.
But the model no. on the FR graph says M10NG(BM)!!!

Is your driver a 4ohm model...the DC resistance says 5.8 ohms(diyaudiocart spec),so it is more likely a 8 ohm(nominal) driver.

regardless,you could lower the volume of the box by stuffing in a couple of voluminous books or sth and tune the port bit higher (75-80Hz) and look whether things improve.

 

[koushik]

Yes my driver is 4 ohm written on the driver as well as in the site's spec.

I was thinking of tuning it higher and cross the tweeter bit higher as other members have suggested. I will also put some stuff inside to reduce the volume as you said. Will get back with the result.

 

[saheb11123]

So did you make three boxes? Each for 5lt , 16lt and 7lt design?
And what did you do with those?

 

[diesel engine]

Don't use a single pass capacitor arrangement for the tweeters. That's a 6db/octave approach. Tweeter will not sound clean.
Follow this schematics. You shall get towards your goal. It's an asymmetrical arrangement ...... 6dB/octave for your LF/MID & 12dB/octave for HF, crosses at 3kHz.
The lamp is 12V/35W low resistance lamp (> 0.5ohms). It works as a limiter. Is a must for small sized drivers.
If you want I can provide you coil winding details for that 0.3mH & 0.6mH inductors.

But as far as I know, limiting is needed in the HF (tweeter) circuit. people always use more power for the woofer than a tweeter in a biamped system.

 

[koushik]

@Saheb, its 16lt, 5lt and now 11lt. I used the materials of 16lt to make the 11lt and 5lt enclosure is lying with me. Hoping to make something for very casual listening.