Alternate AV15 sub design (1 Viewer)

[Woodpin]

I thought I was all set to begin construction on my two AV15 powered subs for my home theater/music room last spring after purchasing them from John @ AE. I had decided on a sealed design of 4.33 cuft with a Behringer Feedback Destroyer for EQ and 500 watt Bash plate amps for each sub to get me down to or near 20 hz. I emailed John with my plan for his approval and he asked if I had considered dual 18" passives to bring me down to 18 hz without EQ, be as tight and accurate, much more efficient, and all this improvement in a two foot cube. Well, I was all about that since size is an issue, and promptly ordered four of his 18" 1600g passives with a projected delivery of two months to give time for his new facility and line development.

Well, It's now been 10 months, the sight is dormant, my order still shows "pending", and emails are answered with a generic reply on autopilot. I know from reading the posts that he's had his share of setbacks and health problems, but I'm not getting any younger either, and really miss my music. Unless someone here has some encouraging late breaking news about AE or Stryke's new opening real soon, I need to re-consider the sealed with a BFD, or a Linkwitz Transform circuit as John also suggested.

I tried to download the spreadsheet for the Linkwitz Tranform from one of John's emails, but my computer doesnt have Excel and I am reluctant to spend the $70 for it.

Anybody got four AE or Stryke 18" 1600g passives for sale? If not, another source for the Linkwitz Transform formula or help with it would be appreciated. I have a copy of the schematic and even a source for printed circuit boards, but no way to calculate the values yet. Maybe someone here has already done this for the AV15 in a 4.33 F^3 box, 20 hz (or less), .707 alignment. The 4.33 came from WinISD Pro Alpha. I assume it's accurate, but you know what they say about "assume"! I've noticed a few unsettling kwirks with the software. Would the BFD do a better job alone since it's selectable and continuously variable to compensate for room gain?

My system: Marantz SR5400 A/V receiver used mainly for routing (pre-out) except rears, two SWTPC Tigersaurus monoblocks (270wrms @.01 THD) powering mains, upgraded Ohm F's for mains, Ohm 3's for rears, and a 6" MTM planned for center, although with the receiver fronts set to "large" the Ohm's create the center very well because of their unique imaging.

Any input will be greatly appreciated. Need bass! I have to really attenuate the bass to protect my F's when watching action videos. They just won't take it, and one day I'm going to forget! They also have trouble hitting low C on big pipe organ recordings which is around 20 hz..

Thanks, Woody

 

[Robert_J]

There is no good news with John and AE Speakers. His partner from last summer, Deon Bearden, moved to San Diego to work with TC Sounds. But that may be short lived as it is rumored he has moved to San Antonio to go back to school and be closer to his fiance.

If you are planning on using PE BASH 500W amps, you will never get to the 20hz response that you want. It has been determined that they ship with the sub-sonic filter set around 30hz. You need to use the included documentation to swap some resistors. A better alternative would the the BASH amp for O Audio. It has selectable filters.

Good news is that TC Sounds is releasing some less expensive PR's. Even better, they will have aluminum cones like your AV15.

And there are a few quirks with WinISD. A better alternative is Unibox but it requires Excel just like the LT spreadsheet.

-Robert

 

[Woodpin]

Thanks for the info, Robert. I did find it a bit hard to swallow at the $500 plus shipping for the AE passives since that's considerably more than I paid for the drivers. So, I guess I should remain patient a little longer, and stick with the passive design.

I didn't know about the filter in the PE Bash 500 w amps, but I did purchase them at the same time as the AV15's. I'll have to decide wether to make the modifications or sell them and buy more substantial amps. The transformerless design concerned me, but I was assured that they would perform as well or better than amps with transformers. My Tigersaurus monoblocks have a flat bandwidth from 5 hz to 200 khz and have huge transformers, but I need them for my mains and really don't want to waste the high end on subs.

Woody

 

[Bob McElfresh]

HeyDaryl - I'm going to move your post to the DIY fourm. Your issues are a bit beyond the "Basics" fourm.

 

[Woodpin]

OK, Thanks, Bob. More eyes, more ideas!

Woody

 

[Robert_J]

I haven't done a resistor swap but I'm told it takes a couple of minutes if you have a good soldering iron.

If you can build a little bigger, try out this design - link. It's a little bigger than your sealed option but it should give you the output you want. If you can make the enclosure larger, you could tune lower by using elbows on the ports. Adjust the SSF on your plate amp to a few hz below the tuning frequency.

I'd still use a BFD to even out the room's response. But for the cheaper of the measuring options, you will need Excel. (get a cheap copy of Excel 2K) You use a disc with tones from 5hz to 200hz and measure each one with a Radio Shack SPL meter. You then manually adjust the BFD to even out the response and measure again. The faster, more expensive way calls for a PC, good sound card, good mic, MIDI cable and Room EQ Wizard (free). You measure response and adjust the BFD from the PC.

-Robert

 

[Woodpin]

Hey, Robert,

Checked out the link, and I know that design gives best bang for the buck, but, again, size is an issue. Thats why the passive is my preference, with sealed as alternate. But thanks for the suggestion.

Also checked out the TC Sounds site and saw that the passives are still expected but no time given. The price is a little higher than the ones I ordered from AE.

Woody

 

[Robert_J]

That's your only choice for PR's right now. TC will be releasing a new line of less expensive/lower performing PR's soon.

-Robert

 

[Woodpin]

I sent TC an email requesting specs and a time frame for availability a few days ago, but no response yet. As far as performance goes, I don't want to sacrifice quality and wish I had gone the extra mile. It's worth the extra $100 or so for the confidence of doing the job right and really enjoying the experience and the results.

Woody

 

[Robert_J]

You won't get a response from TC. It's better to sign up on their forum and post a question. Or call them. I did for a question and the girl that picked up the phone (I think it was Heather) had all of the answers.

-Robert

 

[Woodpin]

I'll do that, Thanks, Robert.

Woody

 

[Woodpin]

Hey, Robert,

Just ordered four 15" passives from TC Sounds. Also caved in and ordered two TC-2000 15" subs to go with them. Just couldn't stand the temptation after reading the positive feedback in the posts.

Anyone interested in two brand new AV15's? $325 for the pair plus ship.