Level control for tweeter

[Augusts]

Hello.
A very technical question.

I have a SB acoustics 4ohm tweeter that I have calculated needs a 14db attenuation resistor network, however, I would like to put also a Level control for the tweeter. For example this one Monacor LP 100-8. The manual says 8 ohms +/- 25%. Then how can I calculate the attenuation in this case and how would I wire the Level control in the tweeter - L pad network?

Thanks
August

 

[Michael Bean]

Are you sure you need 14dB? That's a lot of attenuation!
This will help with the calculations LPad Driver Attenuation Circuit Designer Calculator...but that's a lot of attenuation and you might not like the answer you get because the required component values will be extreme.

Mike

 

[Augusts]

Not that extreme - 1 ohm and 3.2 ohm resistors. I measured the levels with pink noise and yes - to match the subwoofer @ 25hz, the tweeter needs 14db attenuation.

 

[Galu]

It appears that you intend to attenuate the tweeter with the two fixed resistors then provide extra control of the attenuation with the Monacor LP-100-8 L-pad attenuator. That is an unusual requirement.

Firstly, the LP-100-8 is only rated at 15W and I would recommend using the AT-62 rated at 100W. This should be able to do all the attenuation you need on its own without fear of overheating. It is wired as shown in the attachment.

MONACOR - Products - AT-62H

 

[Galu]

P.S. The AT-62H is the single pot version and presents a load of 8 ohm to the crossover network.

If you require to present a load of 4 ohm, then buy the AT-62ST twin pot version and simply wire the two sections in parallel.

MONACOR - Products - AT-62ST

 

[Augusts]

OK I'm starting to see the problem here and why people use active crossovers - to input 35w power into kickbass speaker that should have a 10db attenuation to match the sub - the resistors should be 200W 5,47 ohms and 60W 3,7ohms. That is insane but thats what the calculator shows.

Thanks for the answers

 

[Augusts]

I'm thinking I should maybe use an Equaliser? What do people do in this kind of situations? An amp block for the sub and add 10db gain for the sub probably

 

[Galu]

OK I'm starting to see the problem here . . .

So that the rest of us can see the problem, please supply full details of your intended project and your chosen drivers.

 

[bentoronto]

OK I'm starting to see the problem here and why people use active crossovers...

Makes no sense today not to have a DSP (Behringer DCX2496 does everything) and bi-amping. No sense at all. If you don't have a spare amp sitting around, go to the Salvation Army store and look for an amp for your tweeters.

Then get an inexpensive condenser mic, REW..... and then dial-in great sound.

B.

 

[Augusts]

Drivers are Lab12c, the box 12 280 8 w, SB Acoustics SB26STAC-C000-4. Cross frequencies are 62Hz, 1800Hz. Sensitivity 82db, 93, 92 - so maybe less attenuation for tweeter but still its 10db for the woofer. Lab 12 takes 300 watts, the box - 35watts, tweeter about 18 max.

I allready have a dsp and amps. The project was to build a passive crossover, but I am still in learning process, so its normal that I make a few mistakes making concepts.

 

[Galu]

Lab12c . . . Sensitivity 82db

The sensitivity of the LAB 12C is 89dB!

https://www.eminence.com/pdf/LAB_12C.pdf

 

[Augusts]

The sensitivity of the LAB 12C is 89dB!

https://www.eminence.com/pdf/LAB_12C.pdf

That depends on the enclosure.

Makes no sense today not to have a DSP (Behringer DCX2496 does everything) and bi-amping. No sense at all. If you don't have a spare amp sitting around, go to the Salvation Army store and look for an amp for your tweeters.

Then get an inexpensive condenser mic, REW..... and then dial-in great sound.

B.

I have chosen to use a dsp and seperate amp for the subwoofer, that solves the problem. Also then I can EQ the tweeter if needed.

 

[Galu]

For reference, the box 12-280/8-W driver has a sensitivity of 95dB

https://images.static-thomann.de/pi...cs/283965_c_283965_datasheet_v2_en_online.pdf

and the tweeter is 91.5dB.

SB26STAC-C000-4 :: SB Acoustics

 

[Galu]

That depends on the enclosure.

Please explain what you mean by that statement.

 

[mprivitera1]

Hi guys,
a simple clarification, I have this attenuator, MONACOR - Products - AT-52H if I understand correctly it is 8 ohms , it means that the amplifier sees 8 ohms, regardless if I connect to it, indistinctly, a speaker from 4ohm or 8ohm, correct?

 

[Galu]

The L-pad maintains a constant load impedance (8 ohm) for the amplifier or the crossover network.

The speaker impedance makes little or no audible difference to the attenuation..