[rhino2]

I am modelling two setups..... two LMSR 15's vs two Ultimax 18's in a 500 liter (17.5 cubic feet) box tuned to 15hz. I get a slot port length of 4 by 24 inches wide for 56 inches long. At 1000 watts both of them seem fine for excursion, and port velocity is 17 which seems decent. The 15's graph nearly dead flat from 15hz up through 200hz at about 117db. The 18's taper off quickly in the upper and lower frequency ends but have almost 120db around 40hz.

Am I missing anything obvious?!!?? Just looking for someone to double check my work and make sure I didn't overlook anything.

I am thinking about powering them with an inuke 6000.

The 2 TC sounds 15's will be about $250 more than the 2 Ultimax drivers for similar performance..... If you had to choose which would you get?

 

[chrapladm]

What is the Le for both woofers?

TC has always been known to have very low distortion woofers. But without looking I dont know. Most likely this is the answer though.

 

[rhino2]

TC sounds is 3.15mH and the Ultimax is 2.22mH.

 

[chrapladm]

I was thinking of something different when I read this. What does the Transfer function magnitude tab look like?

I know the UM18 likes a large cabinet so you might need to have a larger cabinet for a smoother response. 17cuft and 15hz sounds sound like a good goal but not all woofers are the same. Some will perform very well and others will need a larger or smaller cabinet to function as well.

 

[rhino2]

 

[chrapladm]

WOW......I will add the UM18 and simulate myself. According to your simulation it looks like the 18 wants about double the size you have there. I didnt think it needed that much but I dont simulate the 18 very often. But I do believe the 15 wants quite a bit of room by itself in a sealed cabinet.

The 18UM wants about 21cuft for a 15hz tune and a F3 of 12.5hz. BUT after simulating 17cuft and 15hz port it looks pretty good with an F3 of about 13hz. So you just have some parameters inputted incorrectly I believe.

 

[rhino2]

That's why I wanted someone to double check. This is with 2 drivers in one enclosure.......

 

[rhino2]

Is that why it looks like it needs to be larger?

 

[rhino2]

I had 2 subs in the enclosure... Were you looking at just one at 17 cubic feet?

 

[rhino2]

 

[rhino2]

Anyone else have any advice for me? Does everything look kosher?

 

[chrapladm]

Not sure why I was never getting updates to this. But I had only one sub in the enclosure. So the dual UM18 in 17cuft is going to have a VERY peaky response because it wants to be in 17cuft per 18 for that tuning. The 15's are better for that enclosure as you can tell by the response shape.

 

[rhino2]

Yeah I was trying to get close to the size needed but I knew I was pushing it. I really wanted to try the Ultimax 18's but may have to go back to a known entity like TC. Or go sealed with the 18's.

 

[Steeve-O]

If you are not set on the brand you could model the SI HT18 I think they will require a smaller enclosure but still not as small as the 15".

 

[rhino2]

True. The SI 18's are a great value too. And perform respectably well according to ricci's testing on data-bass. I just can't get over their looks. They look unappealing to me. I would rather spend twice as much and get the tc sounds drivers. Yeah, weird...I know.

 

[chrapladm]

Does it have to be 15hz tune?

The 18's model well but probably need a higher tune. I tend to look at Transfer function tab more than the simple spl response. I like TC but I am more of a SI fan myself. Also TC is all over the place right now with their products. PE is out of them and I am not sure what is going on with the company.

SI 18's on the other hand are a plenty.

 

[rhino2]

16hz would be fine and maybe 17 would too. Yeah I am wondering if TC is going back to selling drivers direct again.