My Home stereo makeover

I've had a pair of Digital Audio tower speakers for a bit now. I like the way they sound in the midrange on up, but the midbass is very boomy and overwhelming, and the lows are none existant.

I'm going keep the drivers and build a pair of new towers at 40" tall and adding a powered subwoofer. Since I don't have any perameters for these speakers, I designed a pair of tapered tranmission lines because they are rather forgiving. I want to have alot better transient reponse than before.

Today I ordered this amplifier to power what is now going to be a single :DD:510. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-804

I also ordered some binding posts, and foam dampening. I have not decided on an enclosure alingment yet for the 510, but I have 6 sheets of 2'x4' MDF waitin for me. Now on to pics.

I'm currently having issues with my modem, so pics are going to have to wait.

Onto pics. I should have mentioned the crossovers that were in the towers are going to be used for the time being also.

Out with the old towers.




The DD510


The new towers

Is this why you called me, then wouldn't call me back?

Should perform fairly well. Play around with polyfill in the t-lines, but I'm sure you already knew that.

Didn't take long for the 510! Not long at all! If the price was right and they had one in stock, i'd pick up a 1508 or two. Don't know why... just cause. Like the 3512F motor.

Ha, It must have been Vivien playing with our phone, lol I never ment to call you today. She plays the angry birds app and sometimes gets lost in the rest of the phone.

Indeed the price was right on the 510 It had a scuff on it, so you know... 70% off right there I'm not sure steve would like it getting out how much he gave it to me for though. I was going to go with two 510's, but I dont want to pay for the power to run both

The area right behind and above the drivers is getting a nice egg crate foam down to the bottom of the taper panel. I might play with polyfill, but I'm not expecting to have to use it. I've been out cutting the wood down since 10pm tonight. Got a box to do for a guy at my school too.

Takeing shape a bit

More progress tonight.

Drivers in yet?!?!

Not yet. As soon as I was done sanding, it was off to box #3 for he Alpine type R 12. I probably won't have the drivers in until the end of this week.

So I got them fired up and painted, here are my thoughts. Overall results were much better than expected. I don't think I'll have to put much work into tweaking them at all.

Note: I'm going by ear here. I played a bunch of songs over about an hour period with both speaker cramped in the corner of my small room.

*Midbass is cleaned up, but seems to still have an anoying slight peak near 80hz. I'm now thinking this is a driver issue, that was earlier compounded by the trash heaps they were in. I know it is not a room placement issue, as I listend and played with them before in a couple different rooms.

Start of the line = 1.27x SD
End of the line tapered to .24 X SD
Line length = 82" - 1/4 wave of about 41hz.

* Output on the bottom end = better than expected, play well down to 30hz in my small room, then they drop off a cliff.

* I took a guess as to where the fs and Qts of the drivers might be, and tried to play it safe. It seems the common trend with good results is tune a bit below fs for a higher Qts (.4 and up) driver, and lower than fs for a lower QTS driver, (below .4). This has to do with controlling the rolloff combined with the desired impedance curve a TL system should have. Thats a tangent for later.

* I think I may have overshot the tuning more than expected with the taper, the tuning came out much lower than I thought it would, but I think it works really well. I will play with some dampening and try to null the peak at 80hz.

* I can't really comment on the midrange until I get some dampening in them, but overall I'm very impressed, considering I took a stab in the dark approach. I feel it payed off this time.

I'll get pics up in the morning. Its 3:30ish and I dont want to incur Ashlees wrath by snaping photos in a dark room while she sleeps.

It's 6:30 now...pixors?

Naw. The way things have gone today, I wont have pics up until I get out of school at 10 tonight.

Here we go:


And a new toy to play with and do some testing? A and C weighting with peak hold.

I guess I should update this. It's been rather slow going though. Decided to use my pair of RE SR-10's wire series/parallel to 4 ohms.


Transfer function


SPL w/100 watts


Group Delay

And? How does it sound?

The subwoofer sounds great! Plays as flat as the graph suggests, and certainly gets loud. That amp can throw those subs with no effort. I still need to get the receiver and everything wired up. I still have yet to play it with everything hooked up.