help needed with WinIsd

[oldies]

hi there
the plan is to use a 15" woofer from ~100hz - 500hz in a closed box
I did some on WinIsd, I just want experts take a look at this graph or WinIsd file I attached to see if 121 liter is OK for the application

thanks

[oldies]

F1

[GM]

There's nothing intrinsically wrong with it, so for a first approximation it is fine for just using it over a narrow BW, but no clue if it best meets the needs of all the performance requirements of the complete speaker design once the XO, off axis response, etc., is factored in.

GM

[tvrgeek]

I strongly suggest not using a 15 inch driver for a mid-woofer. From 100, you would be far better off with an 8 even for PA use, a 4 or 5 in in a home. You will not be happy with the 15's ability to be smooth clear up to 500. Yea, even a high priced JBL. I would only use a 15 BELOW 100 Hz.

Now to your question:
The box you show is tuned for an F3 of 55 Hz. If you intent to cross it over at 100, you can use a much smaller box. May I assume this is some kind of PA system?

[oldies]

Originally Posted by GM

There's nothing intrinsically wrong with it, so for a first approximation it is fine for just using it over a narrow BW, but no clue if it best meets the needs of all the performance requirements of the complete speaker design once the XO, off axis response, etc., is factored in.

GM

thanks buddy

Originally Posted by tvrgeek

I strongly suggest not using a 15 inch driver for a mid-woofer. From 100, you would be far better off with an 8 even for PA use, a 4 or 5 in in a home. You will not be happy with the 15's ability to be smooth clear up to 500. Yea, even a high priced JBL. I would only use a 15 BELOW 100 Hz.

Now to your question:
The box you show is tuned for an F3 of 55 Hz. If you intent to cross it over at 100, you can use a much smaller box. May I assume this is some kind of PA system?

actually it's going to be used in a horn speaker. the 15" will be in used from 100hz - 500hz behind a 100cm horn

[tvrgeek]

I see the attraction for efficiency, but I still caution about the smoothness of a 15 as high as 500. I don't have fond memories of speakers like this. They were common in the '60s. VOT for example. They are still quite common for PA systems where very high SPL is required. To my ears, it is still a poor design choice because the cone just will not behave as well as you would want. For a PA, I would use 4 8's in a line array over one 15 any day. In all fairness I have not had the money to see if drivers like the AE TD15 really can behave the way you are wanting. $300 each is a lot to just see as I have no use for a system like that. Even they don't publish a chart. One thing I do believe, the AE can go down as far as you need it, so if that is you main woofer, you don't need subs. Don't want to sound like an add, as I have no relations with any company, but notice AE does make versions of their 8 and 10 specifically tuned for horn use.

[GM]

Originally Posted by oldies

thanks buddy

actually it's going to be used in a horn speaker. the 15" will be in used from 100hz - 500hz behind a 100cm horn

You're welcome!

Then depending on the horn's design and application, it may not be a good alignment.

GM

[dumptruck]

Originally Posted by tvrgeek

I see the attraction for efficiency, but I still caution about the smoothness of a 15 as high as 500. I don't have fond memories of speakers like this.

Like the JBL Everest, you mean? It's all about the implementation.

[tvrgeek]

Originally Posted by dumptruck

Like the JBL Everest, you mean? It's all about the implementation.

Altec Voice Of The Theater, not to mention things like Hartly, JBL PA's used in houses and others. I just don't like my cones to be flopping in the breeze. It is all about that " perfect piston" mythical goal.

I will grant you some progress has been made in cone shape, small advances in paper, and some advances in doping materials. Small. These are things that were understood in the '50's. Read AES. Unfortunately, we still just can't make them. What we CAN make is far better motors and suspensions that allow greater Xmax while keeping the distortion in check. An 8 may just do a lot better now even though it is moving five times as far.

Another thing we have now is very very good amplifiers. OK, even I have a 8W tube amp, but it sits on my shelf looking cool. I prefer my Parasound 1200's. My smallest amp is a 30W Creek and it is for background music. I remember when 30W was awe inspiring.

For residential use, direct radiators of upper 80's efficiency do very well. PA use is totally different. You need the 90's. I may prefer a line array of 8 8's with a monster amp, but I can see the attraction of a single mid-bass horn that won't dim the lights. What I just don't see is using a 15 in it.

Summarizing, taking all things into consideration, I don't think a 15 is the best for this application. It might have been 40 years ago. There is no one right answer, a few wrong ones (4 inch subs) and about as many in the middle as there are people who ever built a speaker. It takes a lot of thinking about all the tradeoffs working together. I have seen so many speakers built that maximize one parameter, but the end result is terrible. Bose, Klipsh, Walsh, and the list goes on. The reason for horn loading is efficiency. That gives you both lower harmonic distortion and higher SPLs, all things being equal. All things are not equal in the behavior of the cone. Build both and let us know.

[more10]

actually it's going to be used in a horn speaker. the 15" will be in used from 100hz - 500hz behind a 100cm horn

Then you should simulate using Hornresp. Winisd is completely useless in this case.