Amiga Build

[djg]

Mahogany PSA veneer done in an afternoon.

[PWR RYD]

Love your use of the party cups for size perspective! Tells me everything I need to know ;)

[djg]

Everyone knows how big a Solo cup is.

[joshshetter]

Very nice cabinets there. Design of your own?

I think I'll go with what I had linked if more research doesn't point me in a different direction.

[djg]

https://techtalk.parts-express.com/forum/speaker-project-gallery/1454432-next-build-cjd-s-abourious

[Operandi]

Crossovers are put together, annoyed by one of the inductors but as the leg didn't want to play how I wanted so it sticks out a bit. Boy I don't know what I'd do without these pcb's you can order on ebay.

Those corssovers boards look really nice. I didn't know this was something you could do. Would you mind sharing which seller you used, searching on eBay is kind of a nigthmare.

Speakers look great btw!

[joshshetter]

Just google "Amiga Crossover PCB" and it's the first result, ebay seller. They have PCB's for a few kits, not sure what one would do if they needed a custom PCB.

[Operandi]

Oh, ok I thought they were doing custom PCBs specific to audio PCBs. Not sure as I haven't tried them but I think Madisound does but they do the entire crossover with components.

[djg]

It's Matt Grant associated with DIYSG. I used a pair in the S2000 MTMs I built. They are very nicely made.

[joshshetter]

I'm unsure of whether to finish these guys. I'm finding that I don't care for the tweeter too much. The initial honeymoon phase is over and there's some hump around the 5300hz region that doesn't gel with me at all. I have Dirac running on them and it really cleans them up a lot. I frankly find them quite shouty without the EQ. I don't know if I want to invest the money and time into a finish for a speaker that has such an issue.

So I've got xsim out and playing with the design and some other tweeters, and some xover mods. Might try something else, noticed that a lot of the soft dome peerless tweeters have a little bump at 5300hz on the tymphany sites measurements, wonder if that's a test rig thing or something inherent to many of their soft domes.

[joshshetter]

You can see the hump here in my dirac measurements. Makes the speaker quite annoying to listen to.

[davidB]

If the EQ works, try a shallow notch in that area(as you weaken it with parallel resistance you will widen it, so you can pull the whole area back into line with the general power response slope you have going).

Don't give up on a good tweeter at the first problem.

[Basshead]

Sorry to hijack your thread… I was drawn to these speakers from their name and having used the computer with the same name since the late 80’s. I’m considering these speakers as a replacement for the front mains (L and R) for Paul Carmody’s Swope HT. Apart from the different drivers, would anyone know if this would be an issue?

Also, do the Amiga flat-pack (knock-down) kits come as a pair, or single (ie. would I need to buy 2 kits to build 2 speakers, or just one kit)? From the photos on the item description it implies there are parts for just one speaker, meaning I’d need 2 kits

[Wolf]

1 cab/purchase, they do not come in pairs.
Wolf

[Basshead]

Thanks Wolf.

After further reading of the forum and PM’s with Geoff Millar, it’s likely the freight costs (to Australia) combined with the exchange rate will bump up the price of the knock-down kits (even with just the baffle) substantially.

I’ve been unable to locate any threads with specific details or plans showing the port dimensions for the Amiga (nor can I find them on Paul’s pages) - does anyone have the details?

Also, as I’ll likely be sourcing the drivers locally, is the RS180-S (as shown in the crossover diagram) the same as the RS-180-8? (Perhaps that just a typo or the model number has changed slightly in the past decade?). I’m assuming I need the 8ohm version?

The RS180-8 is presently AU$119ea locally (compared to <US$50 on PE) and the tweeters are approx AU$60ea locally (compared to US$20ea on PE). As a rough guide, US$20 (with straight exchange rate only) is approx AU$30 so we’re paying double the US prices for the same gear here in Australia. And that’s before freight and possible GST.

[djg]

Have you investigated sourcing your components from SB Acoustics in Indonesia? Top quality, maybe different supply chain. Going from China to US to AU is just crazy.

[Geoff Millar]

:From Paul's website:

https://sites.google.com/site/undefinition/floorstanding-speakers/amiga

"The cabinet is about 30 Liters internally, and is tuned to 39 Hz. This gives an F3 of 34 Hz (ooh, yeah!). The vent is 2" diameter and is 3.5" inches long."

When I bought our RS180P-8s (same price as the al version) they were A$64 each, shows you what's happened to our $ since then. At the time, something like the Peerless 830883 was about $90, now it's $109 so they haven't gone up as much in comparison, nor have SB drivers.

Money aside however, the RS180P is a great sounding, great looking woofer and the $$ are forgotten once we play some music.

Geoff

[Chris Roemer]

In the beginning ...

the 1st batch of RS (Al-coned) drivers were ALL shielded (remember CRTs?). Later (after the demise of CRTs) the shielding was dropped (co$t $avings - I presume?) without really changing the drivers names. (There WAS/is? a "shielded" woofer still made to drop into the most popular designs - could be the 180? - 180S now.)

Many designers tried dropping the NEW RS (unshielded) drivers into designs that started out w/the "original" (shielded) drivers, and almost all of them decided that the new versions could drop in w/out any crossover changes (and MOST box sizes/tunings were adequately "close" as well).
8ohm vs 4ohm designs require major XO changes.

[Basshead]

djg SB Acoustics in Indonesia - I checked their website and it appears they have different driver brands; are they copies or replaceable with Dayton RS180's?

Geoff Millar "The vent is 2" diameter and is 3.5" inches long" somehow I managed to completely overlook that sentence!


Chris Roemer So it's safe to assume the "-s" suffix denotes the "shielded" version of the driver and it will have little impact overall. I already know the difference in voice coil resistance affects the selection of XO components.

[djg]

SB Acoustics is a manufacturer of quality speakers. There are many DIY designs using them. You could not build an Amiga speaker with SBA components.

[Geoff Millar]

SB makes very nice drivers, have used their budget level SB16PFC in a two way, it sounds good although not quite on a level with the RS180P; but less than half its price. However, that's the cheapie of the range: SB has drivers at many price points and there are many builds using their woofers and/or tweeters.

A key thing when you can't audition a speaker is that there are enough builds so you can get an idea of the sound: a lot of people have built the Amigas and are happy with the sound. Many reviews, too. Lots of projects with SB drivers also, but perhaps not as many builds and reviews?

[djg]

I mentioned SBA because I thought maybe cheaper shipping to Australia. I'd rather spend on quality than shipping.

[Basshead]

I did a mock order on PE with just the 4x drivers only (for 2x Amiga’s) and the freight came to US$105. With adding one pair of XO inductors it added just a couple of dollars. Potentially it could go up to around US$150 for freight of all parts (excluding mdf) to Australia.

Out of curiosity, I tried a new mock order of 2x amiga knock down kits (which are now also out of stock - but weren’t a couple of days ago) and freight came to a whopping US$386!!! (That still needs to be converted to AU$ so around $500!!!). From trying some local suppliers, it seems no one company has current stock of all the parts, so I’d need to buy from multiple suppliers to make the pair.

[djg]

There are other speakers besides Amigas.

[Geoff Millar]

From my googling, I think you can get the parts from two sources,so what's involved is about $10-$15 in extra post. The drivers are listed as in stock at one supplier.

I just noticed that the DX25 at that supplier is listed as a Scan Speak (Denmark made) replacement for the Vifa DX25TG05-04. The original tweeter for the Amigas was the DX25TG09-04, so it's worth checking if that's a direct replacement: I suggest you post a separate question on PETT for that issue, I'm sure Paul will see it.

I found that when building our speakers, the main problem was not the driver and crossover parts, but getting the MDF cut. No-one was interested in doing the driver rebates, which is why I had to do them myself. Only two firms in Melbourne would cut the MDF for me.

Geoff

[joshshetter]

Added two subs to my Amiga setup, sounds awesome. I find adding them really helps clean up the sort of bright sound I was feeling the speakers had. I have no filtering on the Amigas yet, subs crossed fairly high to avoid that sort of 100hz emptiness. I can probably figure out a way to route the motu m4 I'm using to filter some of the lows of the Amigas although things sound really nice and tight as is. I tried plugging the ports of the Amigas but they lost some "open-ness"? Hard to describe.

[joshshetter]

Did some outdoor measurements. Doesn't really look very good. Some pretty obvious issues that I find audibly annoying and make me dislike the speaker overall. Measurements below 200-300 can be ignored.

That dip in the mid range sucks, feels like there's a disconnect between the musical content that is there. I can try to bring it back in but can't settle on anything that sounds correct.

Oh well guess I'll offload these to a friend and try something else.

[Chris Roemer]

josh, not sure if you tried Paul's suggestion to drop the value of R2 or not, but your measurements match the orig. designer's nearly to a tee!
Also not sure what XO changes you tried to "flatten"? the FR above 1k, but I could make a suggestion or 2 if you'd like.
A "notch" over the 4-10k range MIGHT help. And if you don't feel that area is too bright, the notch along w/unpadding the tweeter MIGHT bring up the 2-4k octave (possibly even tweaking the HP "knee" a bit).

As you know, MOST peeps are quite happy w/the sound of these ...

[joshshetter]

I have +2db at 2300hz and -1db with wide bandwidth at 5400hz. I think this speaker has a directivity error around the xover as a lot of two ways do and it makes it difficult to EQ the issues.

I'm sure most people are happy, but I'm a little more discerning than most. I very much prefer neutrality and have some speakers that exhibit that, so when I get a speaker like this with problems, the music just doesn't sound right and all I can hear are the issues. Oh well.

I think the classix II sound better in some ways, but they definitely measure better, very smooth response. I find the amigas to be comparatively and audibly jagged in response.

[djg]

You should probably start designing your own.

And some people say it's not safe to burn MDF.