HT-12+ Upgrade Crossover

Creating a separate thread for this as not the clutter the main HTM/HT thread.

There seems to have been some confusion about this crossover and I've edited the description below to try and clarify things:

The HT line was initially designed as high value home theater speaker kits with maximizing price to performance as one of the main goals. As such the the crossover was designed to squeeze as much out of a fairly simple and easy to assemble design as possible.

More recently I was asked by a customer if there were any upgrades that could be done to the crossover as they would not mind paying extra to improve the audio quality if that was possible. I had recently finished up a new speaker testing turntable and knew that with the improved measurement ease and detail that I could fine a way to smooth out the response further especially if they didn't mind paying for a larger and more complex crossover. Thus the HT-12+ upgrade crossover was born.

This upgraded crossover takes it from 8 to 19 components and makes for improvements to the frequency response of the HT-12 especially in the upper midrange and treble along with some minor balance adjustments resulting in improved sound quality and detail especially in for upper midrange and treble.

This crossover is not intended to become a replacement for the stock crossover sold with the HT-12 kit which still offers the best value and performance for the dollar. In fact everything this crossover does could be achieved through manual EQ. This crossover is offered this solely as an optional upgrade for those who don't mind paying a little extra for a larger more advanced crossover which help to improve the passive frequency response and sound quality of the HT-12.


There are a few options available, if you want to purchase or upgrade your crossovers.
1) - Fully assembled boards for $-- each + shipping.

2) - Fully assembled boards for $-- each + shipping. Discount price if you have an un-assembled kit and can send in the current stock set of crossover parts.

3) - PCB + loose crossover parts $-- each + shipping, everything need to assemble the new crossover yourself. Or $-- + shipping if you have not assembled your original crossover and can use the three components shared between the upgrade crossover and the stock crossover.

4) - Just the bare PCB with parts list for $12 each ($10 each for 2+) + shipping. This way you can purchase the required parts and assemble the crossover yourself.



Measurements of the HT-12 with the new crossover:

Measurements taken outdoors at 2m, 14ms gate, 1/48th octave smoothing, SPL scaled to 2.83v/1m level. Blended to diffraction adjusted nearfield LF response below 200hz.

HT-12+ CTA-2034-A Data
HT-12+ Full Polar Data

Link to the full set of measurements for this design.

Comparison to the normal HT-12 Crossover (ignore the difference below 200hz, different measurement methods):

 

There are three parts which are shared between the original design and the upgraded crossover, the 3.0mH inductor, and the 15 and 17uF NPE caps.

It would be $50 + shipping for the bare PCB & crossover parts if you wanted that option. $45 each + shipping if you do not need the three components that are shared between this design on the original.

 

I just ordered the PCBs for these so I expect it will be a couple weeks before those come in. I'll be sure to post here when those boards do come in.

 

Boards arrived earlier then I expected. I still need to grab some photos but I've got a few sets of parts here and could start taking orders for them.

 

I've sent you a PM.

 

Got an extra shipment of parts in and am now starting to assemble a few of these. Here is a quick photo of the assembled crossover:

 

I have two of the bare PCBs left.

 

The current HT-12's use a new Celestion woofer, I did design an upgraded version of the crossover for the new version but I haven't had any PCBs manufactured yet.

Here are the measurements for the two:
New HT-12 (Standard/Stock crossover)
New HT-12 (Advanced crossover)

 

I did have a few PCBs manufactured for the upgraded crossover of the current version of the HT-12 (Celestion woofer) if anyone was interested.