Spawn of Frugel-Horn

[Scottmoose]

Aiko 1st build. I gather from Dave & Chris they need work at present as they aren't performing as we hoped (for which I take full responsibility). The back-chamber seems the most likely culprit at present. But they look great, so we're working on it... watch this space.

[vladimir]

Originally posted by Scottmoose
Aiko 1st build. I gather from Dave & Chris they need work at present as they aren't performing as we hoped (for which I take full responsibility). The back-chamber seems the most likely culprit at present. But they look great, so we're working on it... watch this space.

What's wrong? Nasal coloration? Could you give us more detail? Negative experiences are often more valuable than simple success stories...

[Scottmoose]

Oh, I entirely agree. We tend to learn more from them.

I don't have many details as yet, but there's colouration at ~300Hz which Dave reckons is likely the 1/2 wave vertical resonance mode of the back-chamber. Bass is also a bit weak -as I didn't design extension into these, but went for gain higher up, either the drivers need more hours on them, or the Factory specifications are out. Dave & Chris are putting another hundred hours on the drivers to make sure they're completely broken in before we start making any changes.

[chrisb]

Originally posted by vladimir



What's wrong? Nasal coloration? Could you give us more detail? Negative experiences are often more valuable than simple success stories...

Vlad - that pretty much sums up our first observation- not unlike what we've experienced with the first go-round on the A126, which was easy enough to resolve. Fresh out of the wrapper, these little cuties are definitely doing some very nice mid range things.


Scott - it's too early to conclude the enclosure design is entirely at fault - our expectations could be influenced by the cost of the drivers, and the elapsed time for build completion ( too many projects at once, means that none get finished "on time")
.
This wouldn't be the first time we've experienced this exact type of midrange coloration on a carefully calculated design - the Fostex FE103 BLH for example, as well as the aforementioned original A126

As for LF performance, it could well be that specs and modeling overestimate the driver's final in room performance. The FE108E Sigmas destined for later install should tell us a lot more, but we'll need to wait - I can't see building another pair of these right away.

[Scottmoose]

Thanks Chris -I reckon it'll be fixable. For your and Dave's comments, it sounds like it'salmost certainly the chamber. I wonder if it'd be possible to build out the front, just at the middle, to give an extra, say, 30mm depth to the chamber. That would give a whole lot more volume, and might help. Perhaps it could be integrated with the suprabaffle somehow. Something to think about for future work anyway.

[chrisb]

Originally posted by Scottmoose
Thanks Chris -I reckon it'll be fixable. For your and Dave's comments, it sounds like it'salmost certainly the chamber. I wonder if it'd be possible to build out the front, just at the middle, to give an extra, say, 30mm depth to the chamber. That would give a whole lot more volume, and might help. Perhaps it could be integrated with the suprabaffle somehow. Something to think about for future work anyway.

Yup, that sounds like a plan- we're crossposting on this subject on FRD forum as well.

It would be relatively easy to add depth to the CC by spacers under the suprabaffle - but I wonder about adding some width as well?

[planet10]

Originally posted by vladimir
What's wrong? Nasal coloration? Could you give us more detail?

In this case the colouration wasn't exactly as the FE126 in the early A126 (or the FR125 in the PAWO) which was a too small a CC. The nature seemed more localized. Jeff suggested it seemed to be circa 250 Hz, which a back of the brain calc is about the same as a 1/4 wave resonance of the height of the CC (it does open into the horn, so i figured 1/4 wave was not far-fetched). We'll learn more once we start playing -- we do need to take driver break-in out of the equation, and since the Saturday session (where they had-had 20-30 hrs on them) i've added another 60-70 hrs to them and they are definitely changing... bass is improving, and some of the mid colouration is going away (or i'm just getting used to it). Sometime next WE i'll start compariing them to some references (Fonkens) and we'll see where they have gotten too...

Do have a look here http://fullrangedriver.com/forum/viewtopic.php?id=1581 post 20 for more comments.

dave

[germpod]

Some photos of my finished harveys.

[planet10]

Originally posted by germpod
Some photos of my finished harveys.

Sound?

And can you send me some big images?

dave

[Scottmoose]

Drool. Those look very nice.