To make it easy I've drawn the P13 + D27 design which differs from the Esquire by having a narrower baffle and a tad taller. There is more than enough info there for any newbie to build. The port is in the rear and as long as there's about 40-50mm clearance to the wall, the port will work OK and give the bass some reinforcement. The 5uF cap should be at least metallised polypropylene. Damping material should be used on the back wall as a minimum.
Before doing any holes or rebates, please check sizes against actual drivers as there could be variations.
This is the original drawing for the P13 + D27
https://www.diyaudio.com/forums/attachment.php?s=&postid=308661
This design was looked at again to see if there could be any improvements in the bass which is lacking as one would expect (this design is about the mids and upper bass). The results were that the box as drawn is about right for a small bookshelf speaker and any larger would reduce the F3 value but at the cost of increased cone excursion, higher vent velocity, decreased power handling. Built as is gives the best overall box performance for the vented bookshelf but if more is required then the TLb (Transmission Line) is a great option.
x. onasis did try an alternative series crossover which was found to be an improvement on the single cap. This series crossover used:
R1=10R 5W resistor
L1=0.7mH inductor (DCR < 0R28)
C1=3.3uF metallised polypropylene capacitor
Tweeter -ve polarity
During the rethink of the box design, another series crossover was designed which IMO would be better than the one given to x. onasis originally. This series crossover used:
R1=6R8 5W resistor
L1=0.70mH inductor (DCR < 0R28)
C1=3.3uF metallised polypropylene capacitor
Tweeter -ve polarity
Schematic and more values can be found on post #179
https://www.diyaudio.com/forums/showthread.php?postid=1005310#post1005310
or alternatively an AR series crossover:
R1=6R8 10W resistor
L1=0.11mH inductor (DCR < 0R06)
C1=22uF metallised polypropylene capacitor
L2=1.2mH inductor (DCR < 0R28)
Tweeter -ve polarity
Schematic of the AR series crossover can be found on post #180
https://www.diyaudio.com/forums/showthread.php?postid=1005316#post1005316
As with all these crossovers, they are a good starting point that will give good sound but it is up to the builder to tweak and learn to get a better understanding and sound. Information on the series crossover schematics can be found by searching the web and no link is given as they can disappear. Just make sure you use an inductor with the lowest DCR you can afford.
October 2006 saw another and the last rethink on this design. A larger box was used to allow the speaker to produce some mid bass to try and give a better tonal balance and the results give an F3 around 60Hz. There is trade off of course as mentioned above, but speaker design is about compromises and the ones you are willing to accept. I found this acceptable as it became a better speaker for it's intended application.
A pic of this speaker can be found here:
https://www.diyaudio.com/forums/attachment.php?s=&postid=1040262&stamp=1161843995
The drawing of the new box is shown here:
https://www.diyaudio.com/forums/attachment.php?s=&postid=1040264&stamp=1161844087
It has been reported that the AR crossover is the nicer sounding but I used the revised standard series (6R8, 0.7mH, 3.3uF) as I had some high quality components that needed a home.
Have fun.... rabbitz
