My dad and I just finished up my first little DIY project. It is an Adire Audio Kit LCR center channel. The kit price seemed a bit steep to me, so I went ahead and found the rough plans for the kit online and acquired similar spec'ed parts around and built the cabinet to fit.

The main modifications were instead of Adire branded Extremis 6.8 woofers I used a pair of Tang Bands (W6-1139SG). The differences were minimal in the specs between the two woofers and I couldn't quite justify the price differential for the Adire branded woofers.

I also swapped the shown clarity caps on most of the plan sets for Solens. Aside from these two, all the other drivers, resistors, and coils are to spec according to brand and type.

The cabinet was made by my dad, and was built according to the CAD drawings that were available for the kit. The only qualm he had with the plan set was that the midwoofer and the tweeter both cross into the top and bottom sections of the box and you end up having to make a bit of a cut into them in order to countersink the two drivers. Also the double front baffle wasn't really well documented in the diagram as intentional, he had never seen this so he was kinda questioning if it was drawn correctly.

The entire finished unit weighs in at 55 pounds on the scale which is massive! I've never felt a speaker this heavy. Feels very solid. Sounds even better!

I suppose a lot of the DIY groups know how great these projects sound compared to conventional speakers but I'm impressed.

We finished the outside of the speaker (3/4" MDF) sanded with 400 grit paper with sanding sealer first then sprayed 5 coats of satin black.

I can't quite submit any pictures yet of the entire rig since I've yet to post 5 posts, but I figured maybe I'd describe it and then get to answer a few questions and get an opportunity to send some pictures up.

It's good that you did a project like that with your Dad. But switching out drivers is not easily accomplished without wholesale changes in the crossover component values, as well as changes in the enclosure type and/or air space requirements. Here are some glaring differences between the Extremis and the Tang Band that you used: Re for the Extremis: 7.02 ohm, yours is 3.6 (8 ohm vs. 4 ohm). This alone drastically alters the crossover frequency which you had hoped to achieve by using the parts as listed. Another factor is Vas, which is 33.2 liters in the Extremis but only 11.78 liters with your woofers. This parameter is an important calculation in arriving with the proper box airspace.

Switch drivers or other components in a described kit ONLY if you have the knowledge and have done the research that is required. With any switch of components is the necessity to learn and use the design programs that will enable you to see differences with these changes. There is no doubt that if you had used the prescribed drivers this system would sound much better, although I am glad to hear that it sounds good to you as it is.

The thing to do, though, is to bite the bullet and procure a pair of the Extremis 6.8s. Replace the Tang Bands and everything should (from what you've written) be hunky dory. The change in brand name of a capacitor, as long as it is the same value and is a premium type, should be okay.

In addition to what's already posted, the TangBand's are -3db less efficient and their Le is ~2.5 times higher.

So there are major problems with this speaker as built.

There is no cheap fix other than to try wiring the TB's in series to create a 8 ohm load. Then adjust the resistors to pad down the MT drivers. I have no idea how this 'fix' will sound.

Sounds like I've buggered this up a bit. What is the audible difference in these Tang Bands being in the incorrect box size? They sound fine to my untrained ear I suppose...I guess my question is what should I try to hear that would be different between these and the Extremis?

The resistance being lower on the Tang Bands (4 ohm versus 8 ohm), could this not be fixed via simply adding a 4 ohm resistor in line to the circuit? What would the difference be that I would hear from adding resistance in the circuit?

Adding an inline resistance of 4 ohms is simple but re-purchasing a pair of drivers at this point would add huge costs to this project. I guess I just need some assurance that it would be audibly different to the point to justify the extra $200 investment into the project.

I guess also I'm asking because I get lost, rather quickly when people start discussing T/S parameters and how they relate to much of anything. I've always just built the boxes according to a given woofer's pre-made box specs from JL or ID for example in car stereos. This seems to require that you understand them more fully.

Cant call it an Adire LCR when everything you used is different from the design. XO parts are designed to work with the specific components and enclosure size and driver positioning.

If cost was a major factor, did you check the designs over htguide?
http://www.htguide.com/forum/forumdisplay.php4?f=39

Sounds like I've buggered this up a bit. What is the audible difference in these Tang Bands being in the incorrect box size? They sound fine to my untrained ear I suppose...I guess my question is what should I try to hear that would be different between these and the Extremis? For the woofers you have a completely different crossover point than the original design. In addition the MT output level is matched to the Extremis. So your MT are playing 3dB louder, that throws off the tonal balance.
The resistance being lower on the Tang Bands (4 ohm versus 8 ohm), could this not be fixed via simply adding a 4 ohm resistor in line to the circuit? What would the difference be that I would hear from adding resistance in the circuit?1/2 the amplifier power will go into those resistors.
Adding an inline resistance of 4 ohms is simple but re-purchasing a pair of drivers at this point would add huge costs to this project. I guess I just need some assurance that it would be audibly different to the point to justify the extra $200 investment into the project.Try wiring the TB in series, that's a poor compromise, but it will be much closer than what you have know.

IMO you should bite bullet and get the Extremis woofers. Then you'll have a speaker done right.

I guess also I'm asking because I get lost, rather quickly when people start discussing T/S parameters and how they relate to much of anything. I've always just built the boxes according to a given woofer's pre-made box specs from JL or ID for example in car stereos. This seems to require that you understand them more fully. There's a big difference between car and home audio. The design of a good home speaker is quite complex

The important thing, agent smith, is that you've made your start in DIY and had a good partner, to boot. Your project experience is more the rule than the exception for a first time try, so congratulations for getting as far as you have. From experience, those of us who have responded to this thread know that there is no easy fix that will enable you to keep the drivers as chosen. A whole new set of rules apply when you switch drivers, which is why DIYers who build a kit use exactly those components described in the kit. DIYers who design from scratch have a two-fold task (at least): knowing what design programs to use and how to use them while picking and discarding countless drivers and crossover designs to reach the end result; and then, knowing about and counting on the tweaking that happens afterwards. Tweaking can run the gamut: from a wholesale discard of the original design to adding just a db of padding to a driver. It's all part of the enjoyment of the experience of building to get to the result of purely wonderful sound.

Enjoy this center channel as it is while you work to save up for the right midbass woofers this kit is designed for. It is simply the best way to complete this project. You will realize the difference in SQ when that happens. Later, you can start working up a design for those Tang Band subwoofers. They could work together as a subwoofer in a home or car environment. Or just keep them in a dry place until such a time as you have built up your abilities to use them the best way, whether for yourself or for someone else. Meanwhile, no harm will come to the speaker while using it. Good luck and stick around with the forum, and start picking up on tips and design programs to start studying.

Few new questions and some photos. I've plotted out both driver sets in WinISD using the T/S parameters for both drivers. The gain and SPL graphs show interesting data. The gains are nearly dead on for both drivers with exception to the the Tang Band has a steeper sloping line on the rolloff and a bump on the end.

http://img182.imageshack.us/img182/631/gainad7.th.png (http://img182.imageshack.us/my.php?image=gainad7.png)

The SPL graph shows what I would guess...is the result of the inefficiencies of this speaker in terms of it being unable to produce the db output that the Adire woofer can, all things being equal 86 to 89 db favor going to the Adire.

http://img404.imageshack.us/img404/2112/splcu0.th.png (http://img404.imageshack.us/my.php?image=splcu0.png)


My question is, the gain graph shows that the Tang Band speaker seems to be able to produce a very similar graph shape that the Adire speaker with a slightly smaller box. Changing the box volume, the peak can be totally removed and the curves can nearly be lain one atop the other.

The SPL seems that it will never be accommodated since the woofer is less efficient out of the box when you get them both given the 1W/1M SPL numbers for them both.

So question, in the end graphs now seen, do you think it's worth going after 3db for 200 dollars?

Here are two photos of the monster (I'll take better ones when I find a cam to borrow)
http://img81.imageshack.us/img81/8136/dsc00655nl0.th.jpg (http://img81.imageshack.us/my.php?image=dsc00655nl0.jpg)
http://img406.imageshack.us/img406/8962/dsc00659tw8.th.jpg (http://img406.imageshack.us/my.php?image=dsc00659tw8.jpg)

3dB = double the power

Those WinISD plots are anechoic simulations not real world measurements.

The main problem is the woofer crossover point isn't where it's supposed to be...Ignoring other variables, the design is for an 8 ohm load creating a 700Hz crossover point. What you have is a 4 ohm load, that shifts the crossover point down a full octave to 350Hz.

So you have a 350Hz crossover point for the woofer and a 700Hz crossover point for the midrange. That means a big hole in the frequency response between 350Hz and 700Hz

That's the response I've been looking for...that makes more sense now and puts things a bit more into perspective. Thank you

Well it's really cool that we have some people here actually doing their own speaker designs. Even though you should have checked in with the DIY gurus in this forum and HTguide before experimenting (it can tend to save you from some headaches) It is what it is; experience. Maybe the next DIY you do can be a well researched experiment of your own design or an already concrete and well-tested design.

But hey, I don't doubt that your experimental speaker sounds better than most commercial speakers of the same price so as the other poster said, enjoy it!

There's a big difference between car and home audio. The design of a good home speaker is quite complex
So is the design of a good car audio system.

My dad and I just finished up my first little DIY project. It is an Adire Audio Kit LCR center channel.


From reading other's responses, it seems to me they are rather dis-approving. I think you just built yourself a totally sweet set of speakers.

If you're really looking for advice on your build, I'd say this: you should fix the crossover frequencies based on actual measured electrical values, and you may need an attenuation circuit. You need to fix your crossover, not replace your drivers.


I went all active crossovers on my music system, bi-amped, with a amp per driver, 2 way design. That's another option for you, but you'll be putting money into amps and an active crossover.

I'm preparing to build an upgrade on the HT system, and am looking at the extremis 6.8's in conjunction with ribbon tweeters (Aurum Cantus). I really dig the Adire XBL^2 designs, and will stick with them.

I actually have an extra Brahma 12" around, and I'm not sure if I won't replace my Hsu Research 1220HO with it.

3dB = double the power

Those WinISD plots are anechoic simulations not real world measurements.



Just to add to what Thomas said, WinISD, Unibox, Bassbox etc only model the low end response of the driver but have no bearing whatsoever on the actual frequency response above say 100 Hz.