2 small sub-bass modules driven by 1 plate amplifier for home office?

Hi

After recently converting to 2 smaller (BK) subs for my main 2 channel system, I am wondering about building a powered bass system for my home office.

The components I am considering are:
2 x Dayton Audio DCS165-4.
Dayton Audio - DCS165-4 6-1/2" Classic Subwoofer 4 Ohm

1 x BSB200
BSB200

The amp is rated at 200w RMS into 8ohms/275 into 4 and AFAIK is what they use in their XLS200 subwoofer. The drivers are 100w/4ohm items.

My plan is to build all three into separate cabinets for flexibility - the sub cabs (small and sealed - not ported/PR etc.) will be stackable if that works best or could be positioned separately for optimum smoothing. The amp will have a separate accessible position. I plan to wire the subs in series (100w each).

The space under my desk is limited, hence small cabinets - I have had a BK Gemini II there before but it was impractical. I’m not trying to produce really low end, rather to support/smooth the area from mid 30hz up to the 65-ish area. The benefits in terms of soundstaging etc. of dual subs in my main system have been considerable and I would like to reproduce this effect if possible in the office system. The main speakers (on the desk) are Mission 731i and amplification is either an AVA Meastro 50 or an Arcam A18.

My main question is whether driving both drivers off a single plate amp will be an effective solution? Also, has anyone else done a similar build - effectively 2 compact passive bass modules driven by a single amplifier?

Regards

Alex
 
Technically it is no different to my AV system where two 3 ohm subs are connected in series to the sub amp.

In practical terms at normal listening levels two small subs in series offer very little enhancement over one. Remove one sub and the resistance is halved so the amp throws twice as much power into the remaining speaker.

Personally, I think 200w may be a bit overkill as a desktop system behave very differently to a more standard placement (especially if your desk faces a wall). You are invariably within 1 metre of an output source. Lower frequency response is almost possible to calculate due to the unusual location. (The underside of the desk acts as the ceiling).
 
6.5s in parallel

Alex,
I'm running two of the 8 Ohm versions in parallel with a 70W plate amp in my office. Fills in the bottom end and blends well with the small, single drivers on the desktop.
Karl
 

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Technically it is no different to my AV system where two 3 ohm subs are connected in series to the sub amp.

In practical terms at normal listening levels two small subs in series offer very little enhancement over one. Remove one sub and the resistance is halved so the amp throws twice as much power into the remaining speaker.

Personally, I think 200w may be a bit overkill as a desktop system behave very differently to a more standard placement (especially if your desk faces a wall). You are invariably within 1 metre of an output source. Lower frequency response is almost possible to calculate due to the unusual location. (The underside of the desk acts as the ceiling).

Thanks for the reply. Sorry I should have said that I listen to music after I have finished working - I’m rubbish at concentrating when music is on...
I’m a teacher so I am work in the office during the evening. I listen to music in the office afterwards as it’s not underneath the rest of the house so I don’t disturb anyone - everyone else is long since asleep!

This is relevant because I move my chair back so I’m about 5ft from the speakers.

I thought of two smaller subs as they could be positioned away from each other to help with evening out low-end response. This worked with my main system so I thought I would try it in the office.

Ref power, the BK seems to be one of the cheapest good quality plate amps available in the UK - I have BK amps in my OE subs and they seem good to me. The lower powered Dayton models don’t seem to be in offered in Europe - presumably because they aren’t produced in 230v versions?

Ref the effect of the desk, I found that when I had a BK Gemini II (too large a cube - got in the way of my chair) the bass response improved when I was sat further away from the desk so what you have said rings true - I just assumed it was due to frequency wavelengths but it seems plausible that the desk prevents output from under desk subs reaching the ears of a listener when sat at the desk.
 
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Alex,
I'm running two of the 8 Ohm versions in parallel with a 70W plate amp in my office. Fills in the bottom end and blends well with the small, single drivers on the desktop.
Karl

Hi Karl

Are these 8ohm versions of the 6.5 inch classic sub? They would be perfect. I can’t seem to find any info on these anywhere. Have they stopped making them?

If you don’t mind me asking, are these in sealed enclosures or ported? What sort of enclosure volume are you using?
This is just the sort of set-up I had in mind!

Alex.
 
Thanks again.
I have found them - they are about £28 each in the UK which seems very reasonable - this has the basis of a fun, effective project. However, it might have to wait a little bit though as the original (factory upgrade) RH front (driver’s side in UK) mid/bass woofer in my Focus ST has just given up - just in time for pulling it out of winter storage and what passes for summer in the UK!

I fitted JL Audio TR 6.5 components in my daily driver Mazda 6 a few years ago and these are great. Getting a pair of the newer C1 650 components would seem to be the most sensible option. Trouble is I have a Genesis Four Channel amplifier and JL 6.5 inch Micro-sub currently sat being very under-utilised in my MGB - just wondering about buying an Audio Control LC2i to go from the factory head unit and swapping the amp and sub from the MGB and doing it all properly.
 
An update - I finally got round to building 2 enclosures for 2 x Dayton DC-160-4 drivers - 1 per enclosure. Net result - very pleased.

Each enclosure is approximately 32.5 cm x 20cm x 20cm. Front baffle 18mm, the remainder being 12mm MDF. All joins are sealed, side panels fitted with Silent Coat automotive sound deadening and what I call a T-brace fitted. Woofers mounted at one end to allow for different positioning options.

I originally tried them full range - pretty good but with obvious treble roll-off. I then trialled them in the bedroom system (Arcam Movie 2.1/Piega TS3 speakers) with the Arcam’s internal crossover set at 60hz. Power was provided by a 20 WPC Temple Audio Bantam Stealth (great little power amp) and each ‘bass module’ was positioned near its corresponding main speaker. The best result I found was to be upward firing. Integration was very straightforward - no boom whatsoever. Just smoothly integrated bass that supported the main speakers and made them sound considerably larger/full bodied than they were originally - the Piegas are surprisingly able for their size anyway.

The above results were so good that I am now contemplating building something else for the office (and finding something suitable with an adjustable lpf to power it) and keeping these for the bedroom. The advantage of being small, light and passive is that they can be unplugged and stored away when not being used. The total build cost was about £80 for the pair including £20 per woofer, £30 of MDF and about £10 for sundries, including cables and speakers terminals. The paint and other bits I already had in.

I would upload pictures but I cannot see any easy way to do it.
 
Sounds (?) like you got it sorted Alex. For the low entry point of that series of driver I have been very pleased with the both the quantity and quality of bass output. Enjoy.
Karl
(Go to Manage Attachments in the Additional Options box and insert photo file name(s) in pop-up window and hit Upload. As they told us in school: "Show your work.")
 
Thanks for the info ref uploading pictures.

I have attached pictures of the ‘build process’. In the end I purchased a Nobsound (my wife finds the brand name amusing) G2 subwoofer amplifier and I am currently trialling it with just one subwoofer. TBH in the office the combination provides plenty of output. The amplifier is supposed to be 2 ohm stable (unlike the more powerful G2 pro version) and has a 40 - 300 hz LPF, though there are no increments marked - I have largely tuned it by ear using an educated guess of where the frequency is on the dial. I am gradually turning the volume down which in my experience is always a good sign! The amp has selectable gain settings on the bottom through dip switches - I am using the factory-set 26 db option as the desk amp (see below) has quite a high output through the subwoofer output.

The rest of the office system consists of:
Tibo Bond 3 streamer / Arcam Alpha 5 CDP
AVA Media Maestro 50 fully digital amplifier - no analogue inputs.
Mission 731i speakers
Sometimes I swap the AVA with an Arcam A18 if I want a bit more power - obviously an all analogue amplifier. They both have their own merits.

Regards
Alex

Sorry that one of the pictures is upside down - I’m not sure how to change this.
 

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The one thing I’m not so happy about is the paint finish. I contemplated spraying the boxes but, bearing in mind their intended use where they could get kicked and knocked by the office chair, I thought a durable and easy to touch-up finish would be best. I used a paint that has proved itself on our kitchen cabinets and a roller to apply it. I like the colour but would have preferred it slightly smoother. Still, as a first build I’m happy.