Please review the site Rules, Terms of Service, and Privacy Policy at your convenience. Rules, TOS, Privacy
Get familiar with the reaction system: Introducing the Reaction System

Those Morel Integra Coaxials

edited August 13 in DIY

So I was lucky enough to win one of the pairs of Integra 424s. Very grateful to have the chance to mess with something that would normally be quite out of my price range. Not sure my skills would do them justice but I'll try (when I can get around to it). Figured I'd share their weirdness. Weird to me at least, like holding a piece of alien technology.

They list the effective piston area as 63cm2. Measuring inside surround to outside surround I get ~57.7cm2. If I measure outside to outside of the surround I get ~66.5cm2. However that includes everything inside that huge voice coil that isn't moving with the cone, which comes to about 21.5cm2. Is it normal to include non moving portions in effective piston area? The cone is just this little 5/8" wide sliver.

The felt is glued in. If not I'd already have taken a peek. Tweeter Fs indicates to me it is not an open vent, thankfully (basically matching the MDT 12). Some sort of vent for the mid cone voice coil gap? Or maybe a glue glob to fill the hole, and a sticker to cover it, would just be too lowbrow. ;)

They sell pre-fabbed car audio style crossovers for the Integra coaxial line. Looks like they cross them all at 2200hz 12db slope. On the factory response graph there is a ~5db peak centered right at 2200hz in the mid response that seems worrisome.

I'm still not too good about knowing what I'm looking at with regards to mid/tweeter specs. Tweeter xmax seems healthy enough. Though for the mid section 3mm xmax on what seems like the cone area of a 3" driver (if the tweeter/waveguide is subtracted). Would that normally handle being crossed to a woofer around, say 600-800hz?


  • Looking at the data sheet the low end response will probably be dictated by the baffle width. Using a woofer for the bottom of a 3 way this should make a really nice 3 way with excellent off axis responce. The woofer will essentially be filling in for your baffle step losses.
    A thin tower with a woofer(s) low against the floor might be magic.

  • edited August 13

    Yeah that was my thought. Lean into it's small size as an opportunity for a narrow baffle. I've got a case of Peerless 830855s (the 3.5" woofers). A 6" wide tower would be rather striking and bumps baffle step up to where hopefully this can safely reach.

  • edited August 13

    For optimal midrange clarity, I would suggest staying one or two octaves above the cones resonant frequency. Keep the cone travel down. These drivers might also make really nice satellites for a subwoofer/satellite combo.

  • I would think the Epique woofers you got would go great with these in a 3way.

  • Also, WinISD autocalculates the cone area (Sd) as 63.3 cm^2.

  • Congrats on scoring a pair of these! One of the best prizes on the table, imho. If you decide to build a narrow tower, consider building it with a removable/replacable baffle board. Then you can make extra baffles to experiment with different woofer to floor spacing distances. Putting a woofer right at the floor verses 12 to 17 inches above the floor can significantly affect your BSC and lower crossover design choices.

  • edited August 13

    I reread my post. I meant crossing to a woofer around 600-800hz. Probably looked like I meant the tweeter. Doh (fixed it)

    @Billet said:
    Also, WinISD autocalculates the cone area (Sd) as 63.3 cm^2.


    So I suppose it would probably fine with that crossover range.

  • edited August 24

    @Wolf said:
    I would think the Epique woofers you got would go great with these in a 3way.

    Yeah I entertained the idea for a minute. But I've got a second set of beastmode tweets that need a home too. hmm
    How is the midrange on the 5.5" Epiques?

  • According to the curves generated in Voice Coil, I would not use it as a 2way woofer. IIRC, it's good to 450 at best, and not higher. That is how I will be using my pair.

  • edited August 25

    The 3rd order peak I'm guessing?

    Sigh, well guess that concentrates all the "money drivers" into one build. That way if/when I fail it will be an epique fail :p Funny enough I think I've already come up with a name: Mellivora. The silvery grey cone made it come to mind. Google it and you'd understand. ;)

    Sofar, to get the most out of those woofers, seems either dual 7" epique PRs, or an integrated stand that incorporates the rather long port needed. The PRs are enticing to pack all that angst into the smallest package.

  • edited August 25

    Ooh I forgot about those SB racetrack PRs...

  • A single 7" Epique PR will work with the 5.5".

  • edited August 25

    Yep.. 6 liters a single PR gets nearly 50hz f3. 10 liters and two PRs dig down to almost 40hz. It is probably up to interpretation as far as which is better/more impressive. I could understand going wither way. The nice thing about the Epiques seems to be, unless using it as a dedicated sub, xmax is pretty low on the list of things to worry about. Allows some of the more bonkers ideas to be.. a little less bonkers.

    I just plugged the SB racetrack PRs in WinISD. Can get a roughly similar f3 to 2x epique PRs, but needs 15liters to do it.

  • edited August 25

    Yeah but have you ever used "Faital" attraction or "Morel" dilemma while discussing someone's speaker builds?


  • @DrewsBrews said:
    I just plugged the SB racetrack PRs in WinISD. Can get a roughly similar f3 to 2x epique PRs, but needs 15liters to do it.

    How much mass did you add to the PRs? Your measured parameters?

  • edited August 25

    @silverD said:
    How much mass did you add to the PRs? Your measured parameters?

    No added mass. Just dorking around with factory numbers and box volume sofar. Still getting used to how to tune these things.

    Ok, I played around with added mass. Definitely helps on that racetrack PR. That is looking real nice now. When 40g of mass is added in 8liters it is as good or better than 2x epique PRs, though gets up to ~9.5mm xmax on the PR at 50watts. And I don't see a rated xmax on that PR.

  • Can't seem to remember if I went 40 or 60g

  • edited August 25

    Ahh. oops I was just looking at Madisound. I forget to check the manufacturer site too. The SB PR really seems a perfect match.

    "Epique fail" was just a joke about my low skills right now. I came up with a different name. I may have added it to the post between when you read it and posted. There seems to be a few minute lag on posts showing up for me.

  • I joked about Epique Failing in my first post of my build thread too. I'm no expert myself, but the SB PR does model well compared to other PRs. I think I could apply 70W (assuming a subsonic filter is in place) before hitting xmax in driver or PR which is 100dB. Vd of the SB PR is about 1.4x that of the E150HE-44.

Sign In or Register to comment.