[rockadanny]

NewBuyer - Not sure why not, but no missing freqs. except for 55 & 60 Hz, but that is a room suckout for me regardless of filters or not, and regardless of sub settings. I will try adding a second subwoofer at some time in the future to try and resolve this. But back to your concern ...
On paper, perhaps. But that does not take into account my room, which does play an "active" role in the overall effect. Also, my room is far from regular shape and therefore unpredictable. Perhaps it is my room which helps from having the the huge dip?

[Mike Dzurko]

Mike, any thoughts of making more filters for a wider range of choices - both lower and higher in frequency??

Hmm . . . . no, hadn't really given it much thought but it MIGHT be possible to offer a couple more choices. Would help to have some sort of consensus of what the desired frequencies would be. Take a pole perhaps?

[DTB300]

Mike, any thoughts of making more filters for a wider range of choices - both lower and higher in frequency??

Hmm . . . . no, hadn't really given it much thought but it MIGHT be possible to offer a couple more choices. Would help to have some sort of consensus of what the desired frequencies would be. Take a pole perhaps?

I realize there is always a business process of demand for items so they do not sit on the shelves and cost a company money.  Since you already have the 65 and 85, I thought a 45 or 50, 100, and 120 would be good additions.  This would then cover a wide range for many different main speaker abilities.  And it would also give the end user many options to try to find the best way to run their setup.

[NewBuyer]

(Oops  - sorry Mike - I'm deleting this post at Mike's request) 

[DTB300]

You can find some other choices too by Harrison Labsfor instance, for some other frequencies...

From what I read up on them, those are more for the Pro Audio crowd.....but I could be mistaken.  I would love to see Mike put out some others....

[NewBuyer]

...Take a pole perhaps?

P.S. - DTB300, I'm sure Mike didn't mean this as an insult - he probably meant "poll"... 

(just teasin ya Mike )

[Mike Dzurko]

I'm a reguler speling jenios 

[DTB300]

I knew what he meant to say. 

[DSK]

I bought the 65hz and 85hz ACI HPF filters many months ago but only just got around to trying them today.

My main speakers are Selah SSRs (sealed versions) that the manufacturer rates at -3db @ 53hz from memory. Being a sealed box they are subject to 12dB/octave rolloff before adding any HPF's. The sub is a a Rythmik Audio DirectServo (sealed) with 24dB/octave LPF.

The graph below shows the comparison of the mains alone (no HPF), mains + sub (no HPF), mains alone (85hz HPF), mains + sub (85hz HPF). I daresay the slight differences at 125hz or above would disappear if I took multiple readings and averaged them. Measurements were taken at the listening seat (approx 12 feet from speakers) using a tripod mounted RS analog SPL meter (using Rives correction figures).

Just thought the results of adding the ACI 85hz HPF may be of interest to some readers here.



I must say that I was quite surprised at just how much more BIG and DYNAMIC sounding the system is as a result of adding the HPF and increasing the sub's LPF a little to cater for the extra rolloff of the mains. Also, clarity and imaging have increased significantly.

[rajacat]

Thanks for the graph and your conclusions regarding actual sound quality. I think that I'll try out the 85hz HPF.

-Roy

[DSK]

Thanks for the graph and your conclusions regarding actual sound quality. I think that I'll try out the 85hz HPF.

-Roy

No worries Roy. If my sub only had a 12dB/octave LPF I probably would have used the 65hz HPF's to ensure the sub didn't come up high enough to start becoming locatable by ear. Maybe I'll still try the 65's one day but, unless further listening reveals any issues, I don't see the need in my system/room.

[NewBuyer]

Hi DSK,

At what frequency are you dialing the LPF crossover on your sub?

[DSK]

Hi DSK,

At what frequency are you dialing the LPF crossover on your sub?

Here's an updated chart after fine tuning the sub/mains integration further. I'm very pleased with how flat I was able to get the in-room response at the listening position (about 12 feet from mains and subwoofer).



Dynamics, imaging and clarity are remarkable. Tonality is also improved with more personality to each instrument.

[DSK]

Have listened a bit more and found some nice improvements.... more "fatness" and power to low horn notes, more "wail" to electric guitar and higher horn notes, more articulation in the bass (individual notes in drum roll more distinct) and in vocals (warble is more noticeable), transients are quicker and cleaner and leap forward with more vigour, the soundstage is unconstrained, and the "trackability" of panning sounds is remarkable. Also more venue acoustic information and better decay.  Overall a much more exciting and lively presentation with more realistic impact and more realistic sounding vocals and instruments. It actually sounds like a lower noise floor with less between the performers and the listener.   

[jrebman]

Mike,

So what is your "standard" recommendation for Sapphire XLs with a Force XL?  I'm using my RWA Signature 30.2 amp now, and while it certainly has plenty of juice, I'm sure I'll get a lot more mileage out of it with the HP filter.  I have a Dodd battery pre on the way, so setup with the 30.2 will be easy.

-- Jim

[Mike Dzurko]

Hey Jim,

Standard recommendation would be the 85Hz filters. However, as in nearly all things audio, it is often best to try it both ways. I have had a handful of people say they preferred the 65Hz filters with this combo. It is certainly a bit room and setup dependent. You have great ears and really know how to tweak your setup . . .  I'd try them both, starting with the 85s 

[spons]

I received the 65hz filters yesterday and have been experimenting with my Vienna Acoustics Beethoven/Titan XL system since then. Until yesterday I had been using the speaker-level output adapters from my amp into the Titan and using the sub's crossover to fill in under the mains. Intermittantly I have tried stuffing socks in the Beethovens' rear ports to smooth the transition but best results so far have been achieved without them.

To assess the sonic impact of the filters alone I disconnected the sub completely and inserted the filters into my Odyssey Khartago SE and hooked up my Cardas Golden Cross interconnects. A surprising amount of bass and warmth remained, but the addition of the filters flattened the soundstage and reduced treble detail pretty dramatically. I then added a solid Y-adapter to the outputs of my Quad CDP-2 that I use as a preamp and listened again before I hooked up the sub. The result was additional degradation similar to that of the filter alone.

Undeterred, I finally hooked up the Titan and dialed it in using some of my favorite bass-integration music like "Fragile" from Kenny Barron's "The Moment" and "Twilight Song" from his "Night and the City" duet album with Charlie Haden. Wow. Really articulate, deep bass like I have never heard before and no midbass muddiness at all.

My overall conclusion is that I can't accept the degradations that the filter and Y-adapter impose in order to achieve the improvement in the bass and midbass. It is simply a matter of personal priorities as I can understand how another person could feel just the opposite. I returned my system to its original state with the sub running off the amp outputs with no filters or Y-adapter and it sounds pretty darn good. Bass isn't as well integrated but the magical soundstage has returned.

Andy

[DR]

Greetings,

I am one of those customers that prefer the 65Hz crossovers for the Sapphire/Force combination. For my setup, it helps control room events but does not make the force try to resolve men's voice lower registers. Also, the Force is much less localizable ( is that even a word?) 

Switched the 85's and 65's back and forth tonight with Van Morrison's new album and his voice isn't even that low. There was a big difference with just letting the Sapphires handle it from 65. More depth, more color to the voice.

[jrebman]

DR,

That's what I was figuring, so thanks for confirming this.  The lowest notes of the basso profundo can get down to 80 Hz or so even though there is rarely any male vocal content below 100, and 85 just seemed too close especially since I'm trying to avoid the sub localization effect.

I've still got a couple weeks to think about it as my preamp is built.

-- Jim

[DSK]

...To assess the sonic impact of the filters alone I disconnected the sub completely and inserted the filters into my Odyssey Khartago SE and hooked up my Cardas Golden Cross interconnects. A surprising amount of bass and warmth remained, but the addition of the filters flattened the soundstage and reduced treble detail pretty dramatically. I then added a solid Y-adapter to the outputs of my Quad CDP-2 that I use as a preamp and listened again before I hooked up the sub. The result was additional degradation similar to that of the filter alone...

Hi Andy. Much of the soundstage/venue information is in the lower bass. It is not surprising that you heard degredation here with the HPF inserted (and sub disconnected) as much of this information is now gone or at least lower in level due to the increased rolloff of the HPF.

Your observation about the HPF's causing a loss of treble detail is interesting. I have replaced some decent RCA connectors in my system with better ones like the Vampire OFC etc but can't honestly claim to have ever heard improvements by doing this. Also, when you consider the number of RCA connectors in the signal path of most systems, you would expect their cumulative effect to be quite severe and obvious if they do indeed cause treble degredation. IME this hasn't been the case in gear that would be classed entry level high end or better. So, I'm wondering if what you were hearing was an imbalance due to the HPF rolling off more of the bass and the subwoofer not being connected and that this caused a relative increase in treble emphasis that caused your brain to try to address by closing it down a little (ie. de-sensitising a little in this region)? Maybe this would present itself as a loss of treble detail? It's just an "out there" attempt to try to understand why you heard what you heard (I'm no psychoacoustician).    The reason I am puzzled is that I actually heard an improvement in cymbals, brushes, higher freq horn notes, decay and venue information. I can't explain why playing around with bass freqs could improve higher freqs... I can only guess that a full range system is properly balanced to our ears and doesn't skew anything one way or the other. I must say that things sounded pretty good but not great until the subwoofer integration really snapped into place and then it was like flicking a switch. IMHO this is almost impossible to do without properly measuring. It is a painstaking process and takes a LOT of time.

Before you give up on the HPF's, I urge you to get some better Y-adaptors (wire another set of outputs into your pre-amp if possible) and to measure your setup to really dial in the sub with the mains.