How to make a speaker more forward sounding

[andy2]

I've just finished building Troels TJL speaker yesterday. The sound is slightly laid back, and on some recordings, very distant.
Here is the crappy picture so far :
http://www.geocities.com/hai_vu1/TJLBoth.jpg

I am thinking of modifying the xover to make the sound slightly more forward which better suits low-volume listening. More treble would help too. Here is the xover of the TJL:
http://home1.stofanet.dk/troels.grav...oudspeaker.htm
It is near the bottom of the document.

On his website, the measurement show a slight dip (1db or so) in the 1k - 3k area. I hope to bring it up to about +1db in that region. Can someone suggest a change in the xover?

On the plus side, the bass is very good -- tight, powerful, and very controlled. The treble is too relaxed though but I am playing around with the series resistor

[Ron E]

Assuming everything is wired correctly, the easiest way to add treble would be to reduce the value of the 4.7 ohm resistor in the tweeter L-Pad. This will raise the whole tweeter range. It looks to be a reasonably well designed crossover, I would try that before making any more extensive mods.

[sberube]

Not an easy feat, but in my (short) experience, lowering the order of the XO made a HUGE difference in brigning the soundstage forward. When I designed my last set of speakers, I had started with a 4th order on woofer and 2nd order on tweeter, and as I went along tweaking my filters, I remodeled them to use less and less componants, and the sound became clearer and clearer as well as more warm and forward.

But you have to be willing to model your own filters for that...

[SY]

I think what you want to do is to bring the tweeter level up about 2dB, then have it shelf downward 1 or 2 dB with a 10kHz turnover. You can do this with a series RC across the tweeter.

[andy2]

Originally posted by SY
I think what you want to do is to bring the tweeter level up about 2dB, then have it shelf downward 1 or 2 dB with a 10kHz turnover. You can do this with a series RC across the tweeter.

Could you elaborate a little bit more?

[SY]

Only a little more, since I don't have Calsod in front of me at the moment. Basically, I'm suggesting that you create a shelf in the frequency response by lowering the level of the top octave uniformly by 2dB with respect to the octave just below that, along with bringing up the entire tweeter level by 2dB. The net result is that you bring the trough from 5K-10K up a touch; this will make the sound more immediate and a bit brighter.

The easiest way to do that is with the network I suggested. If you think about it, at low frequencies, the C in the series RC (paralleled with the tweeter) acts as an open circuit, so the R does not contribute to the attenuation. At high frequencies, the C acts as a short, so that the R shunts the tweeter interacts with the series resistance feeding the tweeter, dropping its level. The transition occurs at f = 1/2piRC.

You'll need to do some crossover sims to get the right values, but it's do-able with a couple go-rounds with any good crossover CAD program. The one I use (Calsod) will actually do the optimization for you once reasonable starting values are plugged in.

[andy2]

How about reducing the 2.2mh inductor in the mid xover?

[SY]

Your dip is well above the range covered by the MR/woofer. It's solidly in tweeter territory.

[SY]

BTW, starting guesstimate values (NOT checked!) would be reducing the tweeter feed 4R7 to 3R9, increasing the shunt 5R6 to 6R8, and paralleling the tweeter with a series of 4R7 and 3uF.

[K-amps]

Originally posted by SY
BTW, starting guesstimate values (NOT checked!) would be reducing the tweeter feed 4R7 to 3R9, increasing the shunt 5R6 to 6R8, and paralleling the tweeter with a series of 4R7 and 3uF.

SY's solution of altering both 4R7 and 5R6 is better than merely reducing the feed 4R7; because changing just that one resistance (not both) will affect impedance and hence crossover point. By changing both R values of the L-Pad, you can safely affect only SPL and not worry about altering the crossover point. To begin with, I'd change the R values to the following:

( The current Value: 4R7 and 5R6 equates to a 7.7dB reduction or attenuation for a 8 ohm driver.)

1dB accentuation: 4.3 and 6.9 (i.e. 6.7dB attenuation)
2dB accentuation: 3.9 and 8.6 (i.e. 5.7 dB attenuation etc)
3dB accentuation: 3.3 and 11 ohms.

hope this helps.