Improving speakers (to your own individual circumstances)

Hi-Fi Corner
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Speaker manufacturers have their own ideas on what is ‘the best sound’ but the can never make anything that will fit all. There are just too many unknown factors involved. If it is a budget speaker, build constraints will be more significant but even higher end speakers, in their original form, may not fit your home perfectly. There could be many reasons for this regardless of how much care the manufacturer has put in it. The room can play havoc with sound as we all know. You may have tried room treatment but not everyone can or wants to do this. You have DSP/EQ and it works to an extent but has not fully solved the issue or perhaps there is simply a niggling doubt about a certain aspect of a particular speaker which no available adjustments can get 100% right.

Have you altered your speakers? Short of building your own pair that may be the answer and it can be surprisingly easy to do so.

I have had several speakers which I liked greatly but thought I could improve further upon; My beloved ancient Mission 752 Freedom’s are known to have an internal standing wave issue. I got around this by placing 10cm polystyrene balls, halved, up and down the column. I also added a couple of cross braces. They also initially seemed to have some internal sound reflecting back through the driver so I placed absorption right behind the driver. I changed the ferrofluid too though that was not strictly necessary and made the smallest difference.

My latest stand mounts have a tight and fast sound, image well and have good timbre but had a what I thought very slight hollowness to their sound. I made an absorption pad and used velcro to attach this on the magnet of the main driver. Whilst I had them out I also fitted some damping pads on the driver basket riggers. Worked great.

Similar with a tiny pair of toddler speakers from Denon/Mission. Great things but a slight hollow sound. Added a bit of absorbent material behind the drivers … solved.

You could rewire your speakers or simply remove the connectors used by the manufacturer to connect the wiring to the drivers and solder them instead. I have done this in the past but not on my current speakers

Everything is easily reversible, does not take long. I made mistakes along the way. With one speaker I used a filling material recommended by many builders as the ‘best’. I tried every quantity possible, never finding one that worked. Apart from making a huge mess, it was a waste of time but other than time and very little cost, nothing lost, something learned.

Have you altered yours?

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Way back in the past, we’re talking about getting on for 50 years ago now, I modified my pair of KEF Coda II speakers after reading an article by a certain reviewer in Hi-Fi Answers. This particular reviewer (anyone familiar with those times will probably know who I mean) was renowned for experimentation, some of it quite bizarre, and had a bee in his bonnet about speakers sounding much better with any internal wadding removed and with the drivers bolted to the cabinets instead of the small woodscrews typical of the time.

So I removed the internal wadding and replaced the small wood screws holding the drivers to the baffle with substantial bolts / nuts done up very tightly. Which wasn’t an easy job. Result - total disaster. They now sounded more immediate/dynamic and authoritative for sure but also horribly coloured. After that I would never attempt anything like it again.

My own opinion now is that it isn’t sensible to mess with a design. Any design involves compromises and trade-offs which the designer has engineered to make a balanced sounding product. Altering anything will change the sound and may indeed improve performance in some respects but IMO will more than likely result in an overall performance that is less satisfactory. If it were so simple to get a better performance from the product then why wouldn’t the manufacturer have made it like that in the first place?

Of course that’s not quite the same as saying you won’t prefer it modified. It may be more to your own personal taste and if so that’s fine.

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I’ve a pair of IBL’ and an IXO. I’ve a long term consideration to build some class-d amp packs for them and drive them active. I know how they sound active and that’s quite a bit better than passive.

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Because they can’t possibly foresee every usage scenario/equipment match, room or even taste.

The only speaker that is ‘perfect’ is a high quality, active near field monitor that uses the best ingredients, leaves the room out of the equation and measures perfect. We all know that doesn’t necessarily equate to listening pleasure.

If you are entirely happy with your sound, there is obviously no need to tamper with the product.

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In general I feel it is better to buy decent speakers with minimal compromises and just use them. The obvious alternative for anyone reasonably good at DIY constructionis to build one’s own, though for true success that means either having a proven design that has been verified to do exactly what it’s supposed to, or having the ability, time and test equipment necessary for developing something good from scratch.

In terms of modifying an existing speaker, I have done that once: the speakers were very good (PMC EB1i), however their midrange was not as good as the best speaker I had ever heard (PMC MB2). Simply replacing the mid driver was not straightforward as aside from having to physically fit, they would undoubtedly need to be modifications to the crossover to balance it all correctly. However, happening to have an ATC SM75-150 3 inch dome tweeter which was widely regarded as one of the best mid range units ever made, and which PMC reputedly had cloned to create the unit used in the MB, and also happening to have a couple of active crossovers and spare power amps, I made a hybrid: I put each ATC mid unit and a tweeter in a small satellite box that I built, removed the crossover from the EB1, and used the EB1 purely for bass in a tri-amped set up. Tuning it all was facilitated using REW software and a measuring microphone. The result was a very good stand-in until I bought an MB2.

(Incidentally I was wholly unimpressed with some of the writings in hi-fi mags in the 70s and maybe early 80s, like stripping out acoustic linings that a manufacturer had painstakingly worked out what, where and how much made the speaker present music as close to neutrality as budget allowed, simply because the author had a differennt concept of what made music “exciting”. Might as well buy (or build) a more basic speaker without trying to make it neutral in the first place!

As for the idea of building from scratch, a few years ago I decided to have a go at building my own transmission line design (which is how I happened to have the ATC mid unit, also the tri-amping ability because that is so much easier to set up than it is design of a passive XO). First version was disappointing, and second one too! Back to the drawing board, literally, but that is when other things in my life became too busy to devote the time, and the project is on indefinite hold. One day when I have some spare time I may well have the impetus to pick us up again, when my aim would be to at least match the MB2. Whether that will ever happen is another matter, ssI hve no drive to improve what is already great, and and there is too much else to do!

Finally if you want to tune your speakers in the room, first thing to play with his position of speakers and listening seat, and indeed everything in the room: that can do a lot. Also acoustic treatment where it is feasible within the domestic environment. And also potentially use DSP to twealk. Some people tweak things by playing with speaker and interconnect cables, using them like some form of tone control.

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Yes. Even very experienced speaker designers with a wealth of experience and facilities at their disposal are unlikely to get it right without a number of attempts. What chance does an amateur have on their first or second attempt?! One of the reasons why it’s always seemed to me to be pointless to even try.

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I used passive IBL’s for around 17 years. I always dreamed of activating them but because of space constraints and room layout it just wasn’t possible to accommodate the extra electronics required. Then one thing and another happened in life and we ended up selling them. Superb speakers though and I always thought they sounded faster and more involving than SBL’s.

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You can, of course, buy a design of the shelf, even a kit of parts, simply requiring the necessary skills to assemble, that not being a difficult job for any DIYer. And there are others that are nearly complete: e.g. Wilmslow Audio do, or certainly did, a near clone of the PMCMB2 as a kit of parts. But, some of those parts are not exactly the same, such as using different even if nominally almost equivalent drivers, and, in particular IIRC, leaving it to the builder to decide exactly how they distribute the stuffing in the line (an essential component) – which is where the original PMC R&D will have spent a lot of time and effort, with much testing.

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I use GR Research No Rez sheets on my speakers, best and cheapest upgrade I’ve ever made.

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Try. You may be surprised :smiling_face_with_sunglasses:

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Yes I’m aware of the Wilmslow kits (didn’t realise they were still going!) and I did once (many years ago now) consider buying one. I don’t really have the necessary woodworking skills though to make a satisfactory job of it. You either do or you don’t. I just don’t and it would be botch up. A man has to know his limitations (as Dirty Harry, ie. Clint Eastwood once mused). For anyone with the capability though it can be a great way to get something really good that would otherwise be financially out of reach and also you get the satisfaction from building and finishing it yourself.

Building from a kit or even from a set of design instructions/plans is a very different proposition from designing your own speakers from scratch though.

Rather puts me in mind of when I was around 20 and my mate and I decided we wanted to have a remote control model aircraft to play with. We went to a model shop and bought a kit, believing we would have it assembled and flying within a few hours. On opening the box however, apart from there being no motor of any description or indeed radio control equipment, all the box contained was pieces of raw balsa wood and a set of plans for how to cut/machine it to shape and assemble the fashioned pieces! It went straight back.

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No, I haven’t altered my speakers. ATC know a lot more about speakers than I do. My current speakers have worked really well in two different rooms.
I wouldn’t mod my Naim electronics. Having heard more than a few LP12s that people have modified, I wouldn’t do that either.

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I have never modified shop bought speakers.
But I use custom speakers in the living room.

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Upon purchasing Neat floor standers with downwards facing isobarically arranged bass speakers for a carpeted room I placed them on slate chopping boards. My dealer originally thought they would make no difference but after placing the speakers on the slate and comparing the output declared that there was a big improvement.

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For modification imo the biggest problem is, I couldn’t perfectly pin point if the speaker really is the source issue in the chain, but when mod is done it’s done.

Before all the hard mods I will look at the setup. Like hollowed, harsh or bright could mostly point to source setup ime.

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In my last post I omitted to add that modifying a commercial speaker makes most sense on lower budget models. That is where the manufacturer inevitably will have committed less resources to construction, also design. As inferred by the OP, bracing flexing panels can be an easy job (depending on internal accessibility), likely to have positive effect …unless you like the added sound of the resonating panels! And of course you have free reign over how it is done - I once saw a pair where the owner had put a substantial steel threaded bar right through, with its ends and nuts on the outside of the enclosure! Also the crossover could be a limiting factor, especially with basic speakers, rebuilding or replacing being simple if you can solder.

For the avid DIYer, with availability of time and inclination to tweak, perhaps more than money to spend, it could be an interesting project/hobby, and I suggest that secondhand speakers could be a good source of starting point. However I also suggest that having suitable test equipment could be of benefit, enabling you to literally see how changes affect performance and from that more readily assess possible changes than may be practicable purely by ear, and certainly a lot quicker. I recommend REW software (free) combined with a measuring microphone i (REW’s recommendation of UMIK-1 is inexpensive and easily sold on if no longer wanted).

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