Boston Acoustics T1030 Crossover Schematic and Info

[Pete B]

I read Don Keele's review of the T1030 when in was published in Audio in 1991 starting on page 81 in the .pdf here:

Audio-1991-01.pdf (worldradiohistory.com)

Took another look at this test report and the T1030 looks to be 6 dB down at 40 Hz which is a 

bit much, boosted high pass EQ would make sense to bring it up by 3-6 dB to get a flatter response.

Figure 8 in the test report shows that the system resonance (Fc) is at about 40 Hz and that the

impedance dips to 3.4 ohms around 100Hz indicating that the bass section is 4 ohms even 

though the system is rated as 8 ohms.

I liked this design, very nice work and always wondered what the crossover design looked like.

Bought a pair of crossovers on ebay, measured the inductors and here is the schematic:

 

[moke66]

This is a great help thanks! I'm going to try this crossover in my T1000's and see how it goes for fun. You don't still have yours around you could sell or lend?

 

[Pete B]

Sorry I used the big inductors in another project.

[bjmsam]

On 11/29/2022 at 2:57 AM, Pete B said:

I read Don Keele's review of the T1030 when in was published in Audio in 1991 starting on page 81 in the .pdf here:

Audio-1991-01.pdf (worldradiohistory.com)

That review states, "Crossover Frequencies: 400 Hz and 3 kHz."
This summary states, "crossover points 250 Hz and 2,500 Hz."

Which is correct?

 

On 11/29/2022 at 2:57 AM, Pete B said:

Figure 8 in the test report shows that the system resonance (Fc) is at about 40 Hz and that the impedance dips to 3.4 ohms around 100Hz indicating that the bass section is 4 ohms even though the system is rated as 8 ohms.

Thanks for the schematic!  The upper section and lower section appear to be independent (like the AR9's crossover); would the upper section behave differently with the lower section removed?  Do the two sections work together like parallel resistors?

Req=R1×R2 / (R1+R2)