My InDIYana 2020 build (if I can go)

dynamo

I made some sawdust toward the 2020 project providing I can go. If not, we’ll at least I used up some drivers! My initial plans for the quad of peerless p830869 woofers was an 8” mtm. This theme got me thinking to keeping that idea but going with an additional rear firing tweeter, but I have a quad of TC9s that I never can settle on a project for, so I thought I’d use them here.

The plan is a pair of the peerless 8 inchers per side in a 2ft3 vented cab, topped with an open baffle dipole mid mtm using the TC9s, with a hivi rt1.3 in the middle. I have all the drivers and started throwing together the cabs today.

The cabs are pretty budget oriented, using menards 3/4” particle board for the sides and back, and left over MDF for the baffles.

(sorry for the out of order pics..)

dynamo

I got one cabinet mostly assembled. I still need to paint the baffles, add some more bracing, and add the port and some feet. I plan to bottom port it and have feet raising it about four inches.

For now I threw the drivers in so I can take measurements and work on the initial crossover. The cab will be sealed for this part but I should still be able to get a handle on bsc.

dynamo

dynamo

Got some measurements in to set the offsets. The OB mids appear to measure even flatter than the sim showed so I’m happy about that. I brought the upper baffle up to be flush with the woofer baffle for determining offsets. I plan to push it back to zero the offset between the mids and woofers once I have those numbers. 

PWRRYD

Looks great!  Have you run any sims yet?  How does the sensitivity of two 830869 in parallel compare to a pair of TC9FD open baffle in parallel?

Wolf

Nice! Keep it up...

dynamo

PWRRYD said:

Looks great!  Have you run any sims yet?  How does the sensitivity of two 830869 in parallel compare to a pair of TC9FD open baffle in parallel?

Thanks! I have, and it will be close. I plan on needing a higher dcr woofer coil and utilizing a little band pass gain on the mids as well. With these I should be able to get the mids to keep up. I’m fortunate that the TC9s appear to measure a little more sensitive than they spec. 

squamishdroc

Looking good! I have to ask - what is under the car cover?

hifiside

squamishdroc said:

Looking good! I have to ask - what is under the car cover?

Crager wheels?

PWRRYD

Cragar S/S!

dynamo

squamishdroc said:

Looking good! I have to ask - what is under the car cover?

Thanks!

This: https://diy.midwestaudio.club/discussion/716/68-camaro-install
  

squamishdroc

dynamo said:

squamishdroc said:

Looking good! I have to ask - what is under the car cover?

Thanks!

This: https://diy.midwestaudio.club/discussion/716/68-camaro-install
  

Sweet ride!

hifiside

Didn’t you build some woofer for this project? Or was that someone else.

dynamo

I did, they are sitting on the floor in the background two pics up along with a diy sub. Those are actually planned to be the bottom of a four-way for the over $200 class at MWAF, along with a Dayton PM220, AE TD6M, and the Morel supreme tweeters I took home from there last year. We will see if it works out. I can’t always get my three-ways to work out, so four will be a struggle for sure! 

This is an easier project for an earlier event so I figure I’d tackle this first.

dynamo

Also, I would have considered building my own for this but on top of already having the peerless, I know Ben’s rules talk about currently available drivers and I wasn’t sure if a roll your own driver would violate that.

I wouldn’t want to use those that I already made much above 100 hz or so either as I did nothing to combat inductance and those are 2”, four layer, long, 8 ohm coils, which all made for massive inductance - around 5mh.

From some prelim sims I plan to cross this project  around 600 hz. I’d have to build a new set for these and probably wind my own voice coils to get more of a woofer than a sub.

Ive found that playing around with driver building really is teaching me a lot about the different factors that play into ts parameters and the comprises that need to be made just like in enclosure design, etc. 

Wolf

If you make your own driver, I would have you include the cost of the parts to make said driver. Everyone else can buy those same parts too, right? Then that applies.

dynamo

Cool, good to know. If these peerless end up being too sensitive for the design maybe I’ll roll my own!

PWRRYD

I don't want to be a Debbie-Downer-Dude, but my experience with those 830-869 woofers and those TC9FD drivers makes me think you might have a sensitivity mismatch issue with a passive crossover.  I could be wrong of course.

dynamo

PWRRYD said:

I don't want to be a Debbie-Downer-Dude, but my experience with those 830-869 woofers and those TC9FD drivers makes me think you might have a sensitivity mismatch issue with a passive crossover.  I could be wrong of course.

You definitely could be right and I appreciate your experience with both the drivers. I made it work before I built the boxes when modeling with traces of factory graphs just to get an idea. Hopefully tonight I can sit down and see if it’s going to work with real life measurements. Worst case scenario if it doesn’t work out I will probably just swap to different 8” drivers for the woofers, whether it be DIY or commercial. I still would like to do an 8 inch MTM with those peerless woofers so they have another home if they’re too sensitive for this application. I’ll let you know and thanks for the insight. The other nice thing is these boxes are made out of particleboard shelving from Menards so if I have to scrap them and go entirely different way I’m not really out much.

dynamo

It’s going to take more listening for sure, but so far the woofers don’t seem to overpower the mids at all, so it might work out.

joeybutts

dynamo said:

You definitely could be right and I appreciate your experience with both the drivers. I made it work before I built the boxes when modeling with traces of factory graphs just to get an idea. Hopefully tonight I can sit down and see if it’s going to work with real life measurements. Worst case scenario if it doesn’t work out I will probably just swap to different 8” drivers for the woofers, whether it be DIY or commercial. I still would like to do an 8 inch MTM with those peerless woofers so they have another home if they’re too sensitive for this application. I’ll let you know and thanks for the insight. The other nice thing is these boxes are made out of particleboard shelving from Menards so if I have to scrap them and go entirely different way I’m not really out much.

Project looks great and gives me an out with my 830869's.  Why the severe offset in the X-axis with the MTM in this design?  

I've been trying to find projects that use 830869's and an MTM with them would be awesome.  

PWRRYD

dynamo said:

It’s going to take more listening for sure, but so far the woofers don’t seem to overpower the mids at all, so it might work out.

Excellent!  I don't mind being wrong 

Now I need to get going on my InDIYana theme build.

dynamo

We will see, I can’t get it voiced right at all yet. I may need to go to steeper slopes on the tweeter and woofer and subsequently lose the mid gain (that I need) from the overlap. Time will tell I guess.

4thtry

  Cool project!!   Will these be the Zoinkers?      Or will that be a different project?

dynamo

These are the zoinkers I suppose providing you don’t want the name since I offered it to you, lol

4thtry

Cool ! 

dynamo

So I am still working on trying to get these to sound right.. 

I have really bad floor bounce on the woofers at 250hz or so. It is the same at one meter or two. What do you guys do with it? Is there anything? It’s just such a massive suck out in the midbass region.

Here is a pic of the measurement and with filter. Ignore the mountain below 100hz, it was measured at 1m in room with no splicing. The graph is both woofers measured together.

tajanes

fyi
On my open backs I’m running two 12in Ws with the top crossing to the mid and the lower as a ½ way (big coil).  This may ? reduce the issue- a bit counterintuitive, but separating the drivers freq a bit may be worth a try?  (assuming you don’t want to go active) 

jhollander

I usually ignore it.  You could move the woofers higher on a short stand. Dave DalFarra (DDF on PETT) has a mic height program that you can play with that predicts the notch frequency. You can also move your mic up and down to see what listening angle the dip becomes livable to predict a stand height.

dynamo

Thanks guys. John I am kind of stuck on driver height unless I cut the baffle off, so for now I will take your advice of ignoring it. Tajanes I like the idea of going with a1/2 way setup here but Ben’s rules limit me to a 3-way, so 3.5 would be a no go, but thanks.

jhollander

With my coax build I had a short tower that sounded great unless there was a table in front of the speaker. I think the height also hurt me at MWAF, along with the brown veneer w/ black grill.  If the picture above is the final version height you might consider a temp stand at the event.