HIFICRITIC audio review magazine
HIFICRITIC FORUMS
New Issue: Vol 7, No 1
HIFICRITIC
Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error
7 Pages«<34567>
HIFICRITIC DIY speaker - Martin Colloms
Share Options Go to last post Go to first unread
Previous Topic Next Topic
Martin Colloms Offline
#81 Posted : 06 February 2011 17:43:16(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
some news

primary electroacoustic modelling done

enclosures designed and drawn up in full ready for prototyping

first part feature article under way for issue vol 5 no 1

Substantive system design during March -April

Final part of DIY feature vol 5 no 2 April-June issue

MartinC
Back to top
darkmatter Offline
#82 Posted : 06 February 2011 18:10:51(UTC)
Retweet
darkmatter


Rank: Administrator

Joined: 19/09/2008(UTC)
Posts: 1,667
United Kingdom
Location: UK

Thanks: 8 times
Was thanked: 5 time(s) in 5 post(s)
Look forward to that :)
Back to top
Twitter
Martin Colloms Offline
#83 Posted : 23 February 2011 13:38:20(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
Based on early estimates we think the kit will cost between £850 and £1250 a pair depending on how much you build, the higher price is for cabinets which are factory built and finished, though you will still have to install the drivers and stuff.

MartinC
Back to top
darkmatter Offline
#84 Posted : 23 February 2011 13:44:20(UTC)
Retweet
darkmatter


Rank: Administrator

Joined: 19/09/2008(UTC)
Posts: 1,667
United Kingdom
Location: UK

Thanks: 8 times
Was thanked: 5 time(s) in 5 post(s)
Will the crossovers be pre-built or will the more adventurous be able to make them up from scratch?
Back to top
Twitter
Martin Colloms Offline
#85 Posted : 20 March 2011 15:00:39(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
The crossovers will be remote , on the deck near the speakers

Much scope for customisation, and there will be a standard CX built on a PCB , plus a kit , or grow your own.

Chuck the crossover and you can easily go active , we will publish the required terminal frequency responses at the drivers

we will show pictures and quite a lot of detail in the upcoming issue.

Martin Colloms

Back to top
rosie Offline
#86 Posted : 02 April 2011 13:53:43(UTC)
Retweet
rosie


Rank: HIFI Newbie

Joined: 19/10/2010(UTC)
Posts: 4
Location: where even the grass is blue
Just ordered vol 5.1 TRK Could be just what I am looking for, lets hope. Will Wimslow have it on dem?

rosie
Back to top
Martin Colloms Offline
#87 Posted : 03 April 2011 13:33:46(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
I should think so once designed and approved , a few months yet

we are thinking about running it at NAS!

Martin Colloms
Back to top
rosie Offline
#88 Posted : 03 April 2011 16:51:56(UTC)
Retweet
rosie


Rank: HIFI Newbie

Joined: 19/10/2010(UTC)
Posts: 4
Location: where even the grass is blue
See you at NAS then

Regards rosie
Back to top
ashleym Offline
#89 Posted : 10 April 2011 00:00:46(UTC)
Retweet
ashleym


Rank: HIFI Veteran

Joined: 02/02/2009(UTC)
Posts: 901
Location: uk

Thanks: 1 times
Was thanked: 2 time(s) in 2 post(s)
I've got the new issue. It answers a few more questions. I was afraid of a metal cone bass drivers because of the cone misbehaviour (my AE1's have all sorts of stuff in the way of the signal to deal with these) but I now see that with the early roll off you can notch out the nasties.

Looking ever more interesting. However, just like when you speak to someone on the phone and then meet them the design was a surprise. I didnt expect TRKs to be floor standers, I was expecting a Snell E type shape.
Back to top
Martin Colloms Offline
#90 Posted : 10 April 2011 10:54:49(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
Just a note

the BMR is intrinsically full range and the opportunity to use a lower crossover frequency helps deal with the bass cone issues.

There won't be any cone type breakup colouration from the main driver. An awful lot of music happens from 50Hz to 800Hz

Think of top C for a soprano.

we will have to voice the 50 to 800Hz range very carefully

Martin Colloms
Back to top
Martin Colloms Offline
#91 Posted : 14 May 2011 17:00:27(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
Some news , the first phase is done and reported in depth in print, Vol 5 , no 1 ,

we have stuff in , everything fits nicely and the prototyping on the built systems is beginning now. The Wilmslow cabinets are fine , heavy, and very strong .

It will not be ready for Vol 5 issue 2 , it will be Vol 5 issue 3 July-September when will have the low down ready for the NAS show in late September.

Anything interesting we will report on this forum

Martin Colloms
Back to top
Martin Colloms Offline
#92 Posted : 20 May 2011 13:38:54(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
With the arrival of the DNM Precision wiring looms Chris Ellis, co-designer got stuck in straight away using his 'first trials' technique involving quad power amps, and a multi channel DSP card , USB controlled.

Available software allows Chris to configure the four section crossover as a series of connected bricks, on screen and these may be tried out ,measured, adjusting the slopes, phase , level and micro tuning and comparing these variations more or less on the fly.

Early results are in giving us significant encouragement

The bass times well and is powerful and quick and seems almost perfectly matched to the tuned, mid treble loudness level.

The BMR is as expected is not optimal straight out of the box, but seems readily amenable to modest micro tuning in the crossover

Early trials suggest that a really low crossover frequency frequency is possible , 300-330 Hz, meaning that the BMR is working linear phase 'single driver' over the bulk of the audio bandwidth. The big SEAS driver proves to be extremely neutral in the 30 to 350Hz range.

We are going to meet the 86dB sensitivity and easy drive 6-8ohm rated impedance targets.

In the flesh TRK is quite an imposing and stately example, nothing undersized or amateur about it !

Once the first trial crossover curves are settled Chris will synthesize the passive crossover equivalents , having also modelled the complex electrical termination provided by each driver in situ in the enclosure.

Once the passives are built these will be subject to exhaustive trial and adjustment to optimise the overall result.

Martin Colloms

Edited by user 30 September 2011 12:55:44(UTC)  | Reason: Not specified
Back to top
Martin Colloms Offline
#93 Posted : 27 May 2011 19:12:16(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)



TRK Progress

First passive component synthesis done, looks a good match on paper

components ordered, plus variations on the theme, for voicing

One issue is choosing components which are consonant with the kit price from our chosen whole kit supplier Wilmslow Audio .

Builders may choose more costly parts if they wish, full specifications will be provided and the circuit will be compatible with a variety of component types and qualities

Some 'audiophile' bits can be shockingly expensive . e.g. £35 for a one off retail 5uF capacitor.

To begin we are avoiding the specials and looking to see what can be done with the more usual manufacturers parts for this quality range of speaker

If the top kit price is say £1,2oo per pair with pre built cabinets supplied , and if good enough , retail would have been about £ £2,800 a pair.

These do not get many M Cap Supremes in my experience, but feel free to fit them.

Martin Colloms

Edited by user 01 June 2011 08:54:58(UTC)  | Reason: Not specified
Back to top
ashleym Offline
#94 Posted : 31 May 2011 14:06:13(UTC)
Retweet
ashleym


Rank: HIFI Veteran

Joined: 02/02/2009(UTC)
Posts: 901
Location: uk

Thanks: 1 times
Was thanked: 2 time(s) in 2 post(s)
I agree that we can wait until TRK is released into the world before worrying about eye wateringly expensive parts. The right part in the right place can work well, ie real world priced speakers. It will make the speaker stand out if we (you?) can get exceptional results without breaking the bank and using correct design rather than being swamped by "magic" components.

The ES14s are looking at me worriedly. The new to me SBLs are on hold.
Back to top
Martin Colloms Offline
#95 Posted : 18 July 2011 12:45:24(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
just some interim news

Christien Ellis (CE Elctroacoustics) and I did the transfer from the active , auditioned synthesis to Wilmslow component passive crossovers last week and I brought them back to base in London

Inevitably some fine tuning was required while the BMR also responded to some revised network topology.

We are on target with an 86.5dB/W sensitivity and a 33Hz in-room response at respectable power, but the impedance is lower that I aimed for:
nominally 6ohm with 4.5ohm minimae, not so easy for valve amps after all except with 4 ohm output taps.

The sound is most promising particularly in respect of timing, and I am getting some second opinions on it so there is an independent view of its performance.

While the Cotswold BMR is not the smoothest measuring of drivers it does sound coherent and well integrated the trend can be coaxed into shape for a relatively neutral tonal balance
and pleasing sound stage perspectives.

A rewarding feature is the seamless crossover transition at the now defined 310Hz frequency, matched for the floor and wall boundary, delivering robust bass transients and fine bass tune playing.

Much more to do on documentation etc

Martin Colloms

Edited by user 18 July 2011 17:09:07(UTC)  | Reason: Not specified
Back to top
ashleym Offline
#96 Posted : 18 July 2011 22:51:21(UTC)
Retweet
ashleym


Rank: HIFI Veteran

Joined: 02/02/2009(UTC)
Posts: 901
Location: uk

Thanks: 1 times
Was thanked: 2 time(s) in 2 post(s)
I dont think the Fujitsu Eclipse having a slightly ragged frequency response has dampened (sorry) the enthusiasm of people who "get" them. So I dont think a little character in the response of the BMR will harm them either. Although I do understand that you will be sorting out their worst excess's. Hopefully the BMR's better off axis response will help them sound great too.
Back to top
Martin Colloms Offline
#97 Posted : 31 July 2011 11:23:59(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
If all goes to plan we will have a dem room at NAS for The Rhythm King

It is now prototyped in standard passive form.

Several independent ears have auditioned it and it is now signed off

DNM and Wilmslow Audio will also be present to help with queries

We will do talks on the theory and design of this unusual loudspeaker.

The co-designers, Christien Ellis and Miles O'Caroll will also attend.


Martin Colloms
Back to top
Matt Offline
#98 Posted : 05 August 2011 12:18:19(UTC)
Retweet
Matt


Rank: HIFI Addict

Joined: 08/12/2009(UTC)
Posts: 95

Thanks: 1 times
Will the speaker kit be supplied with DNM internal wiring?

Edited by user 24 August 2011 17:12:47(UTC)  | Reason: Not specified
Back to top
Martin Colloms Offline
#99 Posted : 10 August 2011 14:47:25(UTC)
Retweet
Martin Colloms


Rank: Administrator

Joined: 15/07/2008(UTC)
Posts: 1,842

Was thanked: 8 time(s) in 8 post(s)
DNM wiring is in the specification

Martin C
Back to top
Shadders Offline
#100 Posted : 18 August 2011 22:37:51(UTC)
Retweet
Shadders


Rank: HIFI Addict

Joined: 07/04/2010(UTC)
Posts: 170
Location: UK
I have and i am still using the Richard MacDonald large transmission line speakers from 1993 Hifi News article - Wilmslow Audio kit.

How will the TRK speakers compare to this design - i know there is no definitive answer - but what changes in sound should i expect - less tight bass, more refined top end (TLine speakers have metal dome tweeters), smooth mid-band due to the BMR, but less high frequency content etc.

Thanks in advance.

Shadders.

Edited by user 18 August 2011 22:38:51(UTC)  | Reason: Not specified
Back to top
Users browsing this topic
Guest
7 Pages«<34567>
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Powered by YAF | YAF © 2003-2013, Yet Another Forum.NET