How to attenuate woofer

[AndrewUK1990]

Hi everyone, i was just wondering if anyone could give me info on how to reduce the output of 2x bass units in a 3 way loudspeaker i have by 3dB. Currently they sound quite good but the bass is slightly too strong due to the fact the 2x 6.5" bass units that are in each cabinet are rated 90dB sensitivity while the midrange is 87dB. The tweeter is 90dB and seems to be operating ok, but it wouldnt be intrusive if it would become a little more apparent.

Thanks in advance!

[sreten]

Hi,

Try wiring them in series with c/o mods, and knocking back the tweeter to the midrange.

rgds, sreten.

Your numbers are wrong. At 90dB each they would be 96dB in parallel albeit 4ohm presumably.
In series they will be 90dB 16 ohm presumably, which is fine, in reality around 3dB of BSC.

[cyclotronguy]

Custom tapped autoformer

[AndrewUK1990]

thanks for that, but i really should have provided more info. I meant to say that the rated sensitivity of the bass units is 90db and they are wired to the crossover in series, 4ohm each to make 16ohm at crossover. So im assuming that what you basically said is that in this config they end up producing around 87dB because of a -3dB BSC. In that case they do infact match up to the same as the midrange which is 87db. So are they ok wired as they are? It could be the small room im in that makes them sound a bit coloured tbh.

[AndrewUK1990]

also the 4ohm drivers wired in series will present an 8ohm load to Xover not 16ohm no?

[badman]

Yes, that's correct re: 4+4=8. If it's overpowering, try placement tweaking- pull them out further from the rear wall. If you still have too much bass you're in an enviable position- too much is better than too little, you can use line-level EQ to make a shelving filter, essentially a tuned capacitor and resistor in parallel, in series with the amp input. The capacitor sets the filter frequency, the resistor the level of the shelf.

[AndrewUK1990]

ahh right ok, cheers for that, i wasnt aware you could do that. Ive heard about using Lpads and such before though; but only on tweeters. Is it possible to use on woofer or not reccomended for some reason? and does a Lpad have any effect on the impedance load seen by the Xover?

[DougL]

ahh right ok, cheers for that, i wasnt aware you could do that. Ive heard about using Lpads and such before though; but only on tweeters. Is it possible to use on woofer or not reccomended for some reason?

An Lpad will reduce the damping seen by the woofer. This can alter the box tuning, frequency responce and transient responce of the woofer. (For better or worse)
Not usually the optimum solution.

[CLS]

3way, 2x 6.5" bass + 87dB mid + 90dB tweeter

Hmmm.... I don't like that mid in this application, no matter what it is. (if it's actually a small wide-ranger, use it else where)

How about... er... get rid of the mid, and make a MTM ?

[AndrewUK1990]

The mid is a high midrange with crossover points set at 800htz - 5khz. It actually sounds very natural and reproduces voices and guitar notes spectaculaly well for its age. I know this because the speakers i have were old wharfedales - and the only thing ive kept original are the mids due to the other drivers/Xover needing serious repair work.

In other words, ive kept the cabinet the same, and used the same Mids, or im trying to anyway, the bass are scanspeaks 18w/4531G00's and the tweeter is D2905/950000 and the Xover has been upgraded with new better components to suit. Im thinking an alternative would be to try find some 3.5" mids with similar charactristics but at 90dB response to flatten out the overall freq response. Anyone got any view on this - or should i just do as badman said and use a line-level EQ?

Heres a crappy pic of one cabinet so you can see what it looks like and drivers/placement etc. - sorry for the quality.