Need design review for planned build - Page 2 - Home Theater Forum and Systems -

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post #11 of 16 Old 10-11-11, 12:34 PM
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Re: Need design review for planned build

I still say port it, I find it hard to recommend this driver as a sealed application. That said, if you must go sealed its not a case of this driver simply wont work, its just not best suited. It will mean a compromise in performance, but if your happy with the end result in a sealed cabinet, then I guess all is well.

The sloping response you see is the raw response of the sub. This is how all subs respond till they are eq'd. If you take the 20hz output as your max spl level, then higher frequencies will be eq'd down to make the end result flatter. You cant boost the low end up, as that is your maximum performance, but the in room response wont look like that. You will need something to do that eq'ing though, so something like Audyssey if you have it, or if not you will need to already have some manual form of eq or buy something to do the job.

Another benefit of the ported system is the low end wont need eq the same, as the port effectively does this by boosting the low end up. So, with the ported, you get more output for free (well you have to compromise with a larger cabinet) and you get some free style effect at the low end as well. I prefer sealed subs no question, I am probably the HTS ambassador for sealed designs, but I still think you should seriously consider porting this to get the most from what you have.
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post #12 of 16 Old 10-11-11, 12:51 PM
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Re: Need design review for planned build

I'm not going to try to change your mind or steer you to something else, especially since you I've already bought stuff. These are nice subs, you could be trying to run much worse combos quite frankly. Add the servo capability and it's really a pretty slick setup.

A bigger box would mean a shallower roll-off and more output in the 10-20Hz range, would also mean a lower total Q meaning better transient response due to less damping on the sub, although also less power handling. A smaller box would handle more power, but the roll-off would be steeper. Going smaller doesn't sound like what you want.

A really good sealed sub might have an f3 in the 30s, or lower, compared to this one at roughly 41Hz. A good shallow roll-off will cooperate with your room gain meaning less extensive EQ needed for flat FR. Does your H600PEQ amp have an auto-EQ function or is it all manual? What is the extent of the servo operation, do you know?
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post #13 of 16 Old 10-12-11, 06:18 AM Thread Starter
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Location: Parrish, FL
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Re: Need design review for planned build

I'm still here.


I hear what you are saying, but I can't go bigger on my enclosures. My setup is in a common living area, not a dedicated HT space, so I have to compromise a bit to keep everyone happy. Your information and opinions are valuable in that at some point in the future my living arrangements may change, allowing a dedicated space, and I can build new cabinets that will better optimize this equipment.

Also, thanks for the brief tutorial on how to EQ the sub for better response. My AVR has Audyssey on board. The amp itself has a single band PEQ as well as an extension filter for additional adjustment.


The amp is all manual. I need to better understand how the servo operates before being able to go into a discussion. My enclosure design has a gross volume of 4.4cf. Bracing is ~.13 cf and the sub/amp take another .4cf, for a net of 3.9cf. That is about as big as I can go. Rythmik recommends 3.5 to 4.0, NOT ACCOUNTING for the sub/amp. They also have told me that going up to 4.4 cf will help the low end performance.

Throughout this discussion I'm getting the understanding that the 600w rms amp is probably overkill for my design and that I won't be able to utilize that much power without risking damage to the driver. Also, that if the internal volume is decreased, I could use more of the amp, but that would not necessarily improve performance of the sub itself. Simplistic I know, but is that right?

Time to leave for work. I'll be back latter.


Last edited by BluesSailor; 10-12-11 at 09:17 AM.
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post #14 of 16 Old 10-13-11, 04:27 PM
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Re: Need design review for planned build

I'd go sealed 4.5cf, 270w per. The 2~3db output diference might not be worth the group delay issues down low if he prioritizes SQ.

with that PEQ set to Fc =80 Q= .7 (Bandwith knob = max) boost =-3, then delay the top end 7ms. it would be nice.

Last edited by revboden; 10-13-11 at 04:41 PM.
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post #15 of 16 Old 10-17-11, 12:14 PM Thread Starter
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Re: Need design review for planned build

Update - I traded a couple of emails with Brian Ding at Rythmik. From those exchanges I learned that the Xmax is 20mm and Xmech is 30mm.

Brian said that this amp/driver pairing in a 4cf +/- enclosure should perform well.

I now have WinISD up and running at home compliments of a PC from my son. I'm still not sure what I'm looking at for excursion other than the comment made by Moonfly concerning the use ofa 300 W amp allows the design to hit Xmax at 20Hz.

Living and Learning.

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post #16 of 16 Old 10-17-11, 12:21 PM
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Re: Need design review for planned build

In WinISD, on the cone excursion chart, you should have a red live at the excursion limit, and ideally you dont want to exceed this.
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