What can I build with these?

coldcathode

Member
2009-01-11 4:31 pm
5.25" Audax HT130K0 (1 pair)
25MM Audax Tweeter TMO25F7 (1 pair) all NOS

The curves look like an XO point around 2200Hz would be nice. I want to bi-amp these with 24dB L/R active crossover (all tube) with approximately 15-20 Watts (PP tube) per channel for both mid and tweeter.

The low end (subwoofers) will have significantly more power available as they will be driven with Parallel - Push Pull chip amps. (separate topic) but about 300 watts/channel at full song. (OVERKILL anyone?)

The 2-way sub XO is a simple active OP-Amp again with 4th order L/R alignment.

Crossover points have not been determined and are up in the air as they two XO's are just bare boards right now.


My questions are as follows:

Since I have a "blank slate" to start with (just the drivers right now) what type of enclosure should I look at for the mid/tweeter setup?

Vented will give me better low end but if I am using sub's where do I tune the box to? any "rule of thumb" as to how much above or below the XO point to set the box's -3dB point?

The drivers have an Fs of 44hz so maybe a sealed enclosure would also work?

As far as the subwoofers go I have plenty experience with building enclosures for those I just need a little advice on the overall topolgy of the system.


BTW, this will be in a relatively small listening space or a "man cave" so to speak, so overall the 90 dB SPL is more than enough even with the relatively low power of the tube amps.
 

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I'd crossover slightly higher, ~ 3Khz, passively. The main benefit of bi-amping, reduction of intermod distortion, comes at the woofer - mid crossover point.
I'd go sealed, unless you plan to use the mid-woofer- tweeter combo as a stand alone system at some point. You can always close off the ports when required.
At the low end, I'd use good Woofers, not subs, crossed over 1st order, which will allow easy baffle step correction.
 

coldcathode

Member
2009-01-11 4:31 pm
I'd crossover slightly higher, ~ 3Khz, passively. The main benefit of bi-amping, reduction of intermod distortion, comes at the woofer - mid crossover point.
I'd go sealed, unless you plan to use the mid-woofer- tweeter combo as a stand alone system at some point. You can always close off the ports when required.
At the low end, I'd use good Woofers, not subs, crossed over 1st order, which will allow easy baffle step correction.

Pete,

Good info, here's a thought, What if I were to design things around the woofer/tweeter as being a standalone system, with bi-amping (I have the tube amps 1/2 built along with the tube XO) and then have the sub/woofer setup be more of a "helper" to the low end and be easily level controlled it would help a lot with the WAF (wife acceptance factor) LOL.

I build all my own hardware so the 2 way Sub XO could be "switchable" in and out along with powering up the subs. Would I tune the 5.25" woofer box as if there were NO sub and then let the XO blend the two?

BTW, my current system that I am using as my listening/computer speaker seup is a tube amp and some Yamaha monitors, along with a 10" ported sub box and plate amp. The sub is 18db/Octave @ about 70hz and the yamahas just roll off natural. I like the sound but there is a definate midbass "hump" near the XO point since it's only a low pass filter.

The overall goal of the system is to replace this existing layout with better components and better design.