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Subwoofers and LS3/5As

These two specs are contradictory IMO. Does the AB1 really have a high-pass filter on it at 55Hz to make it a band-pass or is it a typo? If there is no high-pass on the B110 then by definition it's a subwoofer surely, regardless of how low the B110 is able (or unable) to extend?


IIUC it has a passive low pass crossover in the box @ 120Hz.
The acoustic output starts to fall 55Hz. -3dB? -6dB?
I can't see any evidence of any high pass for the main speakers.
 
I would like to hear from some more ab-1 or ab-2 or 'subwoofer' owners who are happy with their set up, and can talk about the options of running these both in series or in parallel with the main boxes.

Having theory conversations doesn't get us very far. foxwelljsly wants to know about using a sub with his ls3/5a. Me too. Buying a small sub is cheaper than buying pair of bass extenders. I'm not convinced that one would have to lay out as much money as for the Kef KC-62.
 
IIUC it has a passive low pass crossover in the box @ 120Hz.
The acoustic output starts to fall 55Hz. -3dB? -6dB?
I can't see any evidence of any high pass for the main speakers.
This is my understanding too, so why do the specs refer to the AB1 as a "bandpass" system? Seems a strange way to describe it if there is no filter to roll-off the subsonic frequencies :confused:.
 
It's just engineering. Ported speakers, with a few exceptions, have a 4th order rolloff which has inherently poor group delay. Some people are sensitve to this, others seemingly not, and some like this effect. ...
As you possibly suggest I think there is a solution to the ported 'speaker transfer function equation that has 3rd order roll-off rather than 4th; and the other thing I suspect is that if you can design the port tuning frequency low enough then the rise in group delay starts to happen when the energy in a lot of natural music is dropping off. The impact will therefore become rather less apparent. Have I got that thought wrong?

If I am right, I suspect the comment I often see that ports are always bad is another generalization where the reality is more like "it depends".

I certainly have heard loudspeakers with small drivers and (I assume) rather high port tuning frequencies that don't sound right in the bass from natural instruments. The bottom end of the piano for example. But I have heard others with larger drivers and low-frequency port tuning where to me the bass from natural instruments sounds fine. It may be different on synthesized lower frequency higher amplitude bass, of course.
 
This is my understanding too, so why do the specs refer to the AB1 as a "bandpass" system? Seems a strange way to describe it if there is no filter to roll-off the subsonic frequencies :confused:.

I suppose "bandpass" applies to everything in the end :confused:
 
As you possibly suggest I think there is a solution to the ported 'speaker transfer function equation that has 3rd order roll-off rather than 4th; and the other thing I suspect is that if you can design the port tuning frequency low enough then the rise in group delay starts to happen when the energy in a lot of natural music is dropping off. The impact will therefore become rather less apparent. Have I got that thought wrong?

If I am right, I suspect the comment I often see that ports are always bad is another generalization where the reality is more like "it depends".

I certainly have heard loudspeakers with small drivers and (I assume) rather high port tuning frequencies that don't sound right in the bass from natural instruments. The bottom end of the piano for example. But I have heard others with larger drivers and low-frequency port tuning where to me the bass from natural instruments sounds fine. It may be different on synthesized lower frequency higher amplitude bass, of course.

I think that's right.

I can only offer opinion based on listening, that I find group delay at very low frequencies more undesireable that at higher frequencies. Maybe this is because the delays (time constants, or whatever you want to call it) are longer? I accept that they are also further from the energy rolloff you mention.
I speculate that this is due to our development as creatues that need(ed) to identify the location of predators and the ear/brain gets more descriminatory at LF.

FWIW I thought the bass produced by Kudos Titans to be excellent. They are ported and isobaric... I have no idea how that translates to group delay, but my ears/brain tell me it works well.
 
Thanks for your reply.

I am running late. Please accept my apology. I'll get back to you tomorrow.

Apologies again for not responding yesterday as I've been extremely busy over last couple of days.

Anyway, if budget permits then JL Audio's E Series and their E-110 subwoofer is also worth a look. The E-110 can slot in between the 34 and QSP. The E-110's on board crossover can deliver high pass filtered outputs (with the LS3/5A's ideally between 90Hz - 120Hz) to the QSP. This creates a true two way 24 dB/octave LinkwitzRiley crossover between the subwoofer and the mains.

Btw, amongst their other qualities JL Audio subwoofers are high speed designs. The best in the business. The Formula 1 of subwoofers. Therefore if they're carefully and correctly aligned, calibrated, dialled then they can make the most profound difference to the overall performance of your system.
 
…and simply your opinion based on your needs. I do not need a subwoofer to suspend disbelief… and for me that is what a HiFi system is about.

I've had similar comments before. Fortunately after experiencing the benefits of correctly aligned, calibrated and dialled in subs an ever increasing number of people are incorporating and supporting their music systems with a subwoofer regardless of the capabilities of their mains. A few more examples -

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100536377_1547969408691442_2077043757689077760_n.jpg


Anyway, I hope that perhaps in time you'll also appreciate the benefits of a sub/sat system and join the club.
 
Been there, done that. I wouldn’t assume that because I prefer to run my setup without subwoofers that I have always felt that way. I’ve owned and run some pretty well respected subwoofers. In the end I prefer to run without them.
 
Been there, done that. I wouldn’t assume that because I prefer to run my setup without subwoofers that I have always felt that way. I’ve owned and run some pretty well respected subwoofers. In the end I prefer to run without them.
Same here. Now I only use a pair of good floor standers with a f3 of 35 Hz and very happy.

 
These two specs are contradictory IMO. Does the AB1 really have a high-pass filter on it at 55Hz to make it a band-pass or is it a typo? If there is no high-pass on the B110 then by definition it's a subwoofer surely, regardless of how low the B110 is able (or unable) to extend?

No typos. I found the specs online and they exactly match those in my manual, but save tedious typing.

You are right in saying that the specs call it a subwoofer. It is however also described as an Auxiliary Bass Unit. (AB1..:)) And yes it does have a high pass filter. However, since the AB1 is effectively just a separate chamber housing a reflex ported driver and a filter.. the whole setup might be better regarded as a floorstanding speaker in which there are two boxes,or chambers, one infinite baffle, and the other ported. In single wired form, the speaker cables enter at the bottom rear of the AB1 and then what is passed by the filter, emerges from the top of the AB1 and connects to the LS3, or Studio 3 in my case,via links. I use further short links to the HF terminals since I decided that Bi wiring is bollox.

Since my AB3s were a bit of a one off, made for me by Andy Whittle, I only have the AB1 manual. There was never an AB3 manual as AB3 never went officially into production. I can't therefore say what the exact characteristics of the filter in my AB3s are... though I was assured it is different, to match the characteristics of the S3 (quoted as 80Hz-21kHz+/-2dB). Impedance of the S3 is nominal 8 Ohms and reputedly stays above 6 Ohms through most of the range, presenting a relatively benign load. Sensitivity is 85dB/2.83v/1metre. All different to LS3/5A

It is pretty obvious that there exists a theoretical possibility of a sonic mismatch between the Rogers' own mid bass driver in the S3, and the B110 in the AB1/3, but I can't say I hear anything. Both are 'plastic'. Polypropylene in the S3 and I think Bextrene in the B110.

Sonically, I just get a bit deeper bass. (And a replacement for poncy speaker stands.) But crucially, I do not lose any of the lightning speed, clarity and tonal accuracy of the S3. My usual test is Ashkenazy playing Mozart piano concerti. The S3s always kept up with him..though to me many otherwise decent seakers don't..and this speed was not diminished and maybe enhanced by the addition of the AB1/3.

My speaker set up has to live in a fairly space constrained environment, but one which is not 'near field'. My normal listening position is almost 5m from the speakers. At present I'm listeninig to Roy Orbison from another room..through an arch..so stereo isn't there but the sound is still very listenable.

Much like myself.. my speakers are refined and not coarse, shouty or bombastic. But also like me.. they can rock when required. :D
 
A year? That deserves a medal.
It’s believable! I use a pair of Quad S1s in my office system - I can’t accommodate anything bigger on my desk. They sound absolutely wonderful, but their bass response is… well they’re tiny and they have 4” woofers, so you can probably guess.

So I bought a BK Gemini and subsequently spent several months tweaking the level, crossover, and position until it sounded right. And now it sounds excellent. The Quads now sound like a pair of big standmounters. Integrating a sub into a 2ch setup for music is not a plug-in-and-forget job, and in a proper listening room I would indeed prefer to choose appropriate speakers in the first place, but it is worth the effort if need be.
 
The result of my research so far is that LS3/5As sound MUCH better with high quality bass extenders.
 
I’ve had a pair of Spendor Classic 4/5 in a 4.5m x 4.5m room, some of which is a window bay and chimney alcoves. Overall they worked really well, and gave surprising presence and bass response (at times), even well out into the room when being listened to, say 50cm from any wall, 2 metres apart, 2 metres from the listening position, angled in. They disappear, image amazingly and were utterly coherent.

Weirdly, in the smaller bedroom next door (4m x 3.3m), they sounded a bit lost and lacked weight! Room acoustics I guess.

In the end, and after lots of agonising over it, I sold them and decided to upgrade to the Spendor Classic 3/1’s (due for delivery mid-March), which are a different beast. Ported and go a fair bit lower in the bass. When I first demoed them, I found them a bit much for the room and found the smaller speakers were a bit more involving in some ways. However, after keeping the 4/5’s for a while longer, I continued to feel dissatisfied with the level of scale and bass on offer (tried a sub, didn’t get on with it). While a sub added bloom, depth, and to a degree, scale (although the latter felt a bit artificial), it was a pain to integrate well, and I felt I was always faffing, depending on the track in question.

Regardless of following all the setup guides (admittedly by ear, without dsp), I was subtly aware of the sub at times. Coupled with the extra cables, clutter etc, I gave up on the idea. Yes, I am sure (a pair) of perfectly integrated subs could give great results. But I had neither the inclination, floor space or patience to go down that route.

So I then re-demoed the 3/1’s and gave them more time, but paid particular attention to playing with positioning, and tried them in other rooms in the house, and ended up preferring them, as an all-rounder, with more convincing scale and depth, better tone and texture of bass compared to the 4/5s with a sub, yet retaining (most) of the smaller speakers' other virtues. I think a lot of the initial feeling of ‘these may be too much for the room’ was as a result of not giving them a fair chance, and therefore not getting acclimatised to them (having been so used to the limited bass response of a ls3/5a type speaker, which was the norm of what my brain was used to).

Of course, ls3/5a types will always win out on imaging, coherence, disappearing, midrange speed, flexibility of positioning, but I also think that slightly bigger speakers of the same ilk (e.g. the 3/1s or the Graham ls6 etc) can get nearly there in those attributes, but have a significant advantage in the area of scale and depth, making them more adept all-rounders.

Bass extenders mentioned in this thread are an interesting one - would love to hear them...but they're certainly pricey, and I suspect I would have been left thinking ''why didn't I just buy bigger speakers?''. However, without hearing them, I am no authority on the subject.
 


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