Monkey see, monkey do... two RL-P18s for me too!

**Bradley** · **11-11-07, 02:34 PM**

How do you know it's the amp that is rolling off? At least when you model it, the output from the sub drops like a rock at 10 Hz while cone excursion soars.

**brucek** · **11-11-07, 03:19 PM**

Yeah, I guess you'd have to do a response of the amp itself to determine that.

**Bradley** · **11-11-07, 03:29 PM**

OK, just can't stop playing with REW.

I stood the sub up and moved it into the corner of the room to see how that would affect FR. Previous measurements were with the sub "horiztonal" and beneath the screen (as pictured earlier in this thread).

Moving it into the corner made a big difference. The graph below was done with the mic in the exact same position as the first graph I did with the big dip at 58.5 Hz, but there is no trace of that dip now.

Also note I changed the scale to 5 dB increments instead of 10.

**Bradley** · **11-11-07, 04:06 PM**

Almost ready to give the Epik Conquest a run for its money.

**brucek** · **11-11-07, 04:15 PM**

Quote:

Also note I changed the scale to 5 dB increments instead of 10

Usually best to display about 60dB swing in the vertical scale.

The standard we usually use is 45dB to 105dBSPL on the vertical axis...... This places the 75dB target at center scale.

brucek

**Bradley** · **11-11-07, 04:22 PM**

Quote:

brucek wrote:

Usually best to display about 60dB swing in the vertical scale.

The standard we usually use is 45dB to 105dBSPL on the vertical axis...... This places the 75dB target at center scale.

OK, thanks. I've just been messing around and having fun with it so far but I do remember reading somewhere that Dolby Labs and/or THX recommends a 75 dB target. I guess if I want anyone to take me seriously, I better get with the program.

**SteveCallas** · **11-11-07, 04:31 PM**

Thanks for the close mic measurement Bradley - looks like a 5-5.5db rolloff to 100hz.

The Conquest won't be nearly as linear into the infrasonic range as your beast. Considering you'll have built two of them for roughly the cost of one Conquest, you'll have it beat by plenty in all regards

**Ilkka** · **11-11-07, 05:43 PM**

Quote:

Bradley wrote:

Almost ready to give the Epik Conquest a run for its money.

The Conquest was measured outdoors.

**Bradley** · **11-11-07, 05:47 PM**

I wasn't totally serious, but since you mentioned it... who measured it outdoors? Link?

**Ilkka** · **11-11-07, 05:51 PM**

Quote:

Bradley wrote:

I wasn't totally serious, but since you mentioned it... who measured it outdoors? Link?

The Epik thread over at AVS has some measurements. Not very thorough though...

**Bradley** · **11-11-07, 05:58 PM**

Oh, that deal where he got one quick sweep in as it was starting to rain? I'll have to go take another look at that. Did you see the in-room test Tom Nousaine did on the Conquest?

Also, do you find that subs with the port on the rear or side of the cabinet don't do (as well as they might be able to otherwise) in an outdoor ground plane measurements?

**Ilkka** · **11-11-07, 06:04 PM**

Quote:

Bradley wrote:

Oh, that deal where he got one quick sweep in as it was starting to rain? I'll have to go take another look at that.

Yes.

Quote:

Did you see the in-room test Tom Nousaine did on the Conquest?

I did. But unfortunately they are only comparable to other subs measured by TN.

Quote:

Also, do you find that subs with the port on the rear or side of the cabinet don't do (as well as they might be able to otherwise) in an outdoor ground plane measurements?

I always try to place/orientate the subwoofer so that all the radiating elements (woofer, port etc.) are at 2 meter distance from the microphone. Of course this isn't always possible but the difference is very small.

**Bradley** · **11-11-07, 06:34 PM**

Well, that outdoors graph posted over on AVS shows the Conquest holding around 115-117 dB from 15 Hz on up. Pretty impressive if that is an accurate 2m ground plane measurement. I don't really care if I "beat" the Conquest. It's just fun to compare, since that's the closest commerical equivalent to what I've built. Like Steve said, I will have built two subs for the price of the Conquest (*if* you don't count the cost of all the ' tools I bought) and it's been an interesting "adventure" so far to say the least!

**thxgoon** · **11-26-07, 12:55 AM**

Hey any updates? Did you get the second sub built? How are you liking things so far?

**Bradley** · **11-26-07, 01:06 AM**

Yes... made some progress on the second subwoofer box over the weekend and posted new pics over on AVS.

Pretty happy with the first subwoofer.

Even with one sub and 650 watts, pretty much EVERYTHING is rattling in my basement HT room. That drop ceiling has GOT to go!

**Bradley** · **11-26-07, 01:08 AM**

Kinda feels like deja vu here.

Subwoofer #2 construction pics...

Finished installing the port tube and the side panel with the port outlet.

**Bradley** · **11-26-07, 01:09 AM**

Well... I'm not sure I'm doing all that much better of a job on subwoofer #2, but no major problems have cropped up so I guess it's all good.

Bondo!

Lots and lots of hand sanding, then shot it with some paint just to make it look uniform (and make myself feel better).

All four sides on... front, back, left, right.

The last of the braces... **** port tube! Totally in the way.

Other end was easier.

Looking like a bona fide "box" now.

**thxgoon** · **11-26-07, 02:05 AM**

Looks good! Can't wait to hear your listening impressions with two of those beasts

**Owen Bartley** · **11-26-07, 08:18 PM**

I'm trying... I'm really trying... and I just can't imagine what these beasts would sound like. This must be a totally new realm of bass. I can't wait to hear your impression of these subs, and find out what they do to your house. I just watched Transformers with my Tempest and new Buttkickers and I got a little scared at points. I bet you'll scare the neighbors!

**Avus_M3** · **11-30-07, 04:52 PM**

I didn't know you had a thread over here as well? Looking forward to what you have to say about going from 1 to 2 of these beast!

**Bradley** · **12-02-07, 08:28 PM**

Hey, Dave. I just got back from a weekend trip to Southern California. I'm pretty tired right now but I might do a little more work on the 2nd sub tonight. It's only a couple hours of work away from being operational (minus the paint). Should have it wrapped up some time this week!

**Scott S** · **12-03-07, 04:49 PM**

Cool! Can't wait, Bradley. I have very much been interested in seeing both of your subs finished. Im sure you have been having plenty of fun with your first but when you fire up that second, heh... you'll be glad you got it.

Good house shaking fun.

Will you be pairing them together in the corner or were you going to have the second sub in the opposite corner? Not sure if I asked that already.

**atledreier** · **02-11-08, 03:21 PM**

So how did it go? I'm dying to read what you think, and see some measurements and pictures!

**Bradley** · **02-11-08, 04:31 PM**

Sorry I haven't updated this thread in a while. The 2nd sub was finished a while back. Here are some pictures and a graph of in-room response.

The sub with the paint around the driver is unit #2.

Here's how they are oriented presently.

And here's a measurement I did just for fun and "bragging rights". This is a corrected measurement using the RS Digital SPL meter placed on the HT recliner arm in the middle of the room, which is well over 2 meters distance from each sub.

118 dB at 12.5 Hz. Not too shabby, eh?

**atledreier** · **02-12-08, 12:31 AM**

Duuuude...

Totally awesome! Love it! How's your amp liking them?

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