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Markaudio Designers and builders of audiophile grade drivers

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Old 8th May 2012, 09:35 AM   #21
Toppsy is offline Toppsy  United Kingdom
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pauldune wrote
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I would recommend caution, at 3.5 kHz the maximum power rating is way lower............
As Scott has replied technically perhaps, but the XO was originally designed for my Edingdale speakers and these were designed with low power SET amps in mind and have a 93/94dB efficiency. So power handling has not been an issue. They sound crap on high power chip amps and the like. I suppose they just show up the deficiencies of this type amp.

I could perhaps push the XO up to around 4kHz or a tad more for the Rossendales but initially I'll see how they sound at 3.5kHz using the existing XO but with a modified zobel. Again I shall be using a low power SET with these speakers. Though I have a Nelson Pass F5 to try out as well.
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Old 30th May 2012, 02:30 PM   #22
Toppsy is offline Toppsy  United Kingdom
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My planned work for Monday and yesterday to rewire a pair of speakers with silver wire and a few other mods I could not complete due to a lack of enough the silver wire so whilst awaiting delivery I was able to progress my Rossendale speakers. It's not until to have to do a rewire job like this you realise just how much length of wire goes into the hook-up wiring of my Edingdale speakers. I thought that 5m would suffice. I vastly underestimated and had to order another 5m role! That's nearly £100 just in silver hookup wire

Anyway back onto the Rossendale speakers.

One cabinet is completed in bare ply, with the other nearly 80% done. Should have that finished by tonight if it don't rain, with the drivers installed but not wired up. I am still awaiting delivery of the XO components that I expect won't now arrive until after the Jubilee Bank Holiday break.

I have attached a photo of the fully built speaker, alongside it's bigger brother to give perspective to their relative sizes. I like these, they are cute.

Not sure when I'll get he chance to wire them up fully as I've other committed builds before these. But I'll report back soon as they are running with an initial impression.

Click the image to open in full size. Click the image to open in full size.

The keen eyed of you will notice the Alpair12P gen2 paper cone driver inside it's shipping box and leaning up against the fire surround. These have now been running for around 20-hours and are improving all the time. Only another 180-odd hours to go, hey
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Old 5th June 2012, 07:05 PM   #23
Toppsy is offline Toppsy  United Kingdom
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My XO components were delivered Saturday morning and as rain had stopped play on some outdoor work I had planned I got straight on to building the crossover boards for the these, the Rossendale speakers.

I managed to complete them by early evening with a couple more hours work to install them and wire them up to the drivers on the Sunday. I resisted the temptation to listen critically to them as the drivers had not been run-in, but suffice to say they sounded fine which was an indication I had not wired them up wrongly. I had them hooked up to a Passlabs F5 amp and FM tuner and left them like that for the rest of the day.

I repeated this exercise Bank Holiday Monday. (Queen's Jubilee celebrations here in the UK). Today however, after the drivers had had some 20-hours play I decided to sit down for a critical listen.

In essence the goal of the design has been achieved. They are indeed a smaller version of the larger Edingdale speakers. As expected from a smaller box they don’t do the same dynamics as their larger cousins and they don’t go so low in the bass, but you’d expect that from the smaller speakers. One can’t defy the laws of physics.

Today I invited my mate Chris around for a critical appraisal as there were some points regards the speakers I wasn’t quite happy with. Chris felt the same when he listened. He commented they were missing something and lacked a certain involvement. He said he couldn’t get engaged with the overall sound. Chris then got up and said, let me try something, to which he turned down the adjustable L-Pad by 1½dB. This locked everything into place and suddenly Chris’s foot was tapping along to the music. Seems silly me had the L-pads set to -5½dB when they should have been set to -7dB. Can’t think why I had them set such, but no matter.

I then suggested I remove the speaker cloth I had placed over the port tube. I did this on the grounds of aesthetics, but foolishly it would appear. This gave us a small but significant increase in bass detail. Now the speakers were sounding rather good indeed. Things can only improve with more gradual break-in of the CHBW drivers. Scott says they need around 100-hours to fully free up which should result in a richer more detailed midrange. So these little speakers have great promise especially for smaller rooms where the larger Edingdales are perhaps too large or have too little WAF due to their size. These are small enough I can do flat pack kits as well as full builds, but the kits are going to need some thought of how best to do them. But for now I’ll leave them running for a few days to clock up the hours on the drivers and I need to get on with my other builds.

So I am sufficiently impressed to go the full hog with these and prep the cabinets ready for a piano black paint finish.
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Old 5th June 2012, 07:39 PM   #24
chrisb is offline chrisb  Canada
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couldn't resist rubbing our noses in it, could ya mate - "see my 12Ps in the break-in box?"
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Old 15th June 2012, 07:32 AM   #25
StevenZ is offline StevenZ  United States
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Very nice work Toppsy! Any more progress pics or impressions?
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Old 15th June 2012, 10:14 AM   #26
Toppsy is offline Toppsy  United Kingdom
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I’ve have only taken a few more photos, but here’s an outdoor shot taken in my back garden. I think this gives a better perspective of the proportions of the cute small floorstanders.

Click the image to open in full size.

These speakers are coming along very nicely. The drivers still need more hours to break-in fully but they give a similar detailed midrange as the W#6 if not quite the same richness. However, Mark tells me they will ‘sweeten up’ around the 200 to 300 hours mark so things can only improve further.

I'm still playing around with XO'vers at the moment as there is something I'm not quite happy with the 2nd order LR2 crossover that Scott designed with the cabinets. It may be the components and drivers need a lot more hours play but in comparison to the Edingdales there is some missing ‘air’ (call it presence if you like) and fine detail in the treble and upper mids that is very recessed and faint in the mix with this XO. Bass is also does not appear so tight. These are minor quibbles and to me manifests in a less involving/engaging a listen. Using the same XO as in my Edingdale speakers but changing the zobel values to suit the CHBW's this addresses those issues to my ears. However, here is the odd thing. After swapping over the crossovers I found I preferred the LR2 setup with SS amplification (Pass Labs F5) and not quite so good with my SE300b amps, whereas I found the reverse with the Edingdale XO.

So I have swapped out the original binding post tray for a bi-wire one and re-wired the speakers for external XO'vers. I'm just waiting on replacement zobel components to put back into the LR2 circuit boards before I can do direct A-B comparisons. Replacing the crossovers was a full evening’s work when they were inside the cabinets as space is rather limited. Having them both external will allow very quick swap-over’s so the memory effect of doing comparisons is minimised. When I get both XO boards fully populated I shall get my mate Chris around again as he has a more critical ear than me when it comes to comparing changes. I also need to touch base with Scottmoose for his opinions/observations on my findings to date and persuade him to come over to my place for his input.

However I have to say I am now getting good vibes from the sound these are producing and with some fine tuning of the crossovers they should be very good indeed.

Here’s a photo of the rear of the speakers with the new bi-wire inlay binding post tray and adjustable L-Pad. This latter item allows fine adjustment of the treble which on future builds can be replaced by a fixed resistor version as part of the XO boards.

Click the image to open in full size. Click the image to open in full size.
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Old 15th June 2012, 11:27 AM   #27
Toppsy is offline Toppsy  United Kingdom
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I do have to add that I believe this CHBW driver to be very good indeed and perhaps a little overlooked by the general DIY buying community. It's a pity there are so few designs out there specific to this driver. The likes of these Rossendale 2-way speakers are ideally suited to this driver when coupled to a tweeter of a quality and performance to compliment that of the CHBW's. Perhaps the CSS ERT26 or their new (though much more expensive) LD25X would make a rather nice bookshelf 2-way speaker.

I look forward with interest the 5 x CHBW + ERT26 design that I hope DaveD and Chrisby are progressing? If my experiences with these speakers is anything to go by they should excell in larger rooms where larger floorstanding speaker size in limited.
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Old 21st June 2012, 08:53 AM   #28
Toppsy is offline Toppsy  United Kingdom
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Well I finally got these sorted with the help of my mate Chris. I am really pleased how these have come out. Chris commented he thought them around 95% the performance of the larger Edingdales given the smaller size and hence not quite the same presence of sound as you expect from a smaller speaker.

In the end both Chris and I agreed the XO I use in the Edingdales with some small modification gives a far more involved a listen than the Linkwitz-Riley 2nd order.

Yesterday I drove over to a small one-man car repair/spray shop with the bare ply speakers. He quoted me £150 ($235US) do paint the speakers. Seems most the local taxi drivers around here recommend and use him so I'll give the work to him. If he does a good job then I'll recommend and use him again for any speakers with a paint finish.

His quoted price includes enough coats of 2-part high build primer with sanding down between coats in preparation for the black top coat and at least 3 finishing coats of laquer to achieve a piano black type finish. I just need to seal the ply with some sanding sealer.

I hope to get the bare cabinets to the painter early next week. He said it'll be a 3-day turn-around to do the job to allow natural drying/hardening of the paint layers, so I should get them back by the following weekend. I'll post up photos of the finished cabinets when I have them back.
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Old 16th July 2012, 11:33 AM   #29
Toppsy is offline Toppsy  United Kingdom
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Having just got back from a ‘boys’ weekend at up in Scotland at my mate Andrew’s I must say I was rather pleased how these speakers performed. Scottmoose was spot on with his description to me how he expected they would sound. Andrew and I also thought as did NickG, who also accompanied me for the weekend get together, that the little speakers coped very well indeed with some ‘torture’ tracks and sample ‘test’ pieces of music Nick had to hand. We also had some pink noise test tones downloaded on a portable hard disc that was interfaced with Andrew’s Squeezebox Touch player. This showed that the speakers were good to around 35Hz. Very creditable I thought for a small floor standing speaker. There also did not appear to be any dips or sags in the frequency sweep right up to 12kHz when I couldn’t hear anything after this, being close to retirement age. Andrew lost hearing around 14kHz as I think did Nick. So I call that a result. Not the loss of hearing at such frequencies you understand guys.

On another forum Andrew posted this comment:
Quote:
I just spent a very enjoyable weekend with these little floorstanders, to say I was floored by them would be an understatement, for the size they are excellent they have a dynamic and very balanced sound with a nice solid bass line under pinning the mix.
Well OK, so I suspect you are all expecting a photo of the Piano Black painted speakers. If so you’ll be disappointed somewhat as I was with the final results. Not a perfect ending and too boot with all the layers of paint that had been applied to get to that super gloss shine the bloody drivers wouldn’t fit into the rebated openings in the front baffle. ARRRRGGGHHH! At the end of the day the sprayer said he was not happy with the results as he had to rush it in the final stages. He said that having gone through the big learning curve with lessons learned with these original prototypes, he would do a perfect finish next time should I give him the chance. So I might just do that.

As mentioned, we went through a big learning curve with this experiment and now know the pitfalls to avoid and how to address them.

Lesson 1: Avoid any sharp corners. When buffing up the final lacquer coats to get that piano gloss look with a pro electric buffer and buffing cream, the circular buffing head digs a little deeper at these corners and so you can end up with the exposed grey primer in a few areas where the buffer was held in place for a fraction too long! The cure is to round-over all sharp corners as they do on car body panels. Only requires a small round-over.

Lesson 2: Make your rebated driver cut-outs around 0.5mm to 1mm oversize to allow for paint build up. When I tried to sand back the inside of the rebate this cut through the black and exposed the grey primer around the front edge! Not good.

Lesson 3: Don’t force dry the paint with heat. Allow it to harden off over night or for 24 hours before applying the final coats.

Lesson 4: Exposed ply edges require a lot of sealing. At least 2-3 coats of Sanding Sealer rubbed down between coats, especially around the driver rebate. Will also require body filler rubbed down to get any butt joints to be a true smooth and invisible finish. This is time consuming and labour intensive. We thought we had cracked this, especially around the driver rebates. However, when applying the black paint, this being a thinner more aggressive paint than the primer, it seeped under the top layer of ply in a couple places lifting the layers. So more rubbing back, filler and sanding back with fresh layer of paint!

Lesson 5: It would be far easier and cheaper to produce a Piano Black paint finish using MDF with round-over edges, rather than Birch Ply.

In the end I decided to veneer the speakers in my usual way first rubbing back all that nice paint finish so to give a key for the glue. I really hated having to do this but I just couldn’t live with the speakers with how the finish looked after I had tried to get the drivers to fit into the rebates.

I chose Zebrano as I am presently building another pair of speakers in this veneer and had just enough of the veneer left over to cover these smaller speakers. So here are a couple photos of my prototype pair ready for anyone who wants to come over and listen to them. When I have some spare time I shall knock up a pair these speakers in MDF, knowing now what to do prior to painting and then get the guy to just sray them with me doing all the labour intensive prep work. Hopefully second time around we’ll achieve that elusive piano black finish and too boot they will sound just as good as the veneered ply ones.

Click the image to open in full size.

Click the image to open in full size.

Last edited by Toppsy; 16th July 2012 at 11:36 AM. Reason: addition insert quote added
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Old 16th July 2012, 04:31 PM   #30
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Nice.
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