DIY RE-Cabinet

[IPunchCholla]

I’m re-cabineting my Pioneer drivers. They are from a pair of CSM-555s I bought way back in the 90’s. The old cabinets have gotten pretty beat up over the years and they were no great furniture objects to start with. In fact they were dirt cheap in terms of construction. Less than 1/2” cheap MDF. No internal bracing. No damping. POS crossover. Plastic-y drivers. No gaskets on the drivers.

Weirdly, I think they sound pretty good. So about a year ago when I got into audio, I decided to measure them in room. And the performance wasn’t horrible. THD was around 5% for everything above 100hz (I think, I will post the original measurements later), and noise was below the sound floor of the room. But there were resonances and a few valleys and humps.

So I decided to build new crossovers. I converted an old sound card to make impedence measurements of the drivers and used the dual weight method to reconstruct the Small/Thiele parameters. I modeled numerous crossovers in SpeakerSim. Settled on one and built a pair. This got me a smoother response giving me about 5dB more headroom for my automatic room correction software. But there were still some resonances.

So I thought I would try building new cabinets for them as it would be a good way to learn CAD/CAM and my CNC machine (which I needed to do for other art projects I am working on). A year on now and I am getting the first cabinet prototype (after modeling more than 5 fully developed cabinets) pretty near the point of testing so I thought I would start this thread.

I’m using 3/4 MDF for everything except the baffles which are 1.5” at their thickest. Along with internal bracing, they will be damped and the drivers will be gasketed. Without the plans feet. They are 44” x 8” x 15” and the top, bottom, and sides are all angled in at three degrees. I’m planning on painting them dark gray. Pics below and more posts to come.

 

[kiwifi]

Nice work!

 

[tomtoo]

Very nice look!

 

[IPunchCholla]

Old and new crossovers:

 

[dtaylo1066]

Nice job on the MDF! After all that work, I'd be tempted to put other drivers in those babies than Pioneer!

Are those a 3-way with side firing woofer?

Surely there are some higher quality mid-basses out there whose parameters would fit the cubic foot volume of your boxes.

Just a thought as you go deeper into DIY.

 

[IPunchCholla]

Nice job on the MDF! After all that work, I'd be tempted to put other drivers in those babies than Pioneer!

Are those a 3-way with side firing woofer?

Surely there are some higher quality mid-basses out there whose parameters would fit the cubic foot volume of your boxes.

Just a thought as you go deeper into DIY.

Thanks! It’s really a 2.5-ish way with a side firing woofer. The original crossover had no filters on the 12” woofer. I added a pretty high low pass to attempt to reduce distortion at the upper end of the range. The lower front is a port. Looks big but that is the funnel shape. The tube is the same diameter as the original port. I eventually plan to either adapt these cabinets or build new ones around better drivers. Probably going the active route (bookshelves and multiple subs). This is mostly for me playing around seeing how all the parts fit together, learning as I go.

 

[dtaylo1066]

There are many great DIY speaker building web sites and forums. A sense an addiction forming. Have fun!

 

[IPunchCholla]

Got the right cabinet rough fit together (back on but not secured, drivers installed but no gaskets, acoustic foam damping installed, but wires not fully routed... Oh yeah, port is still 11 inches long which means it is tuned to about 17Hz. Did a quick measurement. Darker green is all the same gear but old cabinet. Lighter green is new cabinet. Both located in the same place, but obviously the drivers are nor anywhere close to where they were. Woofer is 8" lower and back a few inches. Tweeter and midrange are elevated 6 to 8" and angled up.

 

[kemmler3D]

Cabinets look dope, you clearly know your way around a CNC router. As for the drivers... 5% THD is not atrocious, but is nothing to write home about. Given your cabinet making skills, I second the motion to put something together with higher-end drivers if you aren't totally sick of speaker-building after this project.

DIYAudio is a really good forum to check out, the membership there would definitely get a kick out of what you're able to do with a bit of MDF.

For an in-room measurement it doesn't look half bad either, but the hump between 100 and 200 and the dip between 2-8khz is a bit concerning.

 

[IPunchCholla]

Cabinets look dope, you clearly know your way around a CNC router. As for the drivers... 5% THD is not atrocious, but is nothing to write home about. Given your cabinet making skills, I second the motion to put something together with higher-end drivers if you aren't totally sick of speaker-building after this project.

DIYAudio is a really good forum to check out, the membership there would definitely get a kick out of what you're able to do with a bit of MDF.

For an in-room measurement it doesn't look half bad either, but the hump between 100 and 200 and the dip between 2-8khz is a bit concerning.

I'll check them out! Yeah, I will probably go to better drivers eventually, though part of doing this is being curious about what I can actually hear. Those bumps look pretty rough, but honestly without being able to quick A/B them I'm not sure I can actually hear it. Particularly after apply ARC software. So the cost/benefit of the drivers will really have to be there.

The 5% figure was an overall average. for much of the spectrum they are below 1%, but distortion peaks up a bit in the subs and high frequency.

 

[valerianf]

What worry me is that the low frequencies below 100hz are down on the light green trace.
May be you have a problem with the BR tuning.

 

[IPunchCholla]

What worry me is that the low frequencies below 100hz are down on the light green trace.
May be you have a problem with the BR tuning.

The tuning for that plot was at 17hz (since it was a test fit. The tuning for the final assembly will be around 35hz.

 

[IPunchCholla]

Finally getting some time to finish these. Hopefully done in the next couple of days!

 

[IPunchCholla]

Finishing took way longer and didn’t come out half as well as I hoped, but they’re done-ish (still need to tune the port)! Sound the same.

 

[IPunchCholla]

 

[Doodski]

Hehe. I am still amazed at what you have done with this project for your first time. You studied the electronics, designed a cabinet, CNC routered the cabinets with some great looking chamfers at the front and painted them a nice neutral color that is up to date. You are a very effective and fast learner!

 

[IPunchCholla]

Hehe. I am still amazed at what you have done with this project for your first time. You studied the electronics, designed a cabinet, CNC routered the cabinets with some great looking chamfers at the front and painted them a nice neutral color that is up to date. You are a very effective and fast learner!

Thanks its been fun (and an interesting learning curve)! I definitely learned a bunch along the way, and have no intention of stopping. Up next is finishing up the control board for an IcePower based amp I’m hoping to assemble.Got the parts in from DigiKey to make the prototype. If that works as per expected given my simulations, I’ll probably commit and build the amp.

Next speaker will definitely be bookshelf size and actives!

 

[Doodski]

Thanks its been fun (and an interesting learning curve)! I definitely learned a bunch along the way, and have no intention of stopping. Up next is finishing up the control board for an IcePower based amp I’m hoping to assemble.Got the parts in from DigiKey to make the prototype. If that works as per expected given my simulations, I’ll probably commit and build the amp.

Next speaker will definitely be bookshelf size and actives!

I wish I had your brains! You're like a excelling athlete but instead a academic at the top of the heap compared to the average intelligence. I guess that's why you are where you are professionally.

 

[JRS]

Thanks its been fun (and an interesting learning curve)! I definitely learned a bunch along the way, and have no intention of stopping. Up next is finishing up the control board for an IcePower based amp I’m hoping to assemble.Got the parts in from DigiKey to make the prototype. If that works as per expected given my simulations, I’ll probably commit and build the amp.

Next speaker will definitely be bookshelf size and actives!

Active studio monitors are where its at in my book. Everyone says one needs 2 subwoofers independently located anyway, and so not a real need for the real low stuff and towers can become monitors! In my book--that's maybe up to 2 x 1.5' x 1' but typically smaller in one or more dimensions leaving a net volume in the 1 to 1.75 cu ft range which can accommodate many outstanding woofers in the 8 to 10" range (or two 6.5" or 7") with a reasonable sealed or higher order cabinet (PR's instead of vents is becoming more common for good reason).

The argument against monitors is they take as much floor space which while technically true, IMO an open stand supporting a monitor feels so much less imposing architecturally. It's a great deal of fun doing actives given the awesome drivers available these days. Couple of indispensable resources are Parts Express (great forum there, smaller, civil audience) and Meniscus Audio. which carries a lot of nice kits that leave the cabinets to you. In some of my actives I have passive XO's installed just in case I want to gift them or move to another room where I may not have 4 to 6 channels of amplification handy. That's what makes the kits a pretty good deal--pay for the drivers and get the xo components for close to free--maybe not the fanciest of capacitors, but good enough.

Madisound is another well known resource, but I have never purchased there--they carry all the SEAS lines and have a deep stock of Scan Speak and the kits for some very expensive SOTA projects including the well known Orion loudspeakers designed by Linkwitz. (I'm more of an SB Acoustics fan personally as ones dollar goes further for comparable quality). And of course there is Troels Graveson who has an amazing web site and plans for 50 loudspeakers with some detailed plans and pics to accompany. Just reading the descriptions of his thought processes in creating these projects is an education.

It's a great hobby. Started building in 2001 and never looked back--this after enjoying 15 years of owning some outstanding commercial systems (Dunlavy, Thiel, Infinity IRS, ets). My all time bang for the buck faves were an MTM (Usher midbass + SBA tweeter) that checked all the boxes and were 1.25 cu ft I believe--stolen sadly.

 

[IPunchCholla]

Active studio monitors are where its at in my book. Everyone says one needs 2 subwoofers independently located anyway, and so not a real need for the real low stuff and towers can become monitors! In my book--that's maybe up to 2 x 1.5' x 1' but typically smaller in one or more dimensions leaving a net volume in the 1 to 1.75 cu ft range which can accommodate many outstanding woofers in the 8 to 10" range (or two 6.5" or 7") with a reasonable sealed or higher order cabinet (PR's instead of vents is becoming more common for good reason).

The argument against monitors is they take as much floor space which while technically true, IMO an open stand supporting a monitor feels so much less imposing architecturally. It's a great deal of fun doing actives given the awesome drivers available these days. Couple of indispensable resources are Parts Express (great forum there, smaller, civil audience) and Meniscus Audio. which carries a lot of nice kits that leave the cabinets to you. In some of my actives I have passive XO's installed just in case I want to gift them or move to another room where I may not have 4 to 6 channels of amplification handy. That's what makes the kits a pretty good deal--pay for the drivers and get the xo components for close to free--maybe not the fanciest of capacitors, but good enough.

Madisound is another well known resource, but I have never purchased there--they carry all the SEAS lines and have a deep stock of Scan Speak and the kits for some very expensive SOTA projects including the well known Orion loudspeakers designed by Linkwitz. (I'm more of an SB Acoustics fan personally as ones dollar goes further for comparable quality). And of course there is Troels Graveson who has an amazing web site and plans for 50 loudspeakers with some detailed plans and pics to accompany. Just reading the descriptions of his thought processes in creating these projects is an education.

It's a great hobby. Started building in 2001 and never looked back--this after enjoying 15 years of owning some outstanding commercial systems (Dunlavy, Thiel, Infinity IRS, ets). My all time bang for the buck faves were an MTM (Usher midbass + SBA tweeter) that checked all the boxes and were 1.25 cu ft I believe--stolen sadly.

Thank you so much for all the suggested resources!