Hi Guys,
I've been messing with a pair of these using the stock CPA-15 Crossover pictured. I have a pair of active JBL 2235's on the bottom for bass which are crossed over at about 100hz so I am not concerned with wringing low bass from the Tannoy. I find I get the best transition using the Tannoy 15 in a sealed cabinet but I feel like a lose a bit of output in the range that the bass driver on the tannoy is covering by having it sealed. Plus they were designed that way as they were used Soffit mounted. So I wanted to try to bring down the output of the tweeter on the Tannoy so I will get more impact from the bass unit of the Tannoy in the 100hz to 800hz that it is covering. Do I just increase the 2.2 ohm resistor and decrease the 5.6 ohm? I'm thinking lowering it 6db would be a good start. Any recommendations on values?
I've been messing with a pair of these using the stock CPA-15 Crossover pictured. I have a pair of active JBL 2235's on the bottom for bass which are crossed over at about 100hz so I am not concerned with wringing low bass from the Tannoy. I find I get the best transition using the Tannoy 15 in a sealed cabinet but I feel like a lose a bit of output in the range that the bass driver on the tannoy is covering by having it sealed. Plus they were designed that way as they were used Soffit mounted. So I wanted to try to bring down the output of the tweeter on the Tannoy so I will get more impact from the bass unit of the Tannoy in the 100hz to 800hz that it is covering. Do I just increase the 2.2 ohm resistor and decrease the 5.6 ohm? I'm thinking lowering it 6db would be a good start. Any recommendations on values?
Attachments
@Zen Mod your local resource for Tannoy fans.
In the mean time try looking this thread over…
So, sometime in January I bought these classic 30 year old Tannoy CPA12’s after MZM identified the hidden treasures within: Dual Concentric 12-inch 3134’s. To top it all off, MZM has a ML box for these fitting my living room perfectly. And the price was unbeatable @ 500 dollars including an extra tweeter.
But, surprises kept coming. These pics show the drivers upon arrival at my house. Notice the baskets have been painted, and this had been spilled onto the surrounds and in some places also onto the cones.
One of the drivers have had a party with a lit candle. So, these are...
ZM is a fan of the CPA 15 crossover and I think there is some discussion of tweaking tweeter values in that thread.
In the mean time try looking this thread over…
So, sometime in January I bought these classic 30 year old Tannoy CPA12’s after MZM identified the hidden treasures within: Dual Concentric 12-inch 3134’s. To top it all off, MZM has a ML box for these fitting my living room perfectly. And the price was unbeatable @ 500 dollars including an extra tweeter.
But, surprises kept coming. These pics show the drivers upon arrival at my house. Notice the baskets have been painted, and this had been spilled onto the surrounds and in some places also onto the cones.
One of the drivers have had a party with a lit candle. So, these are...
ZM is a fan of the CPA 15 crossover and I think there is some discussion of tweaking tweeter values in that thread.
The 3836 is the 15" dual concentric driver from the Tannoy CPA-15 speaker.
We are looking at the CPA-15 crossover on the right of the attachment.
I believe it is the 2.2 ohm resistor that is responsible for attenuating the tweeter - the crossover experts will soon deny or confirm!
We can try increasing the value of that resistor to 4.7 ohm to note the reduction in the tweeter's output.
If that results in insufficient attenuation, we can replace the single attenuating resistor with an L-pad arrangement of two resistors.
A 3.9 ohm resistor would take the place of the current 2.2 ohm and an 8.0 ohm resistor would be wired directly in parallel with the tweeter.
This L-pad arrangement would give an overall attenuation of 6 dB (assuming the nominal impedance of the tweeter is 8 ohm).
We are looking at the CPA-15 crossover on the right of the attachment.
I believe it is the 2.2 ohm resistor that is responsible for attenuating the tweeter - the crossover experts will soon deny or confirm!
We can try increasing the value of that resistor to 4.7 ohm to note the reduction in the tweeter's output.
If that results in insufficient attenuation, we can replace the single attenuating resistor with an L-pad arrangement of two resistors.
A 3.9 ohm resistor would take the place of the current 2.2 ohm and an 8.0 ohm resistor would be wired directly in parallel with the tweeter.
This L-pad arrangement would give an overall attenuation of 6 dB (assuming the nominal impedance of the tweeter is 8 ohm).
isn't the combination of the 2.2 and the 5.6 already an Lpad? Thats why I was thinking of increasing the 2.2 and decreasing the 5.6.
The 5.6 ohm is not combined with the 2.2 ohm as is required to produce an L-pad. Besides the numbers don't compute.
To look like an L-pad, the 5.6 ohm would be wired directly in parallel with the tweeter following the series 2.2 ohm resistor.
I believe the 5.6 ohm resistor is placed in series with the inductor to alter the Q of the filter - or something like that - don't quote me!
To look like an L-pad, the 5.6 ohm would be wired directly in parallel with the tweeter following the series 2.2 ohm resistor.
I believe the 5.6 ohm resistor is placed in series with the inductor to alter the Q of the filter - or something like that - don't quote me!