Subwoofer recommendation for small/medium listening room with JBL 308PMKIIs

[MacClintock]

Hi,

I am setting up my home office room additionally as a listening room. I have already a pair of JBLs 308PMKII and use only streaming with an Airport Express from my iPhone. Now I want to add a pair of subwoofers. Since I am currently living in Brazil, the choices are very limited, as most brands are not even available (so no Rythmik F12) and many are, due to high import taxes, absurdly expensive (like SVS). But luckily there remain some options.

My room has about 4.5 m x 4 m and is 2.5m high (with a wood panel ceiling).
I suppose that due to the room size anything above woofer size 10'' would be overkill (is that true?).

According to the specs of the JBL 308PMKII, they already go down to 37dB, so my understanding is that it is worth investing in a subwoofer which really goes low, otherwise there would not much benefit in adding it.

I made a pre-selection where I exclude most of the offered models, as they become through the import taxes very expensive. For example, the current rate BRL(R$)-USD is about 5, but many models which cost, say, $500 in the US would cost R$ 4500 (and not R$2500).

1. SpeakerCraft (previous Sunfire) SDSi 10 R$ 3200
2. SpeakerCraft HRSi 10 R$ 6300
3. OSD Trevoce 10 EQ DSP R$ 3800
4. KEF Kube 10b R$ 4000

That would be the principal shortlist. There is, of course, the JBL LSR310S, but it costs already R$4300, compared to the offer of USD$ 330 in the US, so I would not be willing to pay this surcharge.

General other criteria are, low frequency (at least 25dB +/-3dB), bivolt, not too large and visually pleasing. It would be nice to have EQ/DSP built in and wireless transmission. All listed ones fulfill all these.

From the SpeakerCraft HRSi, which is by far the most expensive of the list, I haven't seen any CTA/CEA-2010 measuements, but I like very much the piano gloss finish, the brutal beauty of the fibre glass woofer (even my wife prefers the exposed woofer look to the grill of the KEF, which unfortunately cannot be taking of, so much for WAF), and the compact size. But is worth the extra money?

What the CTA/CEA-2010 measurements are concerned, I have found a discrepancy for the KEF Kube 10b in the list of member @sweetchaos (https://docs.google.com/spreadsheet...fyBjaxK69dkXte6ZL6anVTW2_M/edit#gid=834598950) and from Brent Butterworth (https://docs.google.com/spreadsheets/d/1KjlXBWMPAHgU_V9DAHSdIZ_ke0MxwH6ekt3vTIlYOJU/edit#gid=0). So I am not sure what is true here (or which standard was used in each case).

There are even two Brazilian brands (AAT and Frahm), but I am not very convinced.

I would be very grateful for any tips, hints, comments, recommendations, even pointing out of my misunderstandings, as I have no previous experience with subwoofers.

 

[sweetchaos]

What the CTA/CEA-2010 measurements are concerned, I have found a discrepancy for the KEF Kube 10b in the list of member @sweetchaos (https://docs.google.com/spreadsheet...fyBjaxK69dkXte6ZL6anVTW2_M/edit#gid=834598950) and from Brent Butterworth (https://docs.google.com/spreadsheets/d/1KjlXBWMPAHgU_V9DAHSdIZ_ke0MxwH6ekt3vTIlYOJU/edit#gid=0). So I am not sure what is true here (or which standard was used in each case).

I entered his data into my spreadsheet.
His data is presented as 1m Peak SPL.
I have to subtract 6dB from "Brent's data" in order for it to be equal to what i'm showing (which is 2m Peak SPL).
Nothing wrong here.

 

[Chrispy]

Do the subs have similar high pass for speakers as the JBL 310S? Or just the typical low pass for the sub itself?

 

[MacClintock]

Do the subs have similar high pass for speakers as the JBL 310S? Or just the typical low pass for the sub itself?

Not sure, could you please explain the relevance of this?

 

[MacClintock]

I entered his data into my spreadsheet.
His data is presented as 1m Peak SPL.
I have to subtract 6dB from "Brent's data" in order for it to be equal to what i'm showing (which is 2m Peak SPL).
Nothing wrong here.

Ok got it, thanks. Do you have, by any change, data for this new SpeakerCraft series, and the OSD Trevoce 10 EQ DSP, I couldn't find any in the internet.

 

[sweetchaos]

Whatever data you see in my spreadsheet, is what I have.

 

[Chrispy]

Not sure, could you please explain the relevance of this?

I prefer an actual crossover, i.e. a high pass for the speakers and a low pass for the subs for better integration of speaker/sub. I'd rather have something more sophisticated than the simple one in the JBL but it is meant to be used particularly with your JBL speakers (and the others in the LSR series) on the other hand. Most subs these days just provide a low pass filter (often called incorrectly a crossover, tho). The sub will generally perform better at that frequency range than the speakers and frees up some of the amp in the speakers, too.

I took a look at the more expensive of the Speakercraft subs due your comment about Sunfire (which wouldn't be a sub I'd particularly consider), but no indication of such a feature; didn't know Speakercraft did anything but in-wall/in-ceiling sort of stuff and haven't been on my radar much in any case.

The Kef 10b I just looked at, it also just has a low pass filter and suggests using external bass management.

 

[MacClintock]

I prefer an actual crossover, i.e. a high pass for the speakers and a low pass for the subs for better integration of speaker/sub. I'd rather have something more sophisticated than the simple one in the JBL but it is meant to be used particularly with your JBL speakers (and the others in the LSR series) on the other hand. Most subs these days just provide a low pass filter (often called incorrectly a crossover, tho). The sub will generally perform better at that frequency range than the speakers and frees up some of the amp in the speakers, too.

I took a look at the more expensive of the Speakercraft subs due your comment about Sunfire (which wouldn't be a sub I'd particularly consider), but no indication of such a feature; didn't know Speakercraft did anything but in-wall/in-ceiling sort of stuff and haven't been on my radar much in any case.

The Kef 10b I just looked at, it also just has a low pass filter and suggests using external bass management.

As far as I understand it, all the models I listed have active DSP with a dedicated app. But in any case, I am also planning in setting up generally a miniDSP and doing room measurement, I just also have to get into that topic as well.

 

[Chrispy]

The active dsp is for some eq independently of other gear I assume? Do you see yourself fiddling with the app/remote all the time? A minidsp is one of the types of superior external ways to go about bass management for gear that doesn't have it. Do you use volume control from your streamer or on the speakers themselves?

 

[MacClintock]

The active dsp is for some eq independently of other gear I assume?

That would be for both, subwoofers and speakers.

Do you see yourself fiddling with the app/remote all the time?

No, I think you go through all the process with measuring and fiddling once, until everthing is correctly set up and leave it like this, at least that would be the plan.

A minidsp is one of the types of superior external ways to go about bass management for gear that doesn't have it. Do you use volume control from your streamer or on the speakers themselves?

Before I had a streamer that only puts out 0.9 Vrms, that did leave the speakers not loud enough for me, now I bought an Airput Express with 2Vrms output, which has sufficient power, I tested it with my Topping Dx3Pro+, which also has 2 Vrms. The volume control is then from my phone, leaving the JBLs at maximum level.

 

[Anthony LoFi]

Integrating a sub is really difficult if you are wishing to take advantage of really good stereo speakers and a "normal" room with no problematic boundaries.
Finding the correct cross-over frequency, gain structure and phase relationship for both speaker systems.
I think the terminology used currently where we say we want a "sub" is not to add home thearter effects but to expand our stereo system to extend below our standard 40Hz - 20 K Hz range.
What we are wanting is a full range speaker system from 20 Hz to 20k Hz.
A number of high quality manufacturers do this already. I believe manufacturers will be looking to designing such system in the future as amplification is now economical and small/low temp (Class D).

I think before a sub is selected we should be looking at how our signal chain is going to supply the L/R Mains and the sub.
Finding the cross-over point and then phase aligning both signals will need some for of DSP.
This will depend on way your are looking to provide signal processing and separate amplification.
You may have limited signal preamp/power amp abilities so need to look at purchasing the sub that can be future proofed to when able, used with a room eq system in the future.

May I suggest the Neumann KH 750 DSP. In Australia they are priced around $2K which I believe is very reasonable for what you have in an active sub.
Its twice the price of the Kef Cube but really think looking at a quality product second hand may be a considered option?

 

[Chrispy]

That would be for both, subwoofers and speakers.

No, I think you go through all the process with measuring and fiddling once, until everthing is correctly set up and leave it like this, at least that would be the plan.


Before I had a streamer that only puts out 0.9 Vrms, that did leave the speakers not loud enough for me, now I bought an Airput Express with 2Vrms output, which has sufficient power, I tested it with my Topping Dx3Pro+, which also has 2 Vrms. The volume control is then from my phone, leaving the JBLs at maximum level.

DSP for speakers built into the subs? Have an example? Didn't notice anything like that kind of capability in my brief look at the manuals.

Yes, having sufficient output voltage is a good thing. At the -10dB input sensitivity setting for my 305s with my pre-amp I've had no issues, but I've used it only with old school 2ch analog pre-amps and pretty sure they're outputting at least 2V. Don't No particular issues with hiss leaving the jbls set at full gain?

 

[MacClintock]

Integrating a sub is really difficult if you are wishing to take advantage of really good stereo speakers and a "normal" room with no problematic boundaries.
Finding the correct cross-over frequency, gain structure and phase relationship for both speaker systems.
I think the terminology used currently where we say we want a "sub" is not to add home thearter effects but to expand our stereo system to extend below our standard 40Hz - 20 K Hz range.
What we are wanting is a full range speaker system from 20 Hz to 20k Hz.
A number of high quality manufacturers do this already. I believe manufacturers will be looking to designing such system in the future as amplification is now economical and small/low temp (Class D).

I think before a sub is selected we should be looking at how our signal chain is going to supply the L/R Mains and the sub.
Finding the cross-over point and then phase aligning both signals will need some for of DSP.
This will depend on way your are looking to provide signal processing and separate amplification.
You may have limited signal preamp/power amp abilities so need to look at purchasing the sub that can be future proofed to when able, used with a room eq system in the future.

May I suggest the Neumann KH 750 DSP. In Australia they are priced around $2K which I believe is very reasonable for what you have in an active sub.
Its twice the price of the Kef Cube but really think looking at a quality product second hand may be a considered option?

Well the Neumann's are neither available nor nor in the price range I aim at, especially as I want 2. As I mentioned, all the 4 subs from the list have built in DSP/EQ with a dedicated app, and if this will not generate satisfactory results I will go for the miniDSP.

 

[MacClintock]

DSP for speakers built into the subs? Have an example? Didn't notice anything like that kind of capability in my brief look at the manuals.

See for example here: https://www.intoavdistribution.com/product/speakercraft-sdsi-10-subwoofer/
"The HRSi Series comes in a luxury piano black finish made from 1″ MDF. Each subwoofer has a 1000 watt amplifier. Uses high back EMF Fiberglass drivers. This also has integrated wireless audio capability and is app based DSP with Auto room correction."
Or here: https://uk.kef.com/products/kube10b-subwoofer
"Kube subwoofers offer unmatched set up flexibility. A range of LFE, line and speaker-level inputs, phase selection and DSP controlled EQ settings help you get the best from a Kube."
Or here: https://www.osdaudio.com/trevoce10-...pp-controlled-dsp-native-eq-faux-leather.html
"*NEW EQ DSP, The new native EQ added to the Trevoce line has allowed us to extract the maximum bass extension possible from our design, reaching 25Hz. This allows the full range of musical instruments and special effects to be reproduced."

Yes, having sufficient output voltage is a good thing. At the -10dB input sensitivity setting for my 305s with my pre-amp I've had no issues, but I've used it only with old school 2ch analog pre-amps and pretty sure they're outputting at least 2V. Don't No particular issues with hiss leaving the jbls set at full gain?

Even when I am working on my desk and pretty close, I don't recognise the hiss, I was more worried before I aquired the speakers reading about it. The fan fro my laptop is much louder. Adn when on my sofa listening to music I am too much away anyways.

 

[Chrispy]

For the Speakercraft that's just for the sub, and is a nice feature (if it works well), but it has no way to affect the speakers particularly.

The Kef's LFE/line and speaker level inputs are unremarkable as they're fairly typical (altho speaker level inputs are starting to disappear on some subs). Phase (polarity) is typical. DSP controlled eq just means it's not analog eq, and it has three pre-set positions (in room, corner, wall/cabinet) to account somewhat for boundary gain or not. Nothing you can adjust otherwise for dsp. I didn't look at the OSD. Look at manuals and controls, not just the marketing blurbs.

 

[fishergod]

The Polk HTS-10 is surprisingly good in my experience even in a bigger room. Thumbs up on that one for sure.

 

[MacClintock]

The Polk HTS-10 is surprisingly good in my experience even in a bigger room. Thumbs up on that one for sure.

It sounds like a relatively cheap, good option and is even available here, but unfortunatley I don't like the design.

 

[fishergod]

It sounds like a relatively cheap, good option and is even available here, but unfortunatley I don't like the design.

Oh that feeling about the design is mutual.