Author Topic: New Bookshelf Speakers  (Read 2001 times)

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Offline LooseSox

  • Posts: 89
New Bookshelf Speakers
« on: November 12, 2017, 07:14 AM »
Well it's been a while since I've built my last set of speakers and almost as long since I've built any for a customer too. I recently came across some spare tweeters from my surround sound build (spousal approval could only be had for a 5.1 system, 7.2 got a big no). Seeing as I had these plus some random crossover components I decided to get some woofers and the rest of the parts and get building a set of bookshelf speakers.

This build was a series of firsts for me using a few techniques I've never done before. Usually I use pre veneered mdf for my builds. This time I used plain mdf and veneered it myself (never done my own veneer without an industrial vacuum bag press) as I'd recently been given some nice Jarrah veneer.

I went with a sprayed satin black front baffle which I'd never done before either, 1 because I didn't have enough veneer to do all 6 sides of the box and 2 wifey wasn't keen on the cost of me doing the fronts in carbon fibre (regardless of the fact they'd then be the coolest speakers ever!).

Next on the never been done before list was the finish. I usually spray poly or 2k clear but this time went for French Polish. I've always wanted to try it out but never had a need for it so I thought this was the go. They got 12 coats then a rub back with 1200 paper then some wax to knock back the gloss a bit. Please ignore the blob of wax in the grain in one of the pics. I only just noticed that myself looking at the pic, the flash picked up what I couldn't see in the shed so I'll re buff that side tomorrow.

Now the woodwork side of it is out of the way I'll ramble on about the electrics as there are a few speaker buffs here. The woofers and tweeters are Peerless. The box is rear ported with an internal volume of 7.7L, a sheet of dampening material was applied to the inner back wall of the box too. For the eagle eyes out there, yes the tweeter is deliberately connected out of phase.

I've only just begun the break in process and have already been impressed with their ability with rock and blues so all in all quite happy with the finished result.
« Last Edit: November 12, 2017, 07:20 AM by LooseSox »

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Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #1 on: November 12, 2017, 07:18 AM »
Also pay no attention to the mess in the workshop! I'm also in the process of building a huge subwoofer for a freind (680L box!) so everything has been thrown down the front of the workshop so I've got room to work up the back. You can usually see half my workbech lol

Offline antss

  • Posts: 1374
Re: New Bookshelf Speakers
« Reply #2 on: November 12, 2017, 11:40 AM »
Very nice casework.

Why did you chose a ported design for such a small speaker ?   Were you trying to lower the bass extension to mesh with an existing sub ?

Offline Cheese

  • Posts: 3609
Re: New Bookshelf Speakers
« Reply #3 on: November 12, 2017, 12:33 PM »
Nice stuff...

I especially like the matching of the veneer from the side to the top of the speaker. [thumbs up]

Some questions:

How are the boxes constructed?
Why a rear vented enclosure?
Is the rear wall dampening material the only dampening material in the enclosure? Any cabinet resonance?
Who makes the crossover components?
The 12 coats you mentioned are 12 coats of what?

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #4 on: November 12, 2017, 02:55 PM »
Thanks guys.

@antss the woofers 'optimal' enclosure size is 34L but has a flat response in a box all the way down to 5ishL. I went ported to give a bit more bass extension that it otherwise would have in a sealed box.

@Cheese the mdf panels are held together with rebated butt joints. This leaves exposed edges of mdf but when veneering after this didnt matter. When I use pre veneered panels, its just 45 degree mitres and glue as anything else would mess up the corners. I used 18mm mdf so resonance isn't an issue in a box that size. Any bigger and I would have used some bracing. One sheet of dampening along the back wall is all there is, it's enough for what it needs to do in that box.

12 coats of finish, being the French polish/shellac/whatever you want to call it. I used a premix as I wasn't keen on mixing it from flakes for my first shot at it but thinned it down a bit so it went on easier hence more coats.

Box is rear vented for a few reasons, 1 it wouldn't fit on the front baffle without increasing the over all box size. 2 I prefer the cleaner look of no front porting. 3 you get slightly better bass response from a rear port, at the expense of placement options as the box now has to sit further out from a wall than it would have with a front port.

Crossover components, what exactly did you mean? Manufacturer of the individual parts? I couldn't tell you them all to be honest. I've found a local supplier that sells me the parts at a discount to rrp and I'm happy with their performance so I just go with that. As for the assembly of the crossover, I soldered it all up myself, in the kitchen when my wife was at the shops so I could get out of the heat of the workshop. Glad I had that all cleaned up before she got home LOL.

Offline bigchas

  • Posts: 313
Re: New Bookshelf Speakers
« Reply #5 on: November 12, 2017, 05:27 PM »
Very nice. I have a speaker cabinet project on my wish list. I have a set of tannoy 605s and would like to make new cabinets for them but I'm nervous about how a new enclosure might colour the sound. any opinion/science welcome?

Offline duburban

  • Posts: 901
Re: New Bookshelf Speakers
« Reply #6 on: November 12, 2017, 07:30 PM »
where did you gain the knowledge for design of these speakers? i really want to do this...
helper: i used a festool "circular saw" to do something simple and it made it really hard

me: exactly, it makes simple cuts complicated and complicated cuts simple

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #7 on: November 12, 2017, 08:45 PM »
Very nice. I have a speaker cabinet project on my wish list. I have a set of tannoy 605s and would like to make new cabinets for them but I'm nervous about how a new enclosure might colour the sound. any opinion/science welcome?

Keep the internal volume of the box the same as the original. Same for port length and diameter if there is one. Altering the box volume will require tweaking of the crossover.

Offline Cheese

  • Posts: 3609
Re: New Bookshelf Speakers
« Reply #8 on: November 12, 2017, 08:47 PM »
Thanks for the update. I assume Peerless provides the crossover frequencies, do they also provide the frequency attenuation rate?

Is there literature available that would help others design their own crossovers and choose the correct components?

I harken back to the JBL, Voice of the Theatre, Klipschorn era when you built speaker enclosures based on the manufacturers empirical data and then purchased/incorporated their proprietary crossovers into the speaker cab. It was expensive but back then everything was expensive.

I’d certainly entertain an ongoing weekly/monthly tutorial on current speaker design. A lot of things have changed over the last 50 years in speaker manufacturing...in woodworking not so much. It’s still just a sharp steel edge against a wooden surface.   [tongue]

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #9 on: November 12, 2017, 08:58 PM »
where did you gain the knowledge for design of these speakers? i really want to do this...

Picked it up over the past 20 years by combining my loves of woodwork and electronics. A mate's mum went to med school with Scott Krix of Krix Audio before he dropped out to do engineering so got me in touch with him and passed on some serious knowledge too. Plenty of diy audio forums about the place that will give you plenty of advice to get you on your way, that's what really got me into it.

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #10 on: November 12, 2017, 09:10 PM »
Cheese, crossover design is somewhat akin to the dark arts! Knowing when the woofer drops off is just one thing. Crossover design will alter based on that, box size, typical music played and personal preference. I still struggle with it from time to time on more complex builds, thankfully my best friend is an electronic engineer and is quite happy to help out when I get stuck.

Yes you can buy of the shelf crossovers for 2.8khz, 3.5khz, 5khz etc etc but they are VERY basic and solely split the frequencies between woofer and tweeter. They don't take into account time alignments, box nuances, cone break up, also driver impedance will change based on frequency so you can dial out peaks in response at certain frequencies with extra resistors.

No one really provides crossover point or attenuation slopes. It's such a personal preference and a variable based on what you want to achieve and the components you're working with. Manufacturers will supply frequency response graphs that will give an idea as to whether 2 drivers will work well together, eg you dont want to use a woofer that drops off dramatically after 1500hz with a tweether that doesn't play well below 2000hz or you'll end up with a big dead zone.

Manufacturers will provide the drivers T/S parameters which can be used with modelling software to render response graphs from different enclosure and crossover designs.

Offline Cheese

  • Posts: 3609
Re: New Bookshelf Speakers
« Reply #11 on: November 13, 2017, 03:16 AM »
So you’re saying that while the times have changed, the voodoo hasn’t.  [eek]

I guess you just eloquently stated the reason, in a round about fashion, why I always purchased the factory crossovers and simply installed them in the speaker cabinets. No garlic, no stake through the heart ❤️ , just a simple pay your money and take your ride process.

I’m also used to the old school method of having anechoic chambers being one of the final arbiters on audio performance. The new audio evaluation methodology appears to employ utilizing microphones in a near field position.

As far as I’m concerned, the crossovers are really the “come to Jesus” issue in speaker design.

Also of interest to me is the current trend of utilizing multiple small woofers instead of a single large woofer. Time was when no self respecting speaker system would employ anything less than a 12” woofer...a 14” was better and an 18” was better yet. Now it’s populated mostly by multiple 6” & 8” woofers.

Just random thoughts...while listening to Freddie Mercury.
« Last Edit: November 13, 2017, 03:26 AM by Cheese »

Offline Bohdan

  • Posts: 791
Re: New Bookshelf Speakers
« Reply #12 on: November 13, 2017, 03:38 AM »
Years ago I was mass producing a 2 cub ft speaker with 2 x 8" woofers which easily out performed an equivalent 12" woofer model in quantity and quality of bass but because of their higher resonance frequency they cut out a little earlier on the bottom end. They actually sounded better with a cleaner bass but the public prefered the 12" model because the specs showed that the 12" woofer would go just a little bit lower.

I personally chose a Crown (ES212) system with 2 x 10" woofers with electrostatic tweeters because when I evaluated them I found that for the first time I was listening to the music and not the speakers.

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #13 on: November 13, 2017, 04:53 AM »
Don't go near the anechoic chamber argument! Unless you get to listen to your speakers in one daily then how they perform in one is ultimately irrelevant. Likewise, people like to reference specific 'typical' test tracks, Brothers in Arms, the 1812, etc. Unless you listen to that regularly then once again it doesn't matter. If you're listening to queen, find something that plays old school rock well and be happy.
« Last Edit: November 13, 2017, 05:00 AM by LooseSox »

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #14 on: November 13, 2017, 05:06 AM »
@Bohdan that sounds interesting. How long ago were you doing this? Were you making sealed, ported transmission line?

Offline Bohdan

  • Posts: 791
Re: New Bookshelf Speakers
« Reply #15 on: November 13, 2017, 08:01 AM »
Started designing and building speakers in the 60s. Made well known name brand speaker boxes for some of the importers and designed house brands for most of the bigger retail hifi stores.

Built mostly bass reflex (both front and rear), sealed, some horn loaded (both front and rear), not many transmission lines. Quite a few big PA/guitar speakers, biggest bass guitar set was horn loaded with an 8' mouth and designed to collapse so it could be transported. Most bass players that tried it didn't like it because if they hit a wrong note everybody noticed.

Finished up mid 70s when I decided that having my designs ripped off and used to undercut me had no future so I joined the education system for the next 30 odd years.

Offline Cheese

  • Posts: 3609
Re: New Bookshelf Speakers
« Reply #16 on: November 13, 2017, 09:44 AM »
I personally chose a Crown (ES212) system with 2 x 10" woofers with electrostatic tweeters because when I evaluated them I found that for the first time I was listening to the music and not the speakers.

That's interesting...didn't know Crown produced speaker systems. I'm only familiar with their electronics, because I owned some. When did Crown produce speaker systems?

Offline mike_aa

  • Posts: 980
Re: New Bookshelf Speakers
« Reply #17 on: November 13, 2017, 12:55 PM »
@LooseSox  These look great!  The fit and finish on the veneer and paint are top notch.  I've always had a great deal of respect for those who have the knowledge to be able to assemble a speaker/crossover/box package from scratch.  Thank you for sharing!

For people like me who can solder, but don't have a clue on how to pick out components, I found a speaker kit online for not a lot of money.  Not sure how good these are, but they might be fun to build.

Mike A.


Offline VW MICK

  • Posts: 855
Re: New Bookshelf Speakers
« Reply #18 on: November 13, 2017, 01:57 PM »
@LooseSox  These look great!  The fit and finish on the veneer and paint are top notch.  I've always had a great deal of respect for those who have the knowledge to be able to assemble a speaker/crossover/box package from scratch.  Thank you for sharing!

For people like me who can solder, but don't have a clue on how to pick out components, I found a speaker kit online for not a lot of money.  Not sure how good these are, but they might be fun to build.

Yes I agree I would love to do this but it seems a bit complicated

Mike A.



Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #19 on: November 13, 2017, 02:23 PM »
Those kits are pretty decent from what I've read. I was thinking of getting a few kits for a surround system for my sister's new house, but as per usual, frieght to Australia kills it. I even asked if they could take the cabinet parts out and just post the electrics but that seemed like too much effort for them :/

As long as you know how to solder, that kit will basically fall together. The manual is online, have a look at it, there isn't much involved to end up with a decent pair of speakers.

Offline bnaboatbuilder

  • Posts: 88
Re: New Bookshelf Speakers
« Reply #20 on: November 13, 2017, 05:18 PM »
Just a bought a set from your link. I'd been wanting to build some small speakers.

When I was in high school (30 yrs ago), built 2 sets of B.A.S (big  speakers) because those were cool back then. Freshman year in college I built a pair for a classmate for good money.

Now I'm more into smaller speakers and had been wanting to do this. So much time has passed, I wouldn't have a clue what to buy if parting it out the way I did back then. Funny enough, I bought my stuff from Parts Express back then.

@LooseSox  These look great!  The fit and finish on the veneer and paint are top notch.  I've always had a great deal of respect for those who have the knowledge to be able to assemble a speaker/crossover/box package from scratch.  Thank you for sharing!

For people like me who can solder, but don't have a clue on how to pick out components, I found a speaker kit online for not a lot of money.  Not sure how good these are, but they might be fun to build.

Mike A.
- John

Offline Bohdan

  • Posts: 791
Re: New Bookshelf Speakers
« Reply #21 on: November 13, 2017, 07:34 PM »
...When did Crown produce speaker systems?

IIRC Crown speakers were only produced for a short time around the middle to late 70s.

Offline Cheese

  • Posts: 3609
Re: New Bookshelf Speakers
« Reply #22 on: November 13, 2017, 09:43 PM »
IIRC Crown speakers were only produced for a short time around the middle to late 70s.

That’s very interesting, the Crown electronics were superb considering their price point, and their reel-to-reel tape recorders were the best of the best. A close second was Revox.
They were truly state of the art at that time. And I may add, bulletproof. There’s a reason why Jethro Tull and Led Zeppelin used them exclusively for concerts.

Offline Holmz

  • Posts: 3987
Re: New Bookshelf Speakers
« Reply #23 on: November 17, 2017, 03:02 PM »
@LooseSox what do you think about miniDSP and things like the DIRAC, and then bi/tri-amping to remove the cross overs and fix all the EQ, time-alignment and phase issues?

Then there are a few decent op-amp based amplifier designs in the 30-70W range with decent THD+N figures that could used...

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #24 on: November 17, 2017, 03:53 PM »
@Holmz that really depends on how far down the rabbit hole you want to go! I've never really got into it much myself as I never could justify the expense of doing it plus I've always been happy with a passive setup in terms of sound quality.

You'd want to have some very good quality drivers in the build as I doubt you'd make an audible (to the human ear anyway) differnece in the average living room. Throw in a few diffusers and bass traps around the room and then you'll really hear a change. In my experience, active gear won't make as big a change over passive gear vs passive gear in an optimised room environment.

Offline Holmz

  • Posts: 3987
Re: New Bookshelf Speakers
« Reply #25 on: November 17, 2017, 04:09 PM »
Understood... I keep coming back to the woofers and subwoofers using the majority of the power, and the low notes being a good candidate for modern class-D amplifiers, and the higher notes being potentially better served with class-AB or Class-A. Whether than is just an active cross over, or a DSP...

I need to shoot over to get some terminal strips and maybe figure out a box for holding the amps for a vehicle install. I had wires strewn over the table last weekend with a car battery and it was a total mess. Got some sound thinly coming over some ribbon tweeters, and had some VU meters in parallel. I should have removed those, but did not think about at the time. Then the power went off on both Sunday and Monday with the storms, so it was like we were spiritually in SA...

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #26 on: November 17, 2017, 05:14 PM »
And we managed to keep the lights on here during the ratty weather last week! lol

Subwoofers is really where DSP will get the most bang for your buck in a home setup. A car even more so. The wave length of sub bass frequencies are huge and can cause all kinds of issues when setting up a susyem, especially if the sub is in a fixed location and can't really be moved (eg in boot of car, or corner of lounge room).

Offline Holmz

  • Posts: 3987
Re: New Bookshelf Speakers
« Reply #27 on: November 17, 2017, 05:42 PM »
Need to order the Nuetrik speakon connectors, as I already have holes in the speaker boxes for them and I ordered a 100 pack of M3 screws and locknuts...

The connectors seem pretty schmicko, and the mogami 4-core 11ga wire is relatively cheap and not too difficult to make up.

Offline LooseSox

  • Posts: 89
Re: New Bookshelf Speakers
« Reply #28 on: November 20, 2017, 02:34 PM »
Well then, the recent warm spell here (mid 30sC) has bought on a couple of small bubbles in the veneer  >:(

And of course, not on the back, but on the top of the bixes! I'm going to have a go at fixing it, but I have a feeling I didn't use enough epoxy all over considering the thirsty nature of mdf. I'm also in the process of building another set with silky oak veneer but this time I'm using the pva iron on technique.