DIY 2-Way Speaker Review + Advice for Newbies!

[ChrisR1983]

Hello All

I'm posting this thread because I've just finished my DIY speakers and after a few teething problems I've just done a 2 and a half hour test including: Mozart - Requiem, Pink Martini - Sympathique, Beethoven - 9th Symphony, Martin Carthy & Dave Swarbrick - Life and Limb and finally Stevie Wonder - Songs in the key of life - all on CD of course, I'm only a youngster ;-)

So, how did I do it? I contact Neil Smith at Wilmslow Audio in the UK, got him to suggest some drivers, design a crossover and build me a stand-mount cabinet to suit. It cost about £200 (pre-veneered) and I was well happy.

Next I bought all the components. I got the best I could afford because I understood that this is a fairly crucial part of the speaker. I think I went overboard as I bought fancy Mundorf boutique caps, Duelund, stuff, etc. My advice to a new guy is DONT GO OVERBOARD. Remember, just because a professional has designed your crossover doesn't mean that YOU will like it. Try a few different designs & then buy fancy bits if you want to improve it.

One thing I noticed is - don't underestimate anything. The cost of things, the amount of time it will take or how much of something you may need. For example: internal speaker wire (hookup wire) - I bought 10 feet of some REALLY expensive wire, cut it all too short and wasted (ish) the lot. I ended up using some from Maplin that costed me about £2 for 20metres. Its fine and superb.

I would recommend getting the best drivers you can. I ended up with Scan-Speak D2904/7100 and 8531G00. I have to say the build quality is excellent. SHOP AROUND - I found mine at about £350 cheaper abroad than in the UK. They arrived in 2 days in perfect condition but BUDGET FOR IMPORT DUTY! I ordered nearly all my kit from the US and only got stung once.

An expense I didn't budget properly for was binding posts. I wanted something fancy and ended spending lots on WBT posts. In my opinion, unless you are an expert builder and have an AWESOME system (I don't... yet) then just get something that works. If you are not happy you can upgrade later.

So... I've rambled. What's my verdict... I've never heard anything like it. From a £19 DVD/CD player through a standard cable to a cheapo ebay amp to my £1800 speakers. I've nerver heard anything this good. Everything is so clear and the speakers 'throw' sound around the room. The bass is heavy but concise (I don't like boomy/strong bass) but the real fascinating bit is the high frequencies. Just amazing and crystal clear.

I'm now spending the next few weeks re-listening to my entire collection as I keep discovering things on tunes I've not heard before.

So, what do they look like? See attached. What do you think?

If anyone is interested in the design let me know

Cheers

Chris

[Jay_WJ]

Chris, I hate to say this when you seem to enjoy your new speakers. I looked at the crossover design you posted in your original build thread:

Crossover Nightmare/Sleepless Nights

It seems that this crossover basically relies on textbook formulas and maybe some hand/ear tuning after that. It has virtually no baffle step compensation built in there. If you really enjoy it, I have nothing to say further. But if you've looked for good hi-fi speakers whose tonal balance is neutral and precise, then this crossover is not for you. You chose some of the best, cutting-edge drive units on earth, and used them in a primitive way. Don't you feel their midrange too forward and bright? If not, I'm out

-jAy

[ChrisR1983]

Hi Jay

I do enjoy the speakers but I'm only about 80% happy with them. They are definately better than anything I've ever owned or better than anything I've every auditioned BUT: I do feel as though I'm not getting the very best out of them.

What do you suggest to improve them? Is there any way of improving them without having to just 'throw away' the crossover components I've invested in. I don't mind adding to the crossover but would like to get some return on investment for what I've bought.

Suggestions are more than welcome :-D

Chris

[Jay_WJ]

Chris,

I usually do my full modeling by incorporating baffle step loss/diffraction and box simulation results into drive units' published infinte baffle measurements. But since I don't have much time these days, this time I simply worked with crossover filters' transfer functions using drivers' impedance data. This approach works pretty well particularly for one, like me, who does crossover simulations frequently. First, take a look at your original crossover's transfer functions:



As you can see there's no baffle step compensation built into this crossover---no difference between 100 Hz and 1 kHz amplitude responses. This means that you hear less lower midrange and midbass than you need to. My predicted crossover frequency is around 3 kHz. The SS 7100 is a far better tweeter than many tweeters that could be crossed at 3 kHz.

Now take a look at Zaph's ZRT 2-way design's filter transfer functions:



Though his design uses a different tweeter (SS 6600), you get the idea. He compensated full 6 dB for the baffle step loss on the 8531G's response.

Finally, here is my suggested crossover and its filter transfer functions:



Mine has about 4-5 dB baffle step compensation, which will work in most listening rooms. The crossover point will be about 1.9 kHz. Note that the tweeter is wired in normal polarity (i.e., same polarity as the woofer is wired).

I provide a tweeter output adjustment option in case you need it. Replace the R2 resistor to increase or decrease the tweeter output. Default value is 6.8 ohm. A larger R2 value will increase the level and a smaller one will decrease it.

Here is my suggestion about crossover components. Rather than cannibalizing your current crossovers, I recommend purchasing inexpensive components to try the above crossover. Never use expensive components. 99.9 % of speaker system distortion is from drive units, not from crossover components. Simply use components of values and types specifed in my crossover schematic. Use iron core inductors for L1, and air core 18 or 20 gauge coils for L2. Use any inexpensive poly caps, and any resistors rated at 5 watts or greater. Is there any local or online store you can order these from?

If you like the new crossover, then you can cannibalize the previous ones and replace some parts with higher quality ones.

-jAy

[ChrisR1983]

Hi Jay

Thanks for taking the time to write that; I really appreciate it. I'll order the new components over the next few days and give it a try.

There are no local shops that sell this kind of thing so I tend to order from Parts Connexion or Hificollective.

I noticed a problem with the speakers as they are set up last night. They hate low volumes currently. I get so much crackle and pop and loss of volume momentarily. Not happy...

Many thanks

Chris

[Jay_WJ]

Chris,

If you haven't ordered the components yet, here's a little better modeling result I obtained. For C2, wire 5.6 uF and 0.68 uF caps in parallel.



If you have to order online, here's a great solution for you. Use the Erse Audio online store (www.erseaudio.com). They manufacture crossover components in house. Outstanding quality components at great prices. You don't need Mundorf or Duelund parts. You can use as good components at a fraction of costs. Erse also charges only actual shipping cost. So no problem ordering internationally. Email and ask them to send them, for example, via USPS Priority Mail. Shipping won't cost a lot. See attached below for BOM I made for you. Only $52 for xover components for a pair of speakers. Isn't it sweet?

-jAy

[ChrisR1983]

Jay that is awesome. Thanks so much!

[Jay_WJ]

By the way, you flush mounted the drivers in recessed cutouts, didn't you?

[ChrisR1983]

Yes Jay I did

[Jay_WJ]

Good. That's what I assumed. When you start building the crossovers, take a picture of your initial layout, and use Windows Paint to draw wiring including points to source and drivers. Post it here. Then I'll be able to let you know if anything's wrong or if there's a better inductor placement.

jAy