New project. Beyma 8p300 plus Scan speak R2604

[Drummer 35]

Hi all,

I´d like to build a pair of speaker using that driver:

Beyma Speakers - Beyma 8P300Fe/N speaker - Beyma 8P300Fe/N 600 watt 8" speaker for all bass applications. Beyma 8P300Fe/N bass speaker and other Beyma 8" speakers here. Beyma 8P300Fe

and that tweeter:

https://www.madisoundspeakerstore.c...covery-r2604/8330-tweeter-dual-ring-radiator/

I decided to use that driver since it works well up to 5000hz and I can get them for a fair price. I think that it can work well with those tweeters. Anyway, it will be my first diy speaker so I´d like to know if you think it will work or not.

The tweeter impedance is 4 ohm while the driver is 8, so Ill need advice too with the crossover.

Help much apreciated

David

 

[silverprout]

Hi all,

I´d like to build a pair of speaker using that driver:

Beyma Speakers - Beyma 8P300Fe/N speaker - Beyma 8P300Fe/N 600 watt 8" speaker for all bass applications. Beyma 8P300Fe/N bass speaker and other Beyma 8" speakers here. Beyma 8P300Fe

and that tweeter:

https://www.madisoundspeakerstore.c...covery-r2604/8330-tweeter-dual-ring-radiator/

I decided to use that driver since it works well up to 5000hz and I can get them for a fair price. I think that it can work well with those tweeters. Anyway, it will be my first diy speaker so I´d like to know if you think it will work or not.

The tweeter impedance is 4 ohm while the driver is 8, so Ill need advice too with the crossover.

Help much apreciated

David

The next step is to fix your crossover frequency

 

[Trollet]

I have a bunch of Beyma's; 2x8G40's and CP21. They work fine but I'm crossing at ~4200 hz and the 8's starts beaming at ~3khz.
I would look for a tweeter that you can cross around 2500 hz.
You have to consider that those 8's can take a lot of power, and the Scanspeaks propably will go up in smoke...

Figge

 

[eriksquires]

Nice driver choices, but you can get the tweeter for half if it says "Vifa" on it.

Erik

 

[eriksquires]

The dual magnet version of that tweeter goes down to 2k by the way. The Vifa XT25BG60

https://www.parts-express.com/peerl...shielded-dual-ring-radiator-tweeter--264-1012

I use it in the LM-1, so you can check out the thread on that and the XSim files to help you learn about crossover design.

Just curious, how big a cabinet are you going to need??

Best,

Erik

 

[Drummer 35]

Thanks for your answers. Very helpful.

I have a bunch of Beyma's; 2x8G40's and CP21. They work fine but I'm crossing at ~4200 hz and the 8's starts beaming at ~3khz.
I would look for a tweeter that you can cross around 2500 hz.
You have to consider that those 8's can take a lot of power, and the Scanspeaks propably will go up in smoke...

Figge

looking at the technical specs, I see the freq range for the 8g40 is 65 to 6000hz while the 8p300 is 50 to 8000hz. Do you think a crossover around 4000-5000 would work?

I´d like to use that tweeter since I read very good reviews about it, and it fits my budget.

As you say, the beymas can take a lot of power, and has a sensitivity of 95db/8ohm, while the scanspeak is 90db/4ohm. Id like to design a crossover to compensate that difference in sensivity/impedance.

I can make my own boards but the problem is that I dont know how to calculate it. 1st or 2nd order crossover?

Thanks a lot for your help.

 

[eriksquires]

Thanks for your answers. Very helpful.



looking at the technical specs, I see the freq range for the 8g40 is 65 to 6000hz while the 8p300 is 50 to 8000hz. Do you think a crossover around 4000-5000 would work?

I´d like to use that tweeter since I read very good reviews about it, and it fits my budget.

As you say, the beymas can take a lot of power, and has a sensitivity of 95db/8ohm, while the scanspeak is 90db/4ohm. Id like to design a crossover to compensate that difference in sensivity/impedance.

I can make my own boards but the problem is that I dont know how to calculate it. 1st or 2nd order crossover?

Thanks a lot for your help.

The least of your issues is the crossover design. Your first order of business is building your cabinet, placing your drivers and measuring it. Then crossover design can begin.

Please take a look at the ongoing A26 and LM-1 threads using XSim. It will give you a good starting point/idea of how crossovers work.

Best,


Erik

 

[eriksquires]

BTW, my point was, as far as I know, Scanspeak sells the exact same tweeter under the Peerless/Vifa brand for half price.

The dual magnet versions, with better low end extension, are as good if not better than the single magnet version.

Best,

Erik

 

[Face]

looking at the technical specs, I see the freq range for the 8g40 is 65 to 6000hz while the 8p300 is 50 to 8000hz. Do you think a crossover around 4000-5000 would work?

I´d like to use that tweeter since I read very good reviews about it, and it fits my budget.

As you say, the beymas can take a lot of power, and has a sensitivity of 95db/8ohm, while the scanspeak is 90db/4ohm. Id like to design a crossover to compensate that difference in sensivity/impedance.

That technical spec is useless. Generally you should cross an 8 around 1200-1600hz. 2k would be pushing it, but still doable.

Another issue I see is the tweeter isn't efficient enough. It's easy to pad down a tweeter, but padding down a woofer isn't recommend.

 

[Drummer 35]

Erik,

Thanks for the info on the tweeters. I´ll order the XT25BG then, great price!

People talk very good about that tweeter... for only 40 bucks!

About the cabinets. It will be done in solid wood (beech, walnut or the like). A friend of mine is a furniture maker and has a CNC machine, so I expect the finish to be A grade.

About dimensions, Im limited in front width to 35cm, rear width 20 maximun, depth 40cm max. and 55cm height. I think it has enough volume for that driver. Any consideration about shape/aspect ratio? Any help or advice will be welcome .

Also, I thought to build it first without vent, and if I need more "bass" Ill open a front vent.

The prototype will be done in cheap wood, so I can do all that tests.

Thanks!

 

[Drummer 35]

Face,

If I set the crossover to 2k, the problem is to find a tweeter with that huge range, and I dont want to go with a 3 way design. Any high efficiency - high range tweeter you can recommend? I thought about the xt25/R2604 but maybe is not the best option.

 

[eriksquires]

It is an outstanding tweeter. One version or another has been used by Krell, Sonus Faber and YG as well as the LM-1, the single most important free speaker kit ever.

Erik

 

[Dissi]

Hi Drummer,

Those ring radiators are not really suitable for the combination with a high efficient 8" woofer. Rather use a horn loaded tweeter in order to have less issues with sensitivity, power handling, crossover frequency and impedance:

https://www.madisoundspeakerstore.com/soft-dome-tweeters-scanspeak/scan-speak-discovery-h2606/9200-horn-loaded-1-textile-dome-tweeter/

 

[eriksquires]

I forgot to check the sensitivity. The woofer is listed as 95, tweeter is 92. I wouldn't say it's impossible, but it will be close. You'll probably end up adding some amount of Baffle Step Compensation anyway, and loose some of the woofer efficiency. With a little luck, you'll come in at or just under the tweeter level.

 

[eriksquires]

Er, actually the woofer is 93 dB! Perfect.

Spec wise, it should work. You'll probably loose at least 2 dB for BSC, so that will put your woofer just below your tweeter, letting you pad the tweeteer down within easy reach.

Now, whether that woofer will come alive with very little power is what will matter the most.

Best,

Erik

 

[Charles Darwin]

I would consider a waveguide for the tweeter.
Increses the low end output, gives some extra dB per watt and the dispersion at crossover would be much better matched to the Beyma.

If I remember correctly a member posted a file to 3d print and adapter to fit the XT25 to the Monacor WG300 which would make life a lot easier.

 

[Trollet]

I've used Beyma CD10Fe and a short horn/wave guide with good result with 8G40.
As already been said, sensitivity match will be ok when baffle step correction is applied.
Crossing at higher frequency will give you beaming effects so keep it as low as possible.

Those drivers also needs very stable cabinets, not to be compared to any regular hifi woofer.
They can sound superb for shure.

Figge

 

[454Casull]

BTW, my point was, as far as I know, Scanspeak sells the exact same tweeter under the Peerless/Vifa brand for half price.

The dual magnet versions, with better low end extension, are as good if not better than the single magnet version.

Best,

Erik

I'm pretty sure all the Discovery units are made in Denmark. Many, if not all, of Vifa's units are made in Asia.

 

[Drummer 35]

Thanks guys.

Erik,

as you say, I may have problems with the r2604 when I crank up the volume. The 8p300 can handle a lot more power and is more efficient. Using a different driver is not an option. I already ordered the woofers.

Charles,

What kind of waveguide? I love those "radiators" in the vintage JBLs but not sure if it´s what do you refer.

If been looking for a powerful-detailed tweeter and found the CP21. (similar to those on the JBL L300s and 4333) it has a 140º x40º dispersion. Its 105db SPL so it can keep with the driver. what do you think?

Beyma CP21F - Beyma CP21F 1" high frequency slot tweeter. Beyma speaker components available at US Speaker.

The problem, as you say, is to crossover the two.

Looking at the graphs on both, I think the CP21 won´t like to go that low to "mix" with the 8" so...

do you think I could add a second tweeter? I mean, build something like a scaled down L300 using the 8p300+cp21+ "mid" tweeter.

Thanks again for your help!

 

[Charles Darwin]

I mean this waveguide:
https://www.monacor.com/de-de/monacor/produkte/components/lautsprechertechnik/selbstbau/wg-300/

When mated to the lesser of the Vifa/Peerless/Tymphani ring gadiators it measures like this:
Test Vifa XT-300/K4 (XT25TG-30/04) am Waveguide WG-300 / PCT-300Horn – Heißmann Acoustics