DIY TA-7331-A here we go...

[RPMac]

Maybe I should build a coupe H frames for my 421's and try

The 7331’s are similar to the H-frame. You could try them as subs, but then, you would have to build something to replace them.

 

[MrEd]

I have a few more pairs of 12'' plus 421 and 416 woofers

 

[RPMac]

Something just came to me, from the front of the speaker cone to back on the H-frame is 34”.
On the SLOB (I really don’t know how to measure it) on what I have now, is less than 12”.
Going to have to make some changes….and buy some wood.

 

[MrEd]

Updated my crossovers again... funny how you think you have something nailed and then...🙄
I keep measuring and tweaking.
I started with some Crites autoformers but never liked the results.
Reading Dave Slagle's info about autoformers I decided to tray agin and use my l pads to add the resistor he recommends to correct the impedance. Works a charm and I'm istening right now, sound nice so far.

 

[MrEd]

Another step down the path .... I have a Jensen F12 in hand.
Hooked it up this morning to be sure it works.
I have made an offer on another that is a really good match ... fingers crossed

 

[MrEd]

Two Jensen F12's in the house.
Date code apear to be 1943 and 1947 , 341 and 736 , coils measure 680 and 700 ohms, voice coils are 6.9 ohm.
Tested both with 12 volt bench supply and test tones from my phone and they have equal output.

 

[MrEd]

Comparing the Jensen to Rola, Jensen on the right.

 

[MrEd]

One in it's new home.

Listening to them as I type.
I will do some measurements shortly.
Sounds good.

 

[MrEd]

Measurements

 

[MrEd]

With a fair amount of time listening I can say the Jensen drivers do out perform the Rola, not by any leaps and bounds, but in the upper range they are more refined.
This combined with a little more work with the Crites autoformers, and finding that my SE 2a3 amps have a synergy with the 12b4a preamp thats amazing in it self, I have reached new level with this project.
Can't ever remember having anything this good 😊
Now it's time to get on with my multiple subs project.

 

[doglv]

I'm not very REW fluent but it looks like the efficiency of the woofer is pretty darn high. Mostly north of 105db... am I reading that right?

Where are you crossing over? Sorry if I missed that.

 

[MrEd]

I'm not very REW fluent but it looks like the efficiency of the woofer is pretty darn high. Mostly north of 105db... am I reading that right?

Where are you crossing over? Sorry if I missed that.

I feel a bit inept with REW...
Never like it when it adjusted to really flat and I struggle to get repeatable measurements at a later time when trying compare changes.
I don't think the charts loudness is accurate.
I have the 299 driver attenuated by 7 db . I think these woofers are around 97 db with full 80 volts to the coil, this is with 60 volts.

 

[doglv]

Do you think that 100-200hz bump is room related? Which is typical, I think. That might not be a bad thing and definitely better than a dip.

 

[MrEd]

I do think it is the room.
To me it doesn't sound as bad as it looks on graph.
The suck out below is room also.
Maybe my brain is smoothing them...🙂

 

[MrEd]

@doglv ,
I forgot to answer about the crossover.
1st order low pass is about 1250 Hz. 1st order high pass is about 1800 Hz

 

[Billet]

I never pay much attention to graphs, but especially not in the bass region. That said, your graphs look fine to me. An interesting experiment is to measure your room without any audio. I suspect you will see your low frequency bump as background noise.

 

[MrEd]

I never pay much attention to graphs, but especially not in the bass region. That said, your graphs look fine to me. An interesting experiment is to measure your room without any audio. I suspect you will see your low frequency bump as background noise.

That's interesting, I will definitely try it.