Half chang or Dallas II?

[cwujek]

Opinions? I'm building a set of fullrangers with good bass in mind (I can always add a T90 later if I want a bit better high end). That being said, I'm looking at both the Dallas II and the half chang. I am capable of building either, and was very impressed with my Austion 166s designed by ron. The Half-Changs seem to be a different design concept, but from what I have heard, they sound great. Anyone care to comment? I doubt anyone has built both...

[Scottmoose]

They're completely different, so comparisons are difficult. DallasII requires the 206, HC will be happier with the driver I designed it for (the 207, although you can add a wad of series resistance to the 206 to get its response into line in this box should you wish). They're both tuned to a similar frequency; HC will be an easier build, & probably a touch less delay. DallasII will go louder & will offer more cabinet gain over a broader BW.

[cwujek]

Originally posted by Scottmoose
They're completely different, so comparisons are difficult. DallasII requires the 206, HC will be happier with the driver I designed it for (the 207, although you can add a wad of series resistance to the 206 to get its response into line in this box should you wish). They're both tuned to a similar frequency; HC will be an easier build, & probably a touch less delay. DallasII will go louder & will offer more cabinet gain over a broader BW.

Well, I'll buy the driver to match the cabinet I build. I don't mind the added complexity of the Dallas II, I'm really just after the build that will have the best sound quality. Is cabinet gain referring to the low frequency boost that is created by the longer horn? I would imagine that more cabinet gain over an increased bandwidth would be a desirable characteristic, please correct me if I'm wrong. Delay has never been an issue with the Austin 166's, can you really detect such a small delay when listening? Thanks for your comments Scott, I'm sure I'll build both cabinets at some point, I just need to decide which to do first.

[Scottmoose]

Unfortunately 'best' depends on systems, rooms, material & what people happen to like / want.

Cabinet gain refers to the amount of gain produced by the cabinet. Making a very simplistic generalisation, a small-chamber, long horn works over a broad passband (generally 2 - 4 octaves)because the driver rolls off at a comparatively high frequency. Conversely, a large chamber, short horn, works over a narrower passband because the driver will roll off at a lower frequency, and therefore doesn't need gain from the cabinet over such a wide bandwidth. Both approaches have their positive and negative aspects.

Yes, delay is certainly audible. The longer the horn, the more audible it will become: the lower frequencies have to travel x number of feet further than the HF due to them passing through the horn. Whether it bothers a person or not is a different matter though. Some are, some aren't -you're obviously in the latter category as you already enjoy your Austins.

FWIW, in your position, I'd probably build the DallasII, even though it pre-dates the slightly more advanced Austins. You clearly like the kind of sound Ron's designs will produce, so it would make sense to stick with it.

[hartgas]

Making a very simplistic generalisation, a small-chamber, long horn works over a broad passband (generally 2 - 4 octaves)because the driver rolls off at a comparatively high frequency. Conversely, a large chamber, short horn, works over a narrower passband because the driver will roll off at a lower frequency, and therefore doesn't need gain from the cabinet over such a wide bandwidth

hi scott, could you explain me what the audible differences will be between the both types.
are there also big differences in soundstage between the two types and does the longer horn mean that it supplies more bass? thanks in advance

[Scottmoose]

I'd done that in the words you quoted (albeit you have to read some things into it)

Both should have roughly the same LF extension. I would expect the soundstage to be similar. No, the longer horn does not supply more bass. It would if the driver-chamber was the same size for both designs, but it's not. There are going to be many detail differences between the them; DallasII should go louder without distorting is probably the major one, so would likely be a better bet for a big room if you like to crank things up loud.