Eminence Sigma 18/Yamaha s118

[Phil Starr]

Anyone got any idea why the Yamaha cabs for this speaker are so big? WinIsd comes up with 175l and shows a pretty good response with 100l. My other modeller gives 140-156l for classic alignments.

The Speaker is marked Eminence Sigma and eminence have this data [url="http://eminence.com/proaudio_speaker_detail.asp?web_detail_link=SIGMAPRO18A-2&speaker_size=18&SUB_CAT_ID=1"]http://eminence.com/proaudio_speaker_detai...mp;SUB_CAT_ID=1[/url] . Winisd has slightly different data (Vas slightly smaller).

Are Yamaha trying to squeeze deeper bass out of this with an oversized cab or are they fitting a different version of this speaker? It is a fairly old cab.

If anyone has any information I'd be very grateful

[Bill Fitzmaurice]

Perhaps the cab design pre-dates the woofer, and it was originally loaded with a driver that need a larger box. That, or Yamaha wanted to go lower than what 175L allows. IMO an eighteen loaded cab with a 50Hz f3 makes little sense.

[Phil Starr]

[quote name='Bill Fitzmaurice' post='1059750' date='Dec 15 2010, 05:14 PM']Perhaps the cab design pre-dates the woofer, and it was originally loaded with a driver that need a larger box. That, or Yamaha wanted to go lower than what 175L allows. IMO an eighteen loaded cab with a 50Hz f3 makes little sense.[/quote]
I don't think it's the wrong speaker, though because I bought it second hand, I can't be sure. The original would be Eminence (it say's so on the badge) and they don't advertise a whole lot of 18's.

I agree with you about the speaker making not much sense as a piece of design. It just seems lazy to me, but I might be missing something.With a magnet giving Qts of 0.29 there's leeway for lowering the response or using a longer voice coil as this thing is still excursion limited. Although the set up (s118's with s112V's) sounds pretty good it does seem like someone has said "we'll give them a big speaker in a big box" rather than starting with a design spec.

[Bill Fitzmaurice]

[quote name='Phil Starr' post='1059843' date='Dec 15 2010, 01:35 PM']I agree with you about the speaker making not much sense as a piece of design. It just seems lazy to me, but I might be missing something.With a magnet giving Qts of 0.29 there's leeway for lowering the response or using a longer voice coil as this thing is still excursion limited.[/quote]
It probably boils down to money. You can get a lot more out of an eighteen than the Sigma will give, but the cost would put it beyond the price point that Yamaha can command.