Axiom Home Page Forums General Discussion Stereo Researching Sub Purchase - Connections

While my AX2s & Velodyne F1000 sub (in the Wall O'Fame) are still performing as new in my audio only system, I expect that my F1000 is in its twilight years & will need to be replaced in the next while when it finally dies. According to Velodyne, replacement is the Optimum 10 that looks like a good, accurate sub for a music only system.

I drive the 3 speakers with a new, basic Sony Stereo Receiver that has no LFE nor PreAmp Outs (Tape Mon Out only). Therefore, I use the Speaker Level Output to the sub with a long speaker wires underneath the baseboards (hardwood floors). The F1000 has Speaker Outs that filter out the low freqs before sending to the AX2s. This is what I prefer as the mains do not have to try to reproduce the bass spectrum for cleaner sound.

Fewer subs are being produced with this capability as most receivers now have LFE Out. The Optimum 10 & the Axiom subs (350, 400 or 500) that I'm also considering do not have the filtered Speaker Out capability. In my HT system, my twin Velos DLS-3750s have the Speaker In & filtered Out connections (although I don't use them here) as do Velo's new EQ-Max series.

Options would be to buy a new receiver with LFE/Sub Out but I really don't want to move furniture & rip up & replace 30' of baseboard if I don't have to. Besides, my Sony is still new & sounds good to me.

Is having the low bass being filtered from the mains (AX2s or perhaps M22s) as important as I think that it is or am I misguided?

Thoughts??

Thanks

Tom
Comox, BC

Tom, i'm not sure why you don't use the receiver crossover (or the sub crossover) to find the appropriate blend of the sub and mains. Does your receiver not have a crossover setting?
If not, the subwoofers all do in the form of a knob on the back.

I have my M60s set to large in my receiver so they play full range, and i've crossed over my subwoofer with its x-over knob to about the 50-55Hz level which is where i find it blends best with the M60s for my bass preference.
As the M60s roll off naturally, the sub picks up around this frequency. If it sounds too full, bloated or muddy, i can turn down the sub x-over or its gain/volume until i find a good mix.

Tom, Paradigm DSP series of subs are nice and I believe have speaker level inputs. Also I know Polk used to recommend this type of set up and therefore my Polk sub has these inputs too.

Actually when I was even more of an HT noob than I am now, that caused me great confusion when my receiver manual said to use the LFE out but my Polk sub manual said to use the speaker level inputs! Glad I'm a little bit more knowledgeable today (I think).

To add to Dan's post....Paradigm recently discontinued/replaced the DSP line of subs, so if you find one it's likely this last year's model or older. The DSP's are nice subs, I own one...their replacements are of the sealed variety with greater driver excursion I believe.

Thanks for the replies.

My new Sony Receiver is just basic stereo, 2.0 only with no fancy LFE nor PreAmp outs. I wanted just a simple 2 X 100W per CH receiver for stereo only. It replaced my 20 year old Sony STR-D2020 from 20 years ago that I used for my audio only system in the connection mode in my first post. The speaker wiring is already in under the baseboards & I want to use it that way, ie Receiver Speaker to 'Sub Speaker Level' In & 'Sub Speaker Level Out' to the mains.

It's not the Speaker Level Inputs that are missing on most subs today - they are normally always installed; however, it is the Speaker Level Outputs that provide filtered signal to the mains that are becoming scarce. Axiom subs do not have Speaker Level Out connections either.

If Speaker Level Out connections are not installed, then the full spectrum of the receiver's Speaker Level Signal is fed to the mains. I would prefer to have the mains not have to deal with the low freqs. This was always touted as the best way to go when sub development was in its infancy, before HT, LFE, etc.

So the question remains - when using Speaker Level connections, is it still preferable to feed small mains a sub-filtered signal vice a full spectrum signal? Based on what I've read over the years I think that it is preferable; however, I'm not an expert.

Comments?

Tom
Comox, BC

Tom, sure it's preferable to limit the bass frequencies that the mains have to handle when a good sub is in use. Forcing the mains to still play full-range in that situation isn't disastrous, but the sub should play those frequencies both more strongly and more cleanly and allow the mains to play more cleanly in the frequencies they handle well.

In your setup you can get a reasonably good blend using the 85Hz high-pass filter on the F1000's speaker level outputs and applying a setting around 80Hz(assuming that the setting is reasonably accurate)on the low-pass filter(not a crossover, although that term is frequently used on the sub frequency control)knob. The blend obtained with the crossover setting in modern HT receivers is more precise, but if you don't want to get into that(which is fine even in 2.1 setups)and wiring the speakers directly from the receiver, you'll continue to rely on the sub's high-pass filter.

Also note that although many current subs do have speaker level outputs, very few have a separate high-pass filter on them, and simply feed the full-range straight through to mains if they're connected.

Tom, i currently have a stereo setup, M60's with a pair of 8" JL subs. My M60's receive the full signal, and i am using the lowpass filter on the sub amps.

In the end i will wind up with a pair of EP600's that will replace the JL subwoofers (need one more 600).


Having talked with John, and Ian. I am going to continue to provide the M60's the full signal, and when i get the 600's i will use their lowpass filter. One thing that may change (which will be determined at a later date) with my specific setup would be a digital crossover to control the signal received by the different speakers i am using outboard amps.

JohnK:

I am using my present F1000 exactly the way that you describe by limiting the lows to my AX2s (crossed at 80Hz) because it has filtered Speaker Level Outs. The AX2s are getting everything above 80 Hz & the F1000 is doing all the work below that - very effectively I might add. That is the only way that it can be done with my present receiver without going to add-on hardware.

For an audio only system, I prefer smaller mains (paired with a quality sub or two) such as the M22. The question is - what is an M22 doing with the lowest bass freqs that it can't possibly reproduce if it is being fed a full spectrum signal? I would think that if it was receiving only 80Hz & above (like my AX2s are) the M22 would be much happier. I surmise that it would not be as susceptable to compression at high SPLs giving cleaner sound & be less stressful on the speaker components.

This is what I'm trying to achieve so my sub choices are definitely limited. I recognize that the vast majority of HT components now do the LFE onboard & can see why manufacturers are not providing filtered Speaker Level Outs as they once did. It now is really an uncoomon, legacy connection system - but that's what I need.

dakken:

Thanks for your input. I'm sure that your M60s would be quite happy with a full spectrum signal whereas smaller mains probably would not be.

Tom
Comox, BC

Tom, the M22's will play down to 30hz at 70db according to the frequency response curve for those speakers. The M22's should be just fine with a full signal, as long as the volume was not too high. Brent or JC would probably be able to answer this specific question about the M22's and having them play "full frequency". The speakers i have in my bedroom are similar to the M3's, and they are also provided with a full signal. For that room (10'X10') they are just fine.

I though the AX2's were towers, hence my M60 story.

The AX2s are actually considered to be bookshelves, although they are really too big for that in most cases. They are also too small to be floorstanding towers & require stands; however, given their 250 Watt power handling capability & 8" woofer, electrically they are probably in the tower class.

Since the AX2s roll off at 40Hz, the F1000 Servo (FR 20-85 Hz+/- 3dB; less than 1% Distortion 25Hz @ 104dB) nicely fills in the lower end for a very pleasing, accurate sound. Of the towers that I've auditioned locally (nothing really exotic) under less than ideal store conditions have not impressed me as much as my vintage setup does. They just don't have quite the bottom end that a good sub can provide.

Perhaps the F1000 will go for another 10 years & I won't have to worry about it, ha!!

Tom
Comox, BC

Tom, I guess wasn't too clear. I believe those Paradigm DSP's and Polk's do have speaker level in and filtered speaker out on the sub.

Adrian - did not know they were dc'd as they are still on the Paradigm site. My local dealer still has a few in stock as I just checked a couple of weeks ago for a stereo setup for my in-laws.

Cheers,

I don't think that any of those have filtered speaker level outputs.

I just checked a random manual from Polk (model PSW111) and they show both the speaker level input with filtered outputs as a setup option. It is also shown in the Paradigm manuals for their subs. That's why I believe they have them included on their subs even though i don't have one to physically confirm.

Obviously there are probably many subs that have them, but those 2 brands came to mind from memory when I was 1st researching & building my HT systems.

Whilst browsing the hot 'Multiple Subs' thread in the HT Section, I read with interest the many reviews of Axiom subs.

This one: http://www.enjoythemusic.com/magazine/equipment/0306/axiom_ep500.htm explains the connection method that the reviewer was trying to accomplish with his unorthodox speaker system, ie wanting to use the sub as a crossover. Essentially I want to do the same thing by using a sub as a crossover to my satellites using Speaker Level Ins & Outs.

This article correctly names this as Speaker Level High Pass Out rather than the Filtered Out term that I've been using.

Tom
Comox, BC

That is a 2006 article and the EP500 amp has been changed a few times since then, you might want to ask Axiom.

I included that article because the reviewer articulated the whole subject of filtering the lows from the satellites better than I did.

I just checked the specs on the entire Axiom sub line & none of them list a 'High Level Out' capability. This is common elsewhere as well. Obviously it is a design philosophy where Axiom does not believe that filtering out the lows to satellites is desireable nor necessary. With all of the blind testing that they do, they probably discovered this a long time ago.

Perhaps we have been fed a line over the past 20 years as to the high desireabilty of this method of connection. I don't know; however, I wish that someone with the technical expertise in this field would provide me/us some definitive information.

Tom
Comox, BC

No, Dan; the PSW111 doesn't have a high-pass filter on the speaker level outputs. If you're referring to what they term connection "Option #2", this is simply the usual full-range pass through to main speakers when they're connected in that fashion. This is often misunderstood to mean that subs with speaker-level outputs have an internal crossover which is adjusted by using the frequency dial on the back of the sub(which often is labeled "crossover"). That control is only for a low-pass filter on the sub itself and has no effect on the main speakers, even when they're connected through the sub; there is no "crossover". In the past some of the Polk subs did have a separate fixed-frequency high-pass filter on the speaker level outputs, but this had nothing to do with the frequency control on the sub.

Tom, sure that's what Axiom and most other sub manufacturers do. It isn't that they don't believe in filtering out the lows to satellites, but the precise way to do this is with variable crossovers present in modern multi-channel receivers. The relatively crude fixed frequency high- pass filter that was present on a fair amount of subs in the past and a very few currently, is certainly better than forcing full-range signals into the mains, but should never be used when a receiver with proper bass management is available.

OK, thanks JohnK, I did misinterpret the setup option believing they were filtered speaker outs from the sub and not a straight pass through - I am now slightly wiser.

I dug out my subs' manuals to refresh my memeory in what I have now.

Audio System - vintage Velo Servo F1000 (connected using Speaker Level Ins & Outs: High Pass Fixed - 85Hz 6dB slope. I have the Low Pass set at 80Hz to blend with the AX2s;

HT System - new twin Velo DLS-3750Rs (connected from Denon 2X Sub Outs to sub LFEs In): High Pass Selectable - 80Hz or 100 Hz 6 dB slope; and

New Velo EQ-Max line - High Pass Fixed 80 Hz.

These features do not appear in all of their other product lines however.

So with my legacy type system, the EQ-Max may be a good option, although no decisions have been made yet....

Tom
Comox, BC

Tom, would any of these work?

http://velodyne.com/shop/subwoofers.html

The instruction manual for the High pass crossover switch

"This switch selects the frequency for the high pass crossover. This crossover is functional on both line and speaker-level outputs. Smaller
speakers with limited low frequency output may perform better using the higher 100 Hz setting that will reduce the low frequencies sent
to them. Larger speakers with greater low frequency output may be able to handle the 80 Hz setting without strain."

Yup, the new EQ-Max series fills the bill perfectly connections-wise with its 80 Hz Speaker Level High Pass Out. Presently I'm not quite sure performance-wise that an EQ-Max is what I want for audio only; however, they will probably be a great HT sub for the money once they go on sale.

I see that Future Shop in Canada has finally received them. Online the 8 incher is $700 CAN. I saw the 12 incher in the local FS Store for $900 CAN; however, a conversatiomn with the floor manager quickly had it down considerably. As I'm awaiting some reviews, I didn't bite.

Tom
Comox, BC