Stealth Force One " Inner Sanctum"

Analogkid455

The room in Indiana really seem to reinforce the lowend quite a bit which made my speakers sound like they had a huge subwoofer in them. In my 20 X 22 foot room, they sound a lot more balanced. I wouldn't think there would be that big of a difference.
Anyway, they use the RST28F tweeter crossed at 1600 hz 2nd order Butterworth, the DSA175 crossing around 220 hz, ( I think that is were it ended up) and two DC250-8 in a push pull isobaric with two DA270 PR. Tuned to 31 hz.
I will have to dig up the measurements off my PC but it measured within 2 db from around 400 hz to 16khz I was the first to lose to Nick's entry. Glad he won.

Analogkid455

kenrhodes

These are really cool speakers and I bet they are fun to rock out with.

Analogkid455

@kenrhodes said:
These are really cool speakers and I bet they are fun to rock out with.

Yes, I mostly listen to Rock and Metal but I also listen to Blues, Jazz, funk and sometimes even Classical.
SPL wise, they model 111dB a pair at XMAX with a 100 watts per side. Not ground breaking but plenty loud for most people. Sitting 12 ft away, 85dB at the listening position, the drivers are barely moving. At 3 feet away that equates to 97dB. The bump at 50 hz is caused by the room I measured them in. Being tunes to 31 hz, I don't know why they don't go in the 20s in room. May have to investigate why. I verified the tuning with DATS. I rushed to get tjem finished in time and may tweak the crossover some on the bottom end. Also might do some other stuff that I wanted to try.
Overall, I am happy with them. They ARE fun to listen to. You can crank them with Metal music and they never get fatiguing.

a4eaudio

They sounded nice!
The list of people who have been knocked out by Nick's entries over the years is pretty long.

DanP

I thought these sounded really good and was one of the few people that voted for this one over Nick's eventual winner. As it turns out, I changed seats halfway through the contest and the bass issue I was hearing in Nick's entry disappeared, but that doesn't take away from this design that is very well balanced and really cool looking.

ugly_woofer

I liked these, they were well balanced. Nicely done Erik.

Wolf

I liked these too.

6thplanet

I also voted for these. From my seat I liked the bass and the mid-range was a bit cleaner sounding. Nice work dude!

Analogkid455

Thank you all. First time doing anything like this. It's good to know other DIYers enjoy what I did.

Analogkid455

@DanP said:
I thought these sounded really good and was one of the few people that voted for this one over Nick's eventual winner. As it turns out, I changed seats halfway through the contest and the bass issue I was hearing in Nick's entry disappeared, but that doesn't take away from this design that is very well balanced and really cool looking.

Thanks Dan. I will be working on what we talked about with the new waveguide tweeter.

Analogkid455

Never got to hear these for more than an hour after I was done with them. Put them out in the big room with my Yamaha AVR. When I got home, listened to them for a while and it seemed like something just wasn't right. Pulled out my Nakamichi Stasis amp and all the sudden, it came alive. Huge dynamics and the soundstage opened up. Amps DO make a difference. When tuning the crossover I was using one of my Parasound amps.

Analogkid455

So, I finally got some time to sit down with these things and no wonder people liked the bass. I think the PR's finally broke in and they have to much bass for my taste, and I love boosted bass. Tomorrow I am off work so I will remeasure in the big room and see what I have. Will for sure get rid of some resistance on the tweet and mid.
Like I said before, I barely got these things finished in time. I was certainly worried about the PRs not being broken in enough. They have huge output now, lol!

Analogkid455

BTW, that might explain why I wasn't getting good response down into the 30s and even the 20s, in room. Although the tuning was verified at 31 hz. Hell if I know.

DrewsBrews

That Friday they seemed realy satisfyingly punchy, but Saturday they seemed a little more bloated in the bass. I honestly figured it was just due to me being in a different spot in the room.

Wolf

Pretty sure I agree with this assessment.

Analogkid455

As suspected, 7 db bump at 60 hz. Anyone know what would cause this? Again, verified tuning to be 31 hz. In room response now gets down to 21 hz -3 db. Those 44 dollars woofers do pretty good.

DrewsBrews

I plugged factory woofer TS values into WinISD and guessed the internal box volume is somewhere around 1.5-1.7cf.

Adjusting mass on the PRs to your tune (~35g) I do get a hump around 40hz.. but only between 1.5-2db.

Maybe since the woofer/s are at the bottom you are getting some transmission line effect due to the height of the cabinet?

kenrhodes

You effectively corner-loaded the drivers against the floor. This should give you a good boost but should cover most of the output frequency of the woofer.
Accurately measuring down to 60hz is pretty complicated. You may need to try moving the speakers around to see if this peek is the room or the speakers.
How did you verify the 31hz tuning?

Wolf

How did you verify the 31hz tuning?

I would bet by impedance measurement.

Analogkid455

They are working in 1.3 cubic feet and I measured tuning with DATS. The peak is there close mic ( 1 inch) and in room micing.